Dan@SharkWerks

Hi guys,
I cross-posted this from the GT3 section but this issue applies to 996 GT2/GT3 models as well so I thought it would be a good idea to post here.

Some of you may be aware of coolant pipe issues on GT1-block equipped models (GT3, GT2, Turbo), where coolant pipes come apart while driving and the rapid loss of engine coolant can cause spins/crashes at race tracks when slippery coolant sprays all over the rear tires.

The problem exists on the GT1 motor because there are a couple coolant pipes in these motors that are not a single cast piece: the larger cast pieces have extruded inlet/outlet tubes that are connected using an adhesive. There is no metal-to-metal friction or press-fit to keep these tubes in place, so after enough heat cycles the adhesive will soften/loosen up and the tube will come out of the cast block (with the hose still attached), resulting in a rapid loss of engine coolant.

Regardless of how the vehicle is driven, it seems this problem may eventually effect all 996/997 Turbo, GT2 and GT3 models including the 2010+ GT3 and GT3RS.

We have heard of many cases of this, and in fact the last time we were at Infineon Raceway, Alex and I were talking to someone about it when the exact problem happened to a 997 GT3 right in front of us -- a large steam cloud evacuated the rear of the GT3 and it spun on the hairpin! Luckily he missed the other cars and the barriers.

Here's a video showing how the tube comes apart:
http://www.youtube.com/watch?v=RH56CkzC-QE

Here's a diagram showing where the problem happens on 997 GT3 models:


Here's a picture from a 996 Turbo's coolant pipe. Both of these tubes you see are slip-fit into the cast piece and fixed in place using an adhesive:



We first saw this in early 2006 when we started building 996 Turbo engines. In fact, our 996 GT3 suffered from this exact problem earlier in its life.

James has a technique for fixing this, something we do for all 3.9L motor builds and any time a GT1 motor is removed from the car.

This week we had a 2011 GT3RS (project that was documented earlier) whose lucky owner will have plenty of track time with her. He decided that rather than wait until it might happen, he would rather be on the safe side and fix the problem now, preventing a scenario where the coolant might cause a high speed crash at a local track.

The bumper is removed exposing the Shark Werks GT3 Bypass Exhaust:


And despite the car's super low mileage, its factory fresh and perfectly running motor is removed from the car:





With the motor removed from the car, James locates each of the potential problem areas and drills a small hole through the cast piece and into the tube (that normally would come flying out at some point in the future). Then he threads a bolt through both pieces and using loctite secures the bolt in place. This locks the tube together, preventing it from coming apart regardless of heat cycles.





The coolant pipes will now act as a single piece.


All the tubes are buttoned up...



And the motor is lifted back into place, the remaining details addressed.



And here she is, now ready for an enjoyable weekend around the track at 8000 RPMs.




For more of this car, check out the whole project here.

4porsh

Do you drill and bolt all 6-8 fitting on the 996GT3?

Can this work be done by your shop in one day from start to finish?

What is the cost? PM me if you must.

Thanks,

Joe

FFaust

Thank you Dan. This is a truly ubiquitous problem; we've all seen it or experienced it first hand I'm sure.

While talking to Alex last week, the topic came up as I wondered aloud about the logistics of sending in the various manifolds for you guys to do your magic. But, the logistics would be complex, the cost too high, and the hassles of crossing the US/Canada border excessive.

However, reading your post just now, inspiration hit. Here is what SHARKWERKS needs to do:

- You need to build and sell a kit with hardware, sealant, and clear instructions so that owners of GT1-blocked cars WORLDWIDE could carry out the modification locally. Heck, you could even include drill and tap As far as I am concerned... name your price!

Who knows if this will be a huge money maker but I doubt that it will cannibalize your local business, so there is no downside for you. Plus, if nothing else, think of the goodwill such a move will create and it would certainly, ONCE AGAIN, put SHARKWERKS at the top of the Porsche Performance supplier list.

You guys have my address, so please ship me the first kit

mkk62

i'm in for a group buy

FFaust

I just e-mailed my order. Don't snooze

RJFabCab

That's an interesting approach. Perhaps the fitting won't let go with that screw in there, but have you had any slow coolant leaks when the adhesive degrades?

This looks to be much quicker than a weld job, and I hope it is as effective.

GT1s and coolant blowouts... how many times do we need to see it???!!! C'mon, Porsche!!!

Rob S

Do you remove the coolant hoses before you drill? How do you control metal chips? I'm concerned about metal chips getting loose in the coolant system if you don't open it all the way up and clean it out. Do you use a through bolt (or screw) in each case? If so, then the bolt or screw must extend through the coolant channel and it will cause a certain amount of restriction. Do you think that could be a problem? And aren't you concerned about about leakage from between the existing coolant pipe and the cast manifold that it's glued into?

