New windscreen seems different

[Grandeman Avid PP Poster! Find all posts View Profile Close Grandeman]

Just got a new windscreen fitted - Windscreens O'Brien.

The fitting looks fine and very neatly done. However, I notice that a LOT more engine noise gets into the cabin. It sounds as if one of the doors isn't quite shut with the amount of noise that now makes it inside.

There doesn't seem to be any wind noise, so I don't think it's a sealing issue - I'll verify that with the next car-wash though.

Could it have anything to do with maybe a thinner grade of glass being used? I'm stumped...

[John Member Find all posts View Profile Close John]

Gidday Grandeman,

As an ex-auto glass person, I doubt that your glass is thinner than standard. That's because the vehicle is complianced with the factory glass. That should be around 6.76mm laminated. That's 2x3mm glasses with a .76mm interlayer. This is particularly important if the glass is considered to contribute to the structural integrity of the vehicle.

I suspect you have one of 3 possibilities:

1. The seal is not complete (as you wrote). A car wash might not give you any evidence. I'd direct a hose all around the windscreen edge. The trim strip might still mask a leak however. I know this sounds stupid, but you might be able to hold a speaker (playing music or similar) around the edge of the glass outside, while you sit inside with the windows closed. Where the sound comes in is your leak. We used an ultrasonic detector when i was doing windscreens.

2. The glass is sitting on the scuttle and sound/vibration is being transmitted into the cabin from there. This occurs when the glass was not installed with the proper rubber blocks to support it from the scuttle, or they were removed while the urethane was still soft, allowing the glass to drop in the aperture. Alternatively, an edge of the glass could be touching somewhere on the aperture where it sits. This should be evident if the weather strip is showing signs of deformation or sticking out (see next para).

3. The weather strip around the glass is sitting proud of where it should, creating wind noise. This sometimes happens when the fitters recycle the old strip instead of installing a new one.

Hope this helps.

[Grandeman Avid PP Poster! Find all posts View Profile Close Grandeman]

Thanks very much John - I really appreciate your expert input.

I'll go back to O'Briens to see what they say about it.

[Grandeman Avid PP Poster! Find all posts View Profile Close Grandeman]

The answer, it seems, was that an air bubble compromised the seal - the solution was to take the windscreen off and reinstall.

Problem solved.

O'Briens were good about it and did so no questions asked.

Phew!! What a relief.

John, you were spot on in your assessment. Once again, thanks for the helpful advice.

[John Member Find all posts View Profile Close John]

Gidday Grandeman,

Glad I could be of help. O'Briens are pretty reputable (they were our opposition back in the good old days).

Usually when there is an air bubble, it comes out of the urethane cartridge. Normally the installer will hear it - it makes a "cracking" sound as it passes through the nozzle. Sometimes you don't hear it. There aren't supposed to be air bubbles in the cartridges, but sometimes there are....

The other reason you can get a bubble is if you close all the doors with the windows up before the urethane has set - the pressure inside the car has to go somewhere - and partially "pops" or blows out part of the urethane. Very undesirable because windscreens fixed in urethane actually form part of the structural integrity of the roof turret (believe it or not!)

[Grandeman Avid PP Poster! Find all posts View Profile Close Grandeman]

Expertise such a yours, John, make this forum such a great place to exchange information and helpful advice.

It's amazing how quick the whole windscreen replacement process is now.

I remember when my Dad had a broken windscreen, when I was a youngster, and the car was off the road for at least a whole day (if not two) to get a new screen put in - and the mess they made whilst doing it!

Things have come a long way...

[joedan Junior Member Find all posts View Profile Close joedan]

Last week had a huge rock hit my windscreen and $120 dollars later got it fixed, luckily only the size of a 10c piece.

This morning, going along a semi rural road, another car throws up a huge boulder, whack in the middle of the screen, twice the size of a 50 cent piece.

The wife stuck a Novus sticker on to protect it but now the crack has just gone through to the dash.

Looks like a new windscreen is required, the car is only 5 months old.

A 120 D4D.

I read somehwre in an article that the D4D uses acoustic glass? Is that correct? Are the windscreens any different to the other 120's or is this just marketing crap?

[Grandeman Avid PP Poster! Find all posts View Profile Close Grandeman]

Don't know about that...

But I did ask the O'Brien guy (who fixed a 10c piece size chip in my new screen two weeks ago), whether I could buy a heavier grade windscreen (ie thicker glass), and his response was "no".

[joedan Junior Member Find all posts View Profile Close joedan]

From the Toyota Presskit regarding the new D4D...

http://www.pressroom.com.au/press_kit_d ... &kitID=208

"Along with the new turbo-diesel engine, the diesel models gain acoustic windscreen glass and new sound-absorbing material under the instrument panel to reduce noise, vibration and harshness. "

Might have to make some queries...

[joedan Junior Member Find all posts View Profile Close joedan]

Could anyone please with a late model NON D4D compare Windscreen identification tags to see if they are similar?

Can't really tell if it's any special or just a standard Prado windscreen.

[John Member Find all posts View Profile Close John]

joedan,

I worked in the windscreen industry in a previous life. The various markings on the etched label really only tell you 1. Who manufactured it (Asahi Glass), 2. It is laminated safety glass (Lamisafe) and the rest of the markings are the various approvals for the countries the glass is sold, and their licence number. Sometimes the manufacturing pland number is coded on the glass.

