993 Windscreen Creak Down Under

 

 

 

A very common 993 windscreen issue as illustrated by a frustrated owner via email:

“I was hoping you might be able to help me out, I am in Australia at the moment and just had a new original front window installed in my Porsche 993 (the windscreen was an insurance claim and the car was being repainted at the same time so no issue with the surface as it was all freshly painted and all new seals etc and original Porsche parts).”

A freshly painted 993 and a new windscreen. Sounds like a good start, however…

“The window creaks (both at highway speed and at lower speeds around town). I supplied the Porsche tape with the car and the guys installing tell me they had done plenty of 993s without problem. Since the window was installed and creaks started they tell me they did not use the tape and mine is the first window they have ever had problems with. They are telling me to live with it at this stage which naturally I am not overly pleased with.”

The installer’s  defence of the ‘first window they have ever had problems with’ is quite ambiguous; it could mean:

  1. they have been getting away with it thus far;
  2. none of their previous customers kept the car for any period after the windscreen was replaced, therefore, a new owner somewhere else inherited the problem with the purchase;
  3. the previous 993 windscreen installs were better than this one. The fact that they say this car is the first one they’ve had problems with is pretty much an admission that they have encountered (or are about to encounter) an undeniable problem with the job;
  4. or that the car owner is being overly fussy about something that they don’t identify as a problem.

“They tell me if they reinstall it there is a high likelihood that they will damage the antenna ribbon and then another new windscreen will be required.”

This. Is. A. Fallacy. An utterly mistaken belief, based on an unsound claim. The same can be said about most ‘the glass might break on removal’ caveats. The point in question here is that it is a customer complaint. If the ribbon (cable) is damaged, it is entirely at the installer’s risk: you damage it – you replace it; it’s your problem to fix. Furthermore, this ‘the glass might break on removal’ is a cop-out. If the glass breaks it’s because you broke it, is it not? A good installer will identify a problem before it arises. Yes, there is a realistic chance that it could break but when with the benefit of experience, skill along with the virtue of patience, the failure rate is less than 1%. If the ribbon cable (or antenna which, on the 993, is embedded in the glass and threaded through into the cabin behind the clock) was a casualty the last time you attempted to remove the windscreen, hmm, here’s a thought: try doing it a different way? Experience is knowing the pitfalls of your trade and more importantly, how to avoid them.

“I read your blog again but still had a few questions…”

Time for some concise answers…

“If the window is creaking it is moving and the issue needs to be fixed ?”

Correct. It hasn’t been fitted correctly and needs to be remedied.

“Should the tape be used ?”

No. Nein. Nie.

The VIN number is slightly obscured by the window (to be fair you could not see it at all with the last window so it is better but I read somewhere this is an indication that the install alignment is not good enough) ?

Yes. Sometimes the plate can be misalligned, and the silkprint can also be out on the glass. The combination of the two can obscure some of the VIN (horizontally). There is some scope to adjust by a few milimeters (more vertically) but in any case, all of this can be seen before bonding the windscreen in. Dry fit it. Test fit it. Simples.

ADAS Recalibration After Windscreen Replacement

 

 

 

Have you had your windscreen replaced recently? Is your car equipped with an Advanced Driver-Assistance System? Were you advised (or even warned) about the need to recalibrate that device? Whether your ‘smart’ windscreen has been replaced or not, there is a realistic chance that it might need to be in the future, and this is where you could be faced with more questions… or perhaps not. The subject of recalibrating ADAS devices is a Pandora’s Box full of unsubstantiated claims.

For those new to the technology, some background: ADAS systems are designed and developed to automate and enhance vehicle systems for safer and better driving. These features are designed to help with monitoring, warning, braking, and steering tasks. ADAS relies on inputs from multiple data sources, including automotive imaging, LiDAR, RADAR, image processing and computer vision. These devices are mounted in various places in and around the vehicle; some are mounted behind the windscreen.

ADAS

Advanced Driver-Assistance Systems

Advanced driver-assistance systems are one of the fastest-growing segments in automotive electronics. In terms of car design and evolution, motorists are in safe hands. Ultimately, and until we have autonomous vehicles, the motorist’s hands should however still be on the steering wheel.

Does your camera (or device) need recalibrating after the windscreen has been replaced?

