GT1 block owners - catastrophic coolant leak prevention
Discussion
Theres been a bit of discussion here in recent times around how to address a problem common to all GT1 block engines.
The issue is that Porsche have employed fisher price engineering to bond together metal to metal coolant pipes with an epoxy/glue, which has in numerous instances (e.g. theres a 12 page list of affected US cars on rennlist) led to the metal pipes coming apart/popping out as the glue breaks down (heat-cycling) dropping coolant all over the engine and floor. You can exect a multi-thousand pound bill to fix if this happens.
Typically, the pipes will come apart when driving, on track or road, leading to potentially lethal circumstances of coolant being dropped all over the track/road, with the affected car and any following, skidding out. This has happened to 996 and 997 gt3/turbo/gt2 models.... there does not seem to be any link to mileage or use, sub 20k mile 997.2gt3's and 100k mile 996turbo's can be equally affected.
Given my own car (996tt) was recently at Fearnsport for a new clutch, I took the opportunity to ask Matt to provide a preventative fix for this problem. The coolant pipes total 7 (I think), most of which are on the bracket which seats the heat exchanger, and are only accessible with the engine out of the car - and if you want to do them all as below, you'll need to strip the top end of the engine.
So, to the fix... firstly, this can only be done as an engine out job - the plan was to remove all of the glued in metal pipe inserts and replace them with custom fabricated metal inserts with flanges to allow the pipes to be welded together to offer a permanent seal.
Porsche glued insert on the far right & Fearnsport's newly fabricated inserts with flanges (ready to be welded) to the left:
Bracket (and all other parts as nec) steam-cleaned before work begins (cool machine !!)
Glued inserts removed and the hole cleaned up from the epoxy residue to ensure perfect fit before new pipes welded in:
Bracket with new metal inserts, ready to be welded...
Welded in.... as it should have been out of the factory !!
There are a couple other inserts not pictured which are harder to get to but the gist of the fix is the same - it just comes down to how much £££ you are prepared to incur to address all the glued insert locations
I would say the above is something to consider if your engine is ever out, and whilst at it, its worth replacing various water hoses and the coolant header tank also...
Or maybe... just maybe, I didnt need to do any of it and spend too much time on the forums
Big thanks to Matt for the above, and as usual for going above and beyond the call of duty & spending his morning (unsolicited) machine polishing my car in a effort to bring my cloudy paintshield back to life - was a fantastic suprise
![](http://thumbsnap.com/sc/kAC0Zc4B.jpg[/img]</a> <a href="http://thumbsnap.com/cYzdnzRT" Target="_blank">[img]http://thumbsnap.com/sc/cYzdnzRT.jpg[/img]</a> <a href="http://thumbsnap.com/cYzdnzRT" Target="_blank">[img]http://thumbsnap.com/sc/cYzdnzRT.jpg)
The issue is that Porsche have employed fisher price engineering to bond together metal to metal coolant pipes with an epoxy/glue, which has in numerous instances (e.g. theres a 12 page list of affected US cars on rennlist) led to the metal pipes coming apart/popping out as the glue breaks down (heat-cycling) dropping coolant all over the engine and floor. You can exect a multi-thousand pound bill to fix if this happens.
Typically, the pipes will come apart when driving, on track or road, leading to potentially lethal circumstances of coolant being dropped all over the track/road, with the affected car and any following, skidding out. This has happened to 996 and 997 gt3/turbo/gt2 models.... there does not seem to be any link to mileage or use, sub 20k mile 997.2gt3's and 100k mile 996turbo's can be equally affected.
Given my own car (996tt) was recently at Fearnsport for a new clutch, I took the opportunity to ask Matt to provide a preventative fix for this problem. The coolant pipes total 7 (I think), most of which are on the bracket which seats the heat exchanger, and are only accessible with the engine out of the car - and if you want to do them all as below, you'll need to strip the top end of the engine.
So, to the fix... firstly, this can only be done as an engine out job - the plan was to remove all of the glued in metal pipe inserts and replace them with custom fabricated metal inserts with flanges to allow the pipes to be welded together to offer a permanent seal.
Porsche glued insert on the far right & Fearnsport's newly fabricated inserts with flanges (ready to be welded) to the left:
Bracket (and all other parts as nec) steam-cleaned before work begins (cool machine !!)
