GT3 coolant pipe issue
Discussion
Seeing the recent NBR pile-up video got me wondering just how big an problem the GT3 coolant pipe issue is. Now when I looked into this in the past I was led to believe it really is only a problem for track based cars from warmer climbs. Now this recent incident was at the NBR close to winter, so this idea clearly doesn't apply.
I spoke to a reputable specialist about this about 2 years ago and they weren't even aware of this particular problem; which I found strange as I assumed most GT3 owners would be aware.
So does anyone have any reliable data or actual experience of this problem so that current owners to weigh up the risks for themselves. Even if a pipe letting go doesn't end up in a massive pile-up, it could very quickly mean the end of a very expensive Mezger engine if you didn't notice in time.
I spoke to a reputable specialist about this about 2 years ago and they weren't even aware of this particular problem; which I found strange as I assumed most GT3 owners would be aware.
So does anyone have any reliable data or actual experience of this problem so that current owners to weigh up the risks for themselves. Even if a pipe letting go doesn't end up in a massive pile-up, it could very quickly mean the end of a very expensive Mezger engine if you didn't notice in time.
I believe the issue is related to the glue used to fix the coolant pipes.
When on track, these pipes go through rapid heating and cooling cycles and that makes the glue deteriorate... Which then causes the pipes to detach.
At least that's how I understand it.
'pinning' the pipes is one option but welding the pipes is the failsafe option.
When on track, these pipes go through rapid heating and cooling cycles and that makes the glue deteriorate... Which then causes the pipes to detach.
At least that's how I understand it.
'pinning' the pipes is one option but welding the pipes is the failsafe option.
Further reading...
D.I.Y fix
https://rennlist.com/forums/997-gt2-gt3-forum/6792...
Sharkwerks technical article
http://sharkwerks.com/porsche/technical-articles/3...
D.I.Y fix
https://rennlist.com/forums/997-gt2-gt3-forum/6792...
Sharkwerks technical article
http://sharkwerks.com/porsche/technical-articles/3...
I guess the way to treat this issue is like a ticking bomb with unknown fuse length.
I understand that some tracks in the USA require pipes to be pinned or welded. I know that JZM were Knurling the pipe ends to make an interference fit, which they believed was a better solution. I did read somewhere that 997 Gen 2 onwards had a revised "adhesive" but still seems bonkers idea to me. Maybe if engine is out for another reason then take the opportunity to fix them then.
I understand that some tracks in the USA require pipes to be pinned or welded. I know that JZM were Knurling the pipe ends to make an interference fit, which they believed was a better solution. I did read somewhere that 997 Gen 2 onwards had a revised "adhesive" but still seems bonkers idea to me. Maybe if engine is out for another reason then take the opportunity to fix them then.
I’ve been driving GT3’s at circuits all over the UK and Europe since 2000. 1000’s of laps. Lots of GT3’s at each day. In that time I’ve never seen a car experience a coolant hose issue. I’ve seen plenty blow off their inlet manifolds during a spin but no coolant pipe issues.
I’m not saying it’s not happening and that it’s not a problem - but I’ve never seen it happen.
Just to put a personal context into the thread.
I’m not saying it’s not happening and that it’s not a problem - but I’ve never seen it happen.
Just to put a personal context into the thread.
It's a strange one. The US guys seem to think it's a time bomb waiting to happen and it does seem to occur pretty regularly there but it's far rarer here. Manthey said they recommend the 996s to be sorted but the 997s hardly ever have this issue, particularly the .2 when I was asking them if it was worth getting a permanent fix and one would assume they of all people should know....
One of the pipes on my car went on the road one Sunday morning. The coolant gushes out pretty quickly but a warning beep and message came on within about a second of it happening, so you it's not as if you could keep driving unawares. Therefore there's a little bit of time to get the car stopped and turn the engine off before the temperature can rise.
The car was about 8 years old at the time and had done maybe a couple of track days in its whole life. The offending pipe was the one at the front of the engine, so inaccessible unless dropping the engine/box... I don't remember any coolant getting on the rear tyres.
The car was about 8 years old at the time and had done maybe a couple of track days in its whole life. The offending pipe was the one at the front of the engine, so inaccessible unless dropping the engine/box... I don't remember any coolant getting on the rear tyres.