There are a variety of factors to consider, but to cover all bases the blanket response would be to say yes it does. However, before the recalibration apparatus was made available to repair shops, windscreens on cars with ADAS were still being replaced. If the answer is to be yes, why haven’t those vehicles been recalled? The counter argument to that could also be that none of those vehicles needed adjustment, or even, none of them went into default mode after having the windscreen replaced and, worse still, crashed as a result of a misaligned device. There are no reported cases of crashes, injuries or fatalities which were attributed to an uncalibrated camera. Meanwhile, the same cameras are still being recalibrated today.

A motorist emailed me to ask if his device needed calibrating post windscreen replacement. His vehicle featured ‘road sign assist’ which he said he didn’t use anyway. The company who were replacing his windscreen stated that he must drive the car to another one of their sites (30 miles away) to have the camera recalibrated. There was an additional cost implication to this procedure (over £150) as well as his time and fuel to get him there and back. If it was – according the repairer – paramount for his safety why were they sending him on his way, in the compromised car, to another destination 30 miles away? He went ahead and had his windscreen replaced but decided against the recalibration procedure on the basis that he didn’t agree with paying what they were asking for, and then having to embark on a 60-mile round trip in order to get it. Interestingly, he later had his vehicle checked by a manufacturer main agent and there were no flags or faults in the vehicles computer system. Everything worked as it should. The Road Sign Assist device checked out okay.

Traffic Sign Assist

When replacing the windscreen on a vehicle, if the windscreen is a genuine OE product and you are fitting it using the correct bump-stops/trims/damming/mounting components, and within OEM tolerances, as long as you do not disconnect the ADAS device and put the vehicle through an ignition cycle, there is nothing to detect the new part.

Put simply, if you are using manufacturer branded products, fitting them to millimeter precision, and do not put the vehicle through an ignition cycle [with a device disconnected] the car will not know the windscreen has been replaced. It is therefore unlikely that you will encounter any issues. Furthermore, many (if not most) devices are auto-calibrating. They have to be, to allow for constant variables during use. The issues occur mostly (in terms of windscreen replacement) when non-genuine parts are used (referred to as aftermarket parts). Comparing an OE windscreen to an aftermarket copy of it, the differences often become immediately apparent such as misaligned brackets (to which the ADAS device is mounted) or that the material used is inferior. When you mount a camera to its bracket or plate which itself is not positioned correctly, the accuracy of that device is immediately compromised. This therefore, is a scenario where recalibration would be needed. Original parts do not offer any such issues.

The (American-based) Insurance Institute for Highway Safety conducted testing of windscreen-mounted advanced driver assistance systems in 2017 and found that a misaligned camera [on a test vehicle] led to issues with the vehicle’s autobraking and lane-departure warning functions. Honda Collision Marketing Assistant Manager Scott Kaboos summarised after the research that Honda required OEM windscreens be used and that they had seen “many issues” where aftermarket glass led to a situation where the calibration would not “take properly.” After the [repair] shop replaced the windscreen with an OEM edition, “everything worked fine again.” Kaboos stated.

IIHS senior test coordinator Sean O’Malley stated that this demonstrated the need for calibration rather than a ban on aftermarket parts concluding that, “The bottom line is that it could still be calibrated to work as intended.” While a factory-misaligned bracket was found on an aftermarket windscreen, the IIHS found no real issues with aftermarket glass itself, according to O’Malley. Chemical composition, laser refraction and refractive index testing found largely that ‘glass is glass’.

In the UK there have been no reports or stories in the press about firms – nor individuals – being taken to task over negligence. Why? Is it because there have yet not (and thankfully)  been any incidents? Could it also be that there actually isn’t any requirement for an installer to carry out a recalibration? In the same way that any Fred-in-a-shed-with-a-bag-of-tools can replace a windscreen among all the cries of how important structural rigidity is, and how airbags rely on the windscreen to be adequately bonded in order to be effective (provided the occupants are wearing seatbelts in the first instance) anyone can also replace the windscreen on a car equipped with ADAS technology. Is it compulsory to recalibrate those devices? No. Is it necessary to recalibrate them? Maybe.

