TexasPorschelover

I was basically trying to force my Porsche mechanic into doing it on mine. He said 99.9% of the time it'll leak first so there is a warning and only once has he seen an actual failure. He said given I will run it very hard occasionally not to do it. If I were tracking often.... different.... perhaps different calculus. Sounding like a reasonable approach. From the way people describe the failure on RL you would think its just some out of the blue catastrophic failure. Wonder how true that is. My mechanic say's no. Glue wears out and leaks form under pressure first.

pissedpuppy

absolutely

DKP 97 C2 Coupe

This OP has brought up some interesting responses. As someone who owns a 997.2 GT3 and is also CDI for our PCA region please let me weigh in with the following basic facts:

• A coolant pipe can fail without any warning (leaking). A friend had a tube fail while on the way to the dealer to have the tubes welded .
• The above brings up a good point: it seems as though these discussions are all about having something happen while on the track....but very bad things can also result (not only to you but other motorists) if it fails while on the street
• Our region, as well as a number of other PCA regions, require proof of a permanent repair being performed before a Mezger-engined car is allowed on the track. It is true, of course, that in the context of an autocross the odds of you hitting something are greatly reduced as compared to a traditional track event.
• The only proper repair is to have the engine removed and the tubes welded in place by someone who has considerable skills at TIG welding aluminum.

Bottom line: as much as this stinks and that Porsche should have used a much more robust method to attach the coolant tubes to the manifold, the only responsible course of action for someone who owns a Mezger-engine, liquid-cooled car is to drop the engine and have the tubes welded. This of course includes 996 and 997 GT2/3's, 996 Turbos, and 997.1 Turbos....

bweSteve

DKP,... as I'm still considering having this done, can I ask whether you believe that pinning the tubes is "not" a "proper" repair/fix? Not from a PCA autocross perspective,.. but more from your experience in possibly seeing "pinned" tubes fail.

I ask because you specifically italicized "proper", and mention to have it "welded" twice.

Thanks

joejenie

I've heard pluses and minuses about welding vs pinning. I think at the end of the day, they both are good and better than nothing. You need a very good welder to do aluminum right. My local shop will only pin.

bweSteve

right on joe. that's kinda why I'm asking. I've done some limited welding over the years, and taken a full day training with both classroom & hands-on,... and light weight, thin aluminum TIG welding is an art form. Literally not something I would just hand my water pump & recently purchased sharkwerks tube inserts to anyone. I would need to SEE their handywork first. Whereas the pinning seems like a less-risky proposition when you're walking into your local Indy for the fix.

joejenie

You should also get the two elbows from Sharkwerks while the engine is out and replace them as part of this. Probably two of the most important things to fix. Of course, while the engine is out, hoses, water pump and anything else that looks worn should be replaced. Good time to do clutch and LSD as well. Good luck! I just got mine back from the shop about a week ago from doing all of this stuff.

DKP 97 C2 Coupe

Mussl Kar

My Kermit never had it done and has run as many as 35 autocross days a year since new in 2007. Retired it mid 2016 but will bring it back next year. Not even on the local regions radar AFAIK at autocross.

DKP 97 C2 Coupe

While it may indeed be the case that organizers of AX events don't know and/or don't care about this issue with our cars that doesn't change the fact that "it's not a matter of if but when". The notion of having your defense be: "well, I've done a ton of events with my car and haven't had any trouble" is, to me, analogous to "I've never had an accident; I don't see the need to wear a seat belt". One of your tubes could fail on the way to the event, possibly sending both you and the next couple of cars that happen to follow you on the off-ramp of the highway into the guardrail. I am not being dramatic; there have been serious accidents caused as a result of a failure during street driving.

Only each Mezger-engined car owner can decide for herself if continuing to operate a car with a well-documented and obvious safety flaw while choosing to not get a proper repair done is in both her and anyone who may be behind her best interests.....and we, as a PCA region who conducts three HPDE events over the course of the driving season, have taken this decision out of the owner's responsibility as we want to eliminate any possibility that a failure could occur at one of our events.

IMHO, anyone who has the means to operate one of these very special machines also has the means to prevent an accident that might occur as a result of an obvious poor decision by Porsche in terms of attaching the coolant tubes to the coolant manifold when they adapted the Mezger engine for liquid cooling.

Cheers, David

lmnsblu355

Do you have any first hand knowledge of this actually happening?? I've been following this issue since I got my 997.2 GT3 6 years ago and have not seen any posts or heard of any failures of pinned tubes. Once the pinning is done, it stabilizes the interface and the epoxy should not fail. The epoxy acts a grout. I pinned my tubes engine-in at a cost of less than $50 using the method described here on Rennlist. No leaks, no issues.

I have however seen posts related to porous welds leaking. Welding requires engine out and a highly skilled welder, ie $$$

This is a low pressure system. Welding is overkill IMHO and the expense likely keeps people from doing the right thing. Pinning with the engine-in works and can be done on all 997.1 and .2 GT3/RS by any mechanic or experienced DIY'er.

https://rennlist.com/forums/997-gt2-...n-the-car.html

GSM

As a BMW guy, the welding/pinning issue is less applicable to me. That said, I'd suggest that track cars use water & water wetter in place of traditional anti-freeze. In case of a catastrophic leak the resulting liquid on track is substantially less slippery than anti-freeze.

And if you are in a cold-weather climate, be sure to either drain the water for the winter and replace with anti-freeze, or store the vehicle in an environment where you can be confident that temps will never drop below freezing, even when power is out.

G

Marv

133K miles on my 2004 GT3 with only one pipe welded so far (top one came apart a few years ago).

I don't worry about auto crossing the car in this condition. It's pretty stress-free compared to lap after lap running near the car's limit. I'd never consider running on a track without fixing the coolant pipes!

The worst that can happen on an autocross track is making an embarrassing, but memorable, mess and having to flatbed your car away. No one's on your butt and going to spin and eat a cone or two.

Marv

My shop is adamant about welding the pipes and not pinning for the very reasons cited above. Is that really true? I don't know. Seems possible. Ideally, if you are going to pin, then pull the buggers out, clean, re-glue, and then pin. I saw a video where one shop knurls the fitting, epoxy is added, then it's driven in.

The downside to welding is possible pin holes. The one that I had welded hasn't leaked, so I probably will have the rest welded when I drop the engine to do the clutch.

I have no desire to sell my car, so this is just the first 133K miles for me. Welding may not be overkill for my situation. I can't see epoxy holding up for 250K miles.

lmnsblu355

Pulling the tubes out and replacing the epoxy is not necessary unless the tube is already loose. Pin before there is a problem and forget about it. The epoxy in your engine is holding even without the pinning, Why do you think the epoxy with a pinned tube will leak??
If after pinning it develops a small, slow leak, which it probably wont, THEN pull the tubes, clean, re-epoxy and re-pin.(OR spend $$$ to weld) I still haven't heard a first hand report of a leaking tube after pinning.

Pinning engine-in is cheap and WILL prevent catastrophic loss of coolant.