Glued inserts removed and the hole cleaned up from the epoxy residue to ensure perfect fit before new pipes welded in:
Bracket with new metal inserts, ready to be welded...
Welded in.... as it should have been out of the factory !!
There are a couple other inserts not pictured which are harder to get to but the gist of the fix is the same - it just comes down to how much £££ you are prepared to incur to address all the glued insert locations
I would say the above is something to consider if your engine is ever out, and whilst at it, its worth replacing various water hoses and the coolant header tank also...
Or maybe... just maybe, I didnt need to do any of it and spend too much time on the forums
Big thanks to Matt for the above, and as usual for going above and beyond the call of duty & spending his morning (unsolicited) machine polishing my car in a effort to bring my cloudy paintshield back to life - was a fantastic suprise
Edited by ZeroH on Sunday 20th November 00:48
Sandy59 said:
Nice write up. Just wondering if there's any recorded cases of this happening in the UK or indeed Europe, could it possibly be related to the higher ambient temps in many parts of the US ??
Yep, happened to a friends x50 and to a chap I met at the ring 2 years ago. Lots and lots of steam is a give away 
P.s how's miras? I was in zanderbar thursday night, next time I'll buzz you if you fancy a shandy.
Edited by VonSenger on Sunday 20th November 08:43
VonSenger said:
Sandy59 said:
Nice write up. Just wondering if there's any recorded cases of this happening in the UK or indeed Europe, could it possibly be related to the higher ambient temps in many parts of the US ??
Yep, happened to a friends x50 and to a chap I met at the ring 2 years ago. Lots and lots of steam is a give away P.s how's miras? I was in zanderbar thursday night, next time I'll buzz you if you fancy a shandy.
Edited by VonSenger on Sunday 20th November 08:43
I'm fully welded up using the original Porsche fittings here and have been for a while.
IMHO people need to seriously think about this for their own and others safety, especially if they run coolant, if nothing else.
If these let go they dump coolant right onto the wheels and you will spin.
If they let go everyone else on track has a problem too.
IMHO people need to seriously think about this for their own and others safety, especially if they run coolant, if nothing else.
If these let go they dump coolant right onto the wheels and you will spin.
If they let go everyone else on track has a problem too.
Sandy59 said:
Nice write up. Just wondering if there's any recorded cases of this happening in the UK or indeed Europe, could it possibly be related to the higher ambient temps in many parts of the US ??
It's happened to leigh996tt on here as well. All sorted by SCOM, without removing the engine I believe.
Interesting and informative and another scary story surrounding the 911.
Makes me question though, with the 'issues' with the 996 and 997 engines and now this on an engine I've read time and time again is 'bullet proof' and the 'one to have to eliminate any possible engine problems', do Porsche actually employ engineers or simply people who know f-all about internal combustion engines.........or (only playing devils advocate here), is this yet another tale of an issue that can happen, but is highly unlikely to happen to 99% of owners, therefore it's simply very, very bad luck - wrong place, wrong time etc.
However, on the assumtion this is a real problem, it seems to me that these design faults we are all hearing about on all models can cause very, very expensive catastrophic failures and therefore in a normal working environment someone's head should roll.
Makes me question though, with the 'issues' with the 996 and 997 engines and now this on an engine I've read time and time again is 'bullet proof' and the 'one to have to eliminate any possible engine problems', do Porsche actually employ engineers or simply people who know f-all about internal combustion engines.........or (only playing devils advocate here), is this yet another tale of an issue that can happen, but is highly unlikely to happen to 99% of owners, therefore it's simply very, very bad luck - wrong place, wrong time etc.
However, on the assumtion this is a real problem, it seems to me that these design faults we are all hearing about on all models can cause very, very expensive catastrophic failures and therefore in a normal working environment someone's head should roll.
Hi,
The modified fittings you have had fitted look very sharp on the ends ? The piece that the jubilee clip would secure against should be more rounded like the original fitting or it can cut through the pipe work. Maybe it is smoother than it looks but it looks very pointed and sharp.
I have left mine alone for now as i have not got enough info on this failure to see a pattern, if it is an age related failure or is it just tracked cars..? Do you ever see cup engines doing this ?
Mike
The modified fittings you have had fitted look very sharp on the ends ? The piece that the jubilee clip would secure against should be more rounded like the original fitting or it can cut through the pipe work. Maybe it is smoother than it looks but it looks very pointed and sharp.