Whether recalibration is compulsory (after windscreen replacement) or not, are they being checked correctly? Where are the before and after test results? Who is regulating that part of the industry? Who is policing it? How do we know that the procedure was actually carried out? Where is the second printout showing how much adjustment is or was needed? Proof? Is it merely a box-ticking exercise to distance from blame, or something to staple to the invoice to validate the extra charge?

This is a subject that will run for a while, and during that time the ones making the loudest claims in favour of recalibration are also looking for a return on their investment into what is being sold throughout the motor industry as a revenue stream.

Have you had an experience to do with ADAS and windscreen replacement, good, bad or indifferent? Please get in touch.

 

 

Unskilled Windscreen Fitters

 

 

Many windscreen fitters say they’re experienced, but what kind of experience that really is will show in the end product or in the way they do their job. A windscreen fitter can be judged on how he or she fits a windscreen.

Bonded windscreens: applying the adhesive. 

How Wide?

Compressed, the Polyurethane adhesive (PUR) bead wall usually (should) end up about 10-15mm wide. This can be achieved using a trim and (or) appropriate spacers/paking blocks/bump stops dependent on the application. A ‘V’ shaped cut in the nozzle (of the extruder) will stand the bead up to about 12mm but this is variable depending on the regulation of extrustion, angle of extruder (it should be perpendicular, to the substrate BTW) and generally the combination of the aforementioned togethered with the speed in which you get the whole thing around the glass or frame to which it will be bonded.

BMW E36 Compact

Whoever fitted this BMW E36 Compact windscreen did not get any of that memo, obviously. There’s just no excuse for it.

Why should anyone be concerned about this? There are some technical details which I’ll spare (unless anyone really wants to know) but at some point in the car’s timeline the windscreeb will need replacing, and to do that someone has to come along and cut this windscreen out. And when, in your mind, you think the job will only take you *so* long, and it ends up taking twice as long because Mr Numpy Balloonhead stood the bead up as high as a prison wall, then squashed it down by pushing the windscreen FLAT against the pinchweld leaving barely a millimeter of PUR sandwiched between the two surfaces, your opinion of some [alleged] windscreen fitters is reinforced.

A few sweary words were shouted during the removal of this windscreen.

All this fitter had to do was give a flying proverbial. it would have been easier to whack a couple of rubber blocks against the bead to allow the windscreen to bed evenly.

 

An Appetite for Claiming is Costing Us All

 

 

In the event that you should need a new windscreen, provided your policy indemnifies you for cracked or damaged glass, your insurer may direct you towards their ‘approved’ repairer. Opting for a repairer of your own choosing may not be so easy, and there may be a capped payout on any claim you might make. When a windscreen is repaired or replaced, insurers rely on their approved repairers to make an honest assessment on their behalf but ultimately, the onus is also on the policyholder to make the right call.

What happens when the policyholder makes a dishonest claim, or, for the benefit of doubt is unaware that they are about to make a spurious claim? The answer to this is quite simple; they usually end up with a new windscreen. Perhaps the insurers – or brokers – should place greater emphasis on what qualifies as criteria for a claim, or more what constitutes as a fraudulent one? This is where the approved repairer comes in. They are called approved because one of their responsibilities is to make an honest and frank assessment [of the damage] on behalf of their partner, the underwriter, before any loss can be indemnified. Experience tells us that this is a gray area; therefore, and by process of elimination, the onus lies on the insurer – or underwriter – to make clear what they will indemnify, and more importantly what they will not. They’re in the business of compensating loss however by definition they also need to safeguard their financial interests against dishonest and fraudulent claims. Considering how easy it can be to claim for a windscreen which, for example, may have been damaged before the car was insured it would appear that underwriters accept that they will be settling windscreen claims regardless of the facts (or lack of). They’re not helping themselves and in doing so, are leaving the door wide open for insured parties to claim for damage which may not be covered; they are also implicitly trusting the word of the repairers doing the work because  [rhetorical question alert] how many windscreen companies refer customers back to their insurer if they feel the damage does not meet the repair or replace criteria? The reality is, nobody seems to care enough; meanwhile the cost of motor insurance continues to rise and spurious windscreen claims are part of a much wider and cultural problem.