I find it very difficult to believe that there could be anything special about the glass to make it "acoustically better" than a standard windscreen. The only way it might be more acoustically quiet could be due to any or all of the following factors being different to the earlier models:

1. the mounting system (urethane) may have been slightly revised;

2. The filler strip (trim around the glass) may have been redesigned to generate less wind noise;

3. Windscreen glass is typically 6.76mm thick - that's 2x3mm glasses and a 0.76mm interlayer. Some glasses can be made thinner (like the old Camira's in the 80's) and still be compliant. Perhaps the earlier Prado windscreens were slightly thinner and the manufacturer has now gone to a thicker glass/interlayer combination. One means is the addition of a second interlayer and third glass layer. That would certainly reduce the noise, but could ordinary people like us tell the difference? This would also make the glass DAMN expensive.

I reckon it's a Toyota spin-doctor at work.

[joedan Junior Member Find all posts View Profile Close joedan]

Thanks very much for the info John.

From your experience, are all automative glass fitters the same? i.e. use the same quality aftermarket glass, adhesive etc?

I made some calls today about Prado Windscreen replacements..

A local discount windscreen mob want $195, Windscreens Obrien are asking for $265 & Novus $258.

$195 sounds good , however can't understand the huge price difference. Both are covered with similar warranties?

[John Member Find all posts View Profile Close John]

joedan,

windscreen fitters are like any other trades persons. Some good, some bad.

As for quality of glass, that can vary enormously. One particular Australian manufacturer is famous for having the cheapest windscreens - but he was also famous for record numbers of delamination claims under warranty, and poor fitment of the glass (ie incorrect shape). One U.K. manufacturer with the same name as the expensive crockery has a similar reputation for delaminations.

Pilkington ACI were really at the forefront of quality and innovation when I was in the industry. They had extensive R&D facilities and created a number of new production techniques, such as tong-free toughened glass. IMHO their glass quality was superior to O'Brien, who came a close second. Pilkington also had almost exclusive market share for the supply of OEM glass to Ford, Holden, Toyota (Oz production) and Chrysler/Mitsubishi.

I don't know what the quality of Chinese glass is, as I'm no longer in the industry. Hopefully it would be better than some of the other products they manufacture.....

Fitting-wise - "stick-in" windscreen installation techniques have evolved enormously. The earliest (XA-XF Fords, and HQ-HZ Holdens) used a butyl tape with a wire running through it which was connected to a transformer to heat it up and partially 'melt' the tape. That was okay, but after a while the tape went hard and partially separated from either the glass or aperture, causing huge leakage problems. Often the glass separated completely from the tape and the only thing holding it in the aperture was the trims!

Since then, with the advent of "structural integrity", where the glass is actually used to strengthen the turret (believe it or not), I remember watching videos of rollover tests with glued in windscreens. Often the car would roll a couple of times before the windscreens broke, and in all instances the windscreen prevented or reduced the intrusion of the forward/rear turrets into the passenger zone. But I digress. The aforementioned butyl tape was basically useless, and was never designed to add strength. The only way to facilitate this is by a fairly rigid polyurethane glue, such as Sikaflex. When applied correctly this stuff is enormously strong at bonding glass and metal.

Some windscreen replacement companies also used a neutral-cure silastic as a substitute, which IMHO does not have as strong a bond. Remember, this stuff not only has to keep the water out but contribute to the strength of the car! Sikaflex and like-branded urethanes require etching of the surfaces to be bonded (with a primer). This is a key to overall adhesive strength and longevity of the bond.

The disadvantage of stick-in techniques is time. Typically you need 24 hours for the urethane to go off and reach full strength. I would be loath to drive my car out of a windscreen fitters on the same day because at best you might induce a few small leaks, at worst a complete separation of the glass (particularly if you slam a door shut with the windows up). And you don't have all those big chunky trims to stop it flying out :lol:

Sorry to waffle on. Price is often linked to overheads. O'briens will probably charge you more, because they have higher overheads than an independent. But I bet they'll match the discount price though. :wink:

I wouldn't say you'll get a lesser job done by the independent. He was probably trained at O'Brien (small industry). There may be a difference in brand name on the glass but that isn't always the key reason for price differences.

There are a lot of other factors that can vary the price. I won't waffle on much longer..... Toyota might specify a new plastic trim. Some fitters may do it, others might re-use the old one (which may not be designed to do so). Toyota might specify a specially-shaped extruded rubber dam (to hold the urethane in shape), where some fitters may use a cheap foam tape (like you see on your home doors to stop noise or drafts).

The best advice is ask questions. Good luck!

[joedan Junior Member Find all posts View Profile Close joedan]

Thanks again John.

It's great to be able to ask someone in the know.

[hoppy Senior Member Find all posts View Profile Close hoppy]

Gday John

I used to work for a windsceen company back in the mid 80s at Artarmon and Brookvale in Sydney. You definately know you stuff. Most of my winscreen replacements back then was with the heated butyl tape and in summer we didnt even bother to heat it up !!! The urethane method was quite new back then, although becoming more common.
Nothing much to add after your comments, just the fact you took me back 20 years. I now work in the TV industry as a news cameraman.... go figure!!