I have left mine alone for now as i have not got enough info on this failure to see a pattern, if it is an age related failure or is it just tracked cars..? Do you ever see cup engines doing this ?
Mike
Grub screw will physically prevent the fitting popping out but won't stop the leak. The bonding agent also provides the seal so when it goes this is lost.
Given it all needs to be removed to tap or weld, it makes more sense to weld and do it once.
Mike, it seems a heat versus time thing though the more heat the less time going by the 997 that are also losing some.
Cups run cooler than street cars. Bigger rads and no stop/go traffic. Plus they don't run as long. 2001 cars are often on 16,000km on the odo.
They also don't run coolant and most are welded.
They also see much more regular maintenance.
To do the pipes on the water pump you don't need the engine out. To do the rest you do indeed.
The cups from 2010 are completely redesigned in the places worst effected
Given it all needs to be removed to tap or weld, it makes more sense to weld and do it once.
Mike, it seems a heat versus time thing though the more heat the less time going by the 997 that are also losing some.
Cups run cooler than street cars. Bigger rads and no stop/go traffic. Plus they don't run as long. 2001 cars are often on 16,000km on the odo.
They also don't run coolant and most are welded.
They also see much more regular maintenance.
To do the pipes on the water pump you don't need the engine out. To do the rest you do indeed.
The cups from 2010 are completely redesigned in the places worst effected
Edited by fioran0 on Sunday 20th November 10:33
Sandy59 said:
Nice write up. Just wondering if there's any recorded cases of this happening in the UK or indeed Europe, could it possibly be related to the higher ambient temps in many parts of the US ??
Yes, theres a fair few cars here that have had this problem - I've seen cars on ramps which have suffered this problem.Greg66 said:
Interesting. How much is the complete fix, replacing all the old joints.
Strange as it sounds I'm not sure as this was just part of a lot of other work I was having done..... machining the new parts and having the welding done is not expensive however.... few hundred quid, its the labour to get to them all that hurts. HoHoHo said:
Interesting and informative and another scary story surrounding the 911.
Makes me question though, with the 'issues' with the 996 and 997 engines and now this on an engine I've read time and time again is 'bullet proof' and the 'one to have to eliminate any possible engine problems', do Porsche actually employ engineers or simply people who know f-all about internal combustion engines.........or (only playing devils advocate here), is this yet another tale of an issue that can happen, but is highly unlikely to happen to 99% of owners, therefore it's simply very, very bad luck - wrong place, wrong time etc.
However, on the assumtion this is a real problem, it seems to me that these design faults we are all hearing about on all models can cause very, very expensive catastrophic failures and therefore in a normal working environment someone's head should roll.
In the US, they have talked about class action against Porsche for this design fault. The trouble is if Porsche fix it under wtee they simply re-glue the metal parts back together... so problem is not solved. Makes me question though, with the 'issues' with the 996 and 997 engines and now this on an engine I've read time and time again is 'bullet proof' and the 'one to have to eliminate any possible engine problems', do Porsche actually employ engineers or simply people who know f-all about internal combustion engines.........or (only playing devils advocate here), is this yet another tale of an issue that can happen, but is highly unlikely to happen to 99% of owners, therefore it's simply very, very bad luck - wrong place, wrong time etc.
However, on the assumtion this is a real problem, it seems to me that these design faults we are all hearing about on all models can cause very, very expensive catastrophic failures and therefore in a normal working environment someone's head should roll.
The whole "bullet proof" comment is banded around a lot about the GT1 block engine and I think only really relates to the bottom end which if tuned properly can take a LOT of power stock.... the auxillaries of the engine and other design features such as this mean that this engine is a lot of things, but "bullet proof" aint one of them !
VonSenger said:
Well my 996tt was highly modified with countless track and ring days plus thousands of road miles, no problem with coolant at all.
Indeed, and there are lots of engines out there with 100k miles that have never had this issue... but its the randomness of affected cars that was my concern.... ironically, my pipe inserts were pretty well stuck in and took fair bit of effort to remove, so I may not have had any issues any time soon either, but my engine was out so I considered it cheap(ish) insurance to do. VonSenger said:
Well my 996tt was highly modified with countless track and ring days plus thousands of road miles, no problem with coolant at all.
It's just one of those problems that might never occur during ownership but if it does can be very costly.Prevention is better than cure.
Nice write up.
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