It has been said (usually by those trying to justify it) that fraud is a harsh word to describe deceit or breach of confidence, perpetrated for profit or to gain some unfair or dishonest advantage when it comes to making a windscreen claim. The act can be described in a variety of ways: cheating, deceit, scam, con etc. It’s being dishonest; exhibiting lack of honesty; fraudulent. Many do so innocently but whilst there is a strong argument for and against ignorance, if the insurer or its representative is not checking the validity of your claim to a claim, those who are well aware of their actions can have their windscreen replaced 23 hours before their conscience kicks in. 

 

“I have just bought a Porsche and the windscreen is scratched. Can it be polished?”

 

Case example. The type of question above is asked a lot on various motoring forums. In brief, scratched glass can be polished but not as a rule of thumb; laminated glass especially if it is the windscreen i.e., forward facing glass, can often lead to other consequential issues such as distortion [in the glass] and cracking (as a result of the heat generated from machine polishing). The real issue here is that none of the ‘approved’ windscreen repairers offer glass polishing as a service. Furthermore, in terms of what you’re covered for, scratched glass is (usually) not indemnifiable or construed as damage or loss. With that in mind, for the scratches which can be polished successfully, insurers can balk at the idea of paying for polishing services which in itself appears to be a bizarre stance given the cost of some replacement windscreens. Conversely, if polishing a scratched windscreen will cost around £100.00, a lesser excess of £75.00 will get the insured party a new windscreen. In this context it’s a no-brainer. Also, fast forward to when the approved repairer rocks up to replace the glass, there is no emphasis on him or her to question why the glass is being replaced: scratched glass may not be an MOT failure, and in any case, if the insurer does not payout for scratched or scuffed glass it won’t be an insured loss. The focus however, is for the windscreen fitter to actually fit the glass as quickly as possible and move on to the next job because that’s what his manager wants: a new windscreen is what the customer also wants. The same culture of replacing exists with chipped windscreens, or glass which is delaminating or pitted.

 

“Accidentally drive into a flying hammer and let your insurance company do the rest… wink, wink”

 

Insurance companies are not doing enough to ensure that claims are genuine and that only genuine claims can be made. Equally, their nominated or approved repairers are too busy to query the validity of questionable claims. They have their own targets to aim at and service delivery agreements to fulfill. The flip-side of this coin is that the policyholders can often place their own demands and ransoms on the situation. “I’m sorry, sir but that chip is perfectly repairable.” “I don’t want a repair; I want a new windscreen!”

As much as consumers are being spoiled by service providers, who in turn are pandering to their, as well as the insurance company’s demands, the insurer rubber stamps invoices and files them as ‘settled’, job done. Easy. And on the basis that any free lunches will be paid for somewhere eventually, the average motorist can look forward to higher insurance premiums further down the road. Yes, there are other significant factors which contribute towards the cost of motor insurance but calculating risk – actuary – is extremely complex and much of the profiling is extracted from claim statistics and calculations formulated from mathematical probabilities. Added to this are injury and fraudulent claims. This article focuses on one of those elements: flaws in the windscreen claims system and the claims culture cultivated by consumers. 

 

Related post: Leaking Windscreens are NOT covered.

 

 

 

Helping You Understand the Ballocks and the Bullshit

 

Have you had your windscreen repaired recently? How did the attempt turn out? Was the repair good, bad or indifferent? Were you confused about what you were told (by the repairer) at any stage? If you were, the chances are you had the wool pulled over your eyes.

3

Excuses for Poor Workmanship.

 

 

“Please understand: The largest misconception regarding chips is that they will disappear once repair has been done on the chip. The sole purpose of a stone chip repair is to maintain the structural integrity of the windscreen. Any aesthetic improvements are considered a bonus.”

 

Take a moment to comprehend what the message conveys.  The first part of the statement is true; repaired chips (or cracks) don’t disappear. There will always be some evidence of the repair. It’s not magic. How much you can see after the attempt to repair usually indicates how good – or not – the repairer is. The rest of the statement makes no sense, “The sole purpose of a chip repair is to maintain the structural integrity of the windscreen”. This sounds very technical and anyone with a damaged windscreen would be sitting up and taking notice. However all of this is undone with the closing line: “any aesthetic improvements are considered a bonus”.  In effect, you might as well say you rubbed your hand over the damage, so it should be fine. The very fact that there is a technical process in attempting to repair a damaged windscreen means, by definition, that there must be a discernible difference if that attempt is successful?