Just to add more confusion wasn't the car at the ring a 991RS? Looks like it in the pics. I don't do anything like as many TD etc as SB above but I've seen 2 cars fail with coolent pipes on track. It is pot luck. I personally had mine welded when the engine came out for other works and would suggest thats the best time to do it. It's one of those things it could happen at any point. Seen a few turbos (road cars) have same issue. Also don't ignore the front hoses either as they shrink with time and can pop too. Here's a vid of what happens when one of these pipes fail.
https://youtu.be/-jG-Is8j2Gs
https://youtu.be/-jG-Is8j2Gs
Just to add more confusion wasn't the car at the ring a 991RS? Looks like it in the pics. I don't do anything like as many TD etc as SB above but I've seen 2 cars fail with coolent pipes on track. It is pot luck. I personally had mine welded when the engine came out for other works and would suggest thats the best time to do it. It's one of those things it could happen at any point. Seen a few turbos (road cars) have same issue. Also don't ignore the front hoses either as they shrink with time and can pop too. Here's a vid of what happens when one of these pipes fail.
https://youtu.be/-jG-Is8j2Gs
https://youtu.be/-jG-Is8j2Gs
Many thanks guys, this correlates with what I was thinking. From the above, there are 2x track day warriors with serious seat time in GT3's over the years and only 2 known examples. Then the odd failure here and there. German manufacturing can often have differing quality and spec for different markets for the same product. I know Slovakia did some serious testing of things like Persil, Nutella... recently and found the likes of a 10% reduction in Cocoa for the Nutella for the eastern European market and much lower quality wash powder etc. So it wouldn't surprise me if when they do a run of cars for other markets, they compromise here and there. I'm not saying that an alternative adhesive/sealant was used for these joints however the fact the Yanks have more cases leads one to question why.
I wasn't aware of the front pipes. I did wonder why when my car had a full engine upgrade, they also replaced every coolant pipe at the same time.
I wasn't aware of the front pipes. I did wonder why when my car had a full engine upgrade, they also replaced every coolant pipe at the same time.
I suspect failure rates are higher in extremely hot climates where the glue breaks down faster. My Dubai-based 996 GT3 popped a hose twice (once on track). No failures since it got welded.
I also drifted sideways on the coolant of another 996 GT3 who had popped a hose and was spinning in front of me. That was close.
Appreciate GT3s in temperate climates probably fare a lot better, but it's one of the only weak spots on an otherwise legendary car.
I also drifted sideways on the coolant of another 996 GT3 who had popped a hose and was spinning in front of me. That was close.
Appreciate GT3s in temperate climates probably fare a lot better, but it's one of the only weak spots on an otherwise legendary car.
Cunno said:
Just to add more confusion wasn't the car at the ring a 991RS? Looks like it in the pics. I don't do anything like as many TD etc as SB above but I've seen 2 cars fail with coolent pipes on track. It is pot luck. I personally had mine welded when the engine came out for other works and would suggest thats the best time to do it. It's one of those things it could happen at any point. Seen a few turbos (road cars) have same issue. Also don't ignore the front hoses either as they shrink with time and can pop too. Here's a vid of what happens when one of these pipes fail.
https://youtu.be/-jG-Is8j2Gs
My car https://youtu.be/-jG-Is8j2Gs
Just to expand & clarify, the coolant fitting inserts were welded in 2011 and all the hoses in the engine bay plus the big cast ally pipes that run down the firewall were replaced at the same time. I was the first customer to have their fittings welded, but Fearnsport have welded up quite a few more since & on some cars it has been easy to remove at least one of the old inserts due to the glue having failed. There was a pink tell-tale residue where it had been leaking for some time.
In 2014, a short connecting rubber hose that joins one of the big cast ally pipes (as above, previously changed) to another hard pipe that runs in the tunnel under the car shrank enough to pop off and cause the coolant to dump. I chose to replace _every_ rubber hose forward of the engine bay (and there are a fair few - see below). It was a hugely costly job, not just due to the expensive hoses but also the hours it takes to dismantle the front end to get to the damn things. Many of the old hoses were only just hanging on due to shrinking over the years, so be aware that to really cover the bases, you need to be looking at replacing all of them at some point.
Edited by nxi20 on Sunday 19th November 15:21
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