Some technical background to this is in order.

A windscreen repair technician should know how to repair a break , or what the likeliest outcome from his or her assessment of the damage. Understanding the science behind windscreen repair can help the repairer not only perform successful repairs but also educate their customers about the process instead of conning them of their money. Claiming that the break has been ‘filled’ or ‘sealed’ despite it looking the same after the process than it did before the technician started is probably the most common excuse. Most of these guys probably wouldn’t know what a good repair looks like never mind know how to go about achieving one

 

Preparing the Damage

To attempt a successful windscreen repair, you must rid the damage of air, contamination and moisture. Any loose debris must also be removed. This process alone debunks the ‘any aesthetic improvements are considered a bonus’ line, and shows how easily you can be fooled by someone purporting to know what they’re doing under their professional guise and pitch. The next step is to fill all areas of the break with resin. This may seem pretty straightforward, but it is not as simple as it sounds; to induce repair resin sufficiently requires different skills depending on the type of break. Time to ask Mr Aesthetic-Improvement-is-a-Bonus how to tell the difference between damage with resin in it and one without, perhaps?

Understanding the Break

There is usually an impact point although damage can still occur below the glass surface. This can be as small as a pinhead or a much larger impact crater which can extend from a couple of millimeters to way over the repairable limit (determined by the injector diameter). Behind the impact will be a circular shape (sometimes appearing to be dark or black) or a conal appearance in the glass. This is a basic cone – or part cone – damage and arguably the easiest to repair as most of the ‘bullseye’ or ‘half-moon’ appearance (if filled adequately) will be reduced to a slight watermark appearance once the process is complete. Small cracks or ‘legs’ radiating from the damage center form the more complex breaks and are generally more difficult to fill (and come with a slightly higher risk factor attached; the more legs, the greater the chance of one of them extending or cracking off). An experienced and properly trained repair technician will know how to manipulate the different types of damage in order to get the resin to flow (there are variables on this too). Irrespective of the type of damage you must remove any trapped air to allow the resin to flow. Ideally, you should remove any air from the break before any resin comes in contact with the damage. There are times that air must be drawn out during the repair; this has to be pulled through the resin by way of vacuum and pressure cycles (the force acting upon the air must be stronger than the surface tension of the resin in its way).

The Resin

The most important quality of a repair resin is its performance. First, the resin must be able to enter and reach all areas of the damage; product viscosity and by this, velocity (under applied pressure or vacuum). The cured resin should also have enough tensile strength to withstand any flexing, expansion or contraction that the windscreen may be subjected to.

Repair resin also needs to correspond to the same tensile strengths or have enough strength to withstand the expansion and contraction of the glass around it. Two characteristics make up the total tensile strength of the resin: adhesive strength and cohesive strength. Adhesive strength is the ability of the resin to adhere to the glass, and cohesive strength is the resin’s ability to hold itself together.

Another equally important characteristic is the resin’s refractive index after it has been cured. The refractive index determines how much a light wave ‘bends’ when entering and leaving the surface of the resin. Ideally, it should be the same as that of the windscreen, so that any light passing through the resin – and glass – acts the same as if it were passing through glass only. This makes the resin in the damage about almost invisible, upping the game from being considered a bonus as our friend suggests.

Curing the Resin

Resin cures as the result of a photochemical process in which monomers harden or cure upon exposure to ultraviolet radiation. A specifically formulated monomer will bond with other monomers – or polymerize – when it is exposed to UV light and isolated from oxygen molecules. This UV ‘curable’ monomer has a photo initiator which absorbs UV energy and initiates a polymerizing reaction in the monomer. In order for this reaction to take place, the UV radiation must be in the correct wavelength (usually 365 to 380 nanometers) and be of sufficient intensity to completely polymerize the resin within a few minutes if not seconds when using a high powered lamp. Any aesthetic improvement is considered to be a bonus, or does he mean a fluke in his case?

As Far as Misconceptions Go…

While many claim that windscreen repair is not an exact science, the facts prove otherwise. In simple terms, if the damage looks the same after the attempt to repair it, it has not been repaired. Decades of research and development into what some people have even referred to as a black art confirms that anyone rolling out piss poor excuses and statements like the one above is insulting your intelligence. The aim of this post is to arm you with some basic facts so that you can challenge the bullshitters and if, as a result, you can use these to prove how your perfectly repairable windscreen has now been condemned as a result of incompetence, well, this in itself would be considered the real bonus.


Tailgate Glass Transplant

 

 

 

Some of the unsung work we, as windscreen fitters do, is in bodyshops (or accident repair centres). Working as the subcontractor for a crash repair garage can be bread and butter for some firms or the staple income for a lot of windscreen companies. Here is an example of a quick turnaround job: the tailgate transplant.

The new tailgate is painted as the old, crashed one is removed from the car and stored. On the day of the swap, the new painted tailgate will be hung on the car, and work to transfer all the parts begins. The bodyshop fitter will remove all the parts leaving the glass to the specialist:

Tailgate Transplant

The donor tailgate

There are various ways to remove the glass, some methods are better than others. This glass was removed with a square-profiled wire.

Heated rear windscreen removed

Work then begins or preparing the newly painted tailgate. A minimum period of 24 hours must pass after bake before a bonded application can be introduced to fresh paint. With this in mind, a few checks are still necessary to satisfy the installer that the substrate is suitable for bonding to. The new tailgate preparation begins:

New tailgate

There are many polyurethane adhesives on the market. For this job, Sika’s Sikatack Drive was used. Despite its excellent primer-less application, the manufacturer recommends use of a primer – or adhesion promoter – on freshly painted surfaces. But before that, the surface is ‘scratched’ over the bond line to provide a ‘key’ for the primer to adhere to:

Surface preparation: key

Following Sika’s guidelines, the surface is ‘activated’ as preparation for the primer, but also to remove any particles of dust or contaminants. After observing the requisite flash off time, the (black) primer can now be applied:

Adhesion promoter by Sika.

Whilst the primer dries, the glass can be prepared. This is a delicate process of cutting back the old cured adhesive and cleaning the surface. Care is taken not to catch or damage ant hardware on the glass, especially the heater elements. Again, following manufacturer instructions, the  glass  is  prepared  before  fresh  (polyurethane)  adhesive ( “PUR” )is applied. The glass is marked indicating the date, the installer’s identification as well as the corresponding batch numbers for the PUR for traceability.

Heated rear windscreen

Finally, the ‘transplanted’ heated rear windscreen:

Peugeot 3008 glass transplant

Comments and questions welcome.

Dealer Part Windscreens

 

 

 

Original Equipment Manufacturer Versus Original Equipment Equivalent Windscreens (and Glass).

“Is the windscreen Original Equipment?”

This has emerged as a common question for many motorists and a growing number of consumers. The availability of information via the internet has raised awareness among the more discerning motorists about the distinction between aftermarket and genuine glass. Windscreens have become much more complex in the role they play in a vehicle. It is much more than what the name suggests, and with the advent of driver assistance technology, the relevance of windscreen authenticity and product quality has never been so pertinent.

Whether the vehicle is new or leased, the consumer is usually told by the contracted repairer that the replacement windscreen they intend to fit will be an original equipment equivalent ( “OEE” ). However, when the fitter (or technician) shows up to replace the broken windscreen, the glass may not bear the (vehicle) manufacturer’s logo. For many years, this subject has been trivialised with what’s the big deal attitudes however, today the big question being asked – and rightly so – is, what is the difference?

OEM – Original Equipment Manufacturer. Most commonly referred to as OE parts, are produced under license from the car manufacturer, and installed in the factory when the vehicle is assembled. These parts are also sold via the vehicle’s main dealer networks as replacement parts.

Genuine Audi Windscreen

Genuine Audi Windscreen

OEE – Original Equipment Equivalent. These are parts produced for installation in the ‘aftermarket’ by third party companies. This option can also be referred to as aftermarket glass ( “AM” ). They can be produced by the same manufacturer as the OE version (but not always in the same factory using the exact same process).

What is an OEM Windscreen?

When a new vehicle is designed the vehicle maker can use an existing windscreen part from an older model, or they can create a completely new windscreen with its own unique part number. If the decision is made to create a new part, the vehicle manufacturer contracts and commissions a glass manufacturer to produce the part. These ‘authentic’ parts are installed when the vehicle is assembled. A percentage of that production run will be allocated to the vehicle manufacturer’s (usually franchised) main agents to be made available as replacement parts. OEM parts are – usually by far – the best available products.

 

Genuine Jaguar Windscreen

Genuine Jaguar Windscreen

Is an OE Windscreen the Same as an AM Windscreen?

After a new vehicle has reached dealerships and is sold to consumers, third party glass manufacturers will, sooner or later depending on any commercial or copyright restrictions, acquire and OE windscreen and reverse engineer a mould to manufacture their own aftermarket glass parts. OEE – or AM – parts are often slightly different in size; they have slight differences in the bend or curve of the glass and may also have higher distortion when viewed from an angle. All of these differences may range from negligible to discernible depending on the quality. As with most ‘copy’ or non genuine products, the more cheaper the windscreen (than the original) the more flaws you will find.

 

Removal of the Manufacturer Logo.

Some windscreen manufacturers (or even wholesalers) will remove the car manufacturer’s logo (from the windscreen) if that particular product is to be sold outside the main dealer networks (specifically by an aftermarket glass wholesaler). There may be some commercial restrictions for this in terms of authority to sell genuine parts, and some of these parts may even have been rejected by the car manufacturer. This could be down to a quality issue, or simply down to order fulfilment.

 

What are some of the Main Differences Between OEM and OEE Windscreens?

 

  1. Clarity – Windscreens ‘bent’ during manufacture will show some distortion when viewed through at an angle. This can be described as waves or waviness. Aftermarket glass is pressed, moulded, fired (and cooled) during manufacturing in a slightly different way to the original. As a result of these differences the aftermarket process can create more distortion in the glass, especially on the curved parts of the glass. Often it is noticeably more.
  2. Safety – Both types of glass will be compliant as they go through the same ‘drop test’ if they are to meet the pass criteria. When both types meet certain safety guidelines, many installation companies will push the argument that aftermarket glass is ‘as good as’ or the same as the original version but the claim is based simply on this one similarity.
  3. Hardware – such as mirror brackets, ADAS camera and rain sensor mounts, radio antennae; heated windscreen elements; navigation modules and scuttle retainers. Aftermarket windscreen manufacturers use different materials for these ancillary and constituent parts. They’re often of a lesser quality and very obviously stuck on using less effective adhesives (sometimes double sided tape). The accuracy (in their placement on the glass) can often be someway off the correct axis. It is not uncommon to have to modify some of these parts to make mirrors and rain sensors fit properly, but with many cars featuring driver assistance devices (such as Adaptive Cruise Control and collision avoidance, read the full info here) the positioning of the mounting plates and brackets are vital.
  4. Silkprint – also known as the ‘obscuration band’ or frit. Some will have a dotted border, and others will be a defined line to border the glass edge enough to primarily help protect the adhesive from UV light, and also to cover the leading edge of the dashboard or conceal pillar trims. Genuine glass may have the logo of the car manufacturer incorporated into this (such as Jeep do on the Renegade model, for example). Aftermarket glass often will show misaligned VIN notches (the small area through which the vehicle’s chassis number is visible) or the dotted area around the mirror may show some imperfections.
Aftermarket Windscreen

Aftermarket Windscreen

 

Which Windscreen Should I Choose?

Ultimately, the decision is governed by price. This may not be the you – as the car owner’s decision; it may be driven by the deal struck between the insurer (or fleet operator) and the contracted repairer. What’s more important is how the glass is fitted. Who fits the glass and to what standard is just as important as the product fitted. There are some factors to consider in making that decision: the car. Is it a specialist car? Is it a car of high value? Is it a Marque of Distinction? Does the manufacturer warranty still cover the car? If you’re claiming for the damage via your insurer, what did you agree to before policy inception? If the car is your pride and joy, would you agree to have an inferior quality replacement part fitted?

In my 25 years experience fitting windscreen and glass to cars – from everyday production cars to the more exotic and rare automobiles – the Original Equipment parts are the best available. They just fit better. The whole experience of fitting a genuine windscreen does not present any issues in that process, and there is never a call weeks or months down the line to report a mirror boss falling off for example.

If an ‘equivalent’ does not bear the car manufacturer’s logo, it is usually nowhere near as one that does.