452gt3

You need to pull the engine to get to all 8 of them, just as easy to weld them and not worry about future leaks.

Dan@SharkWerks

Hi Joe, correct on all fittings, the job takes about 2-days of shop time. I sent a PM with pricing.

If only the job itself was as simple as the parts required eh? We can help either way, just let me know.

We have not seen coolant leak through the adhesive, only the adhesive failing to the point where the tube is ejected.

Yes, the hoses are removed. Since most of the drilling (until the hole punches through the other side) happens on the outside of the motor the chips are going out and we clean them with a shop vac. When the hole goes through, we clean from the inside. There is minimal if any significant metal chips left by this point, not enough to effect the cooling system or damage anything.

Yes we do use a bolt in each case, the bolt is approx 10mm, the right size to just barely clear the tube on the other side. It would stick out only a very tiny amount into the inlet/outlet tubes, not enough to effect the flow.

We have not seen coolant leak through the adhesive yet, it seems that's not the issue necessarily, there's plenty of adhesive and it does not dissolve (it softens and acts like an o-ring to seal between the tube and casting), it just won't hold that tube alone anymore.

FFaust

Dan, thanks for posting all the answers above.

I've just sent you an e-mail and Alex has indicated in the 997 section that he was looking into it and would talk to James...

Rob S

Dan,

Thank you for clarifying some of this. I still have a few questions, though.

I hadn't realized that you were using a screw that only extended in a short distance and secured one side of the tube -- I thought you were using a much longer screw that crossed clear through each coolant channel and extended into the other side of the casting. With only a short screw, I'd agree that blockage is at a minimum. However, I would think that the asymmetry of that arrangement, which tends to clamp the tube to the side of the casting nearest the screw, may tend to open up a gap on the other side. Could this make for a leakage pathway between the tube and the sealant on the other side?

Are you using a nut on the inside to secure the screw or is the screw tapped and threaded into the tube? With a nut, I can see how the thread locker would be vital to keep the nut from getting loose in the cooling system. If there is no nut, is the tube thick enough to be tapped? Or does it even need to be tapped? I wonder if the screw were used as a setscrew, with no penetration of the tubing, if that would be sufficient to hold the tube in place. Maybe that's what you're doing already. Whether the screw is used to clamp the tube to one side of the casting (as with a nut) or as a setscrew to push the tube toward the other side of the casting, I would think there would still be the issue of a possible leak path on one side of the tube or the other.

I'm interested by your comment that the existing sealant or glue is adequate to prevent a leak (from your experience), but that it's not adequate to retain the tube fitting. It makes some sense that this could be true, but doesn't the bolted connection, for several reasons, seem more prone to leakage than a welded one?

Can you explain why you don't just weld them? You certainly have the facilities to do that, and you'd have the engine out anyway. Is it just that much more work to weld and not worth the cost and effort in your mind? Or is there some other drawback to welding that concerns you?

Sorry for all the questions. I bet I'm not the only one wondering these things.

Thanks in advance for your response.

Rob

JohnPG

+1 ^

What Rob S said.

Interesting approach. But I share Rob's concerns as well.

Dan@SharkWerks

The bolt we are adding is not pulling the tube to one side, it's simply holding it from moving out of the cast pieces.

No, we are not using a nut on the inside. The tube is fairly thick (around 5mm thick) and yes it is tapped and locked with permanent Loctite.

This could cause a leak by pushing the tube IN toward the opening with the bolt and distorting the tube's shape.

The only way to properly (100% guarantee) fix and prevent this permanently is to reproduce the complete cast pieces with the inlets/outlets as part of the casting rather than connecting other pieces. Since we have not seen leaking from the motors we performed the tapped/pin fix mentioned in this thread, and I have not tested the welded fittings, I cannot answer that. The sealant in this situation is acting as an o-ring.

The welding is a bigger modification with more complexity and potential problems in the fix itself. Prior to the machined fittings being sold on Ebay ($200 as posted in these threads) we believed trying to weld the existing tubes to the cast piece was less than ideal. This kit might be a better solution; we have ordered one and do plan to see how well it works on a future build. It looks like it is not a complete kit though from the auction descriptions, we will determine this once we have seen and tested it.

To weld this will probably add 5-6 hours of labor (maybe more) to further disassemble / clean everything and weld, plus the ~$200 in parts etc. There is a greater risk involved in ruining the cast pieces and there's always the possibility the weld will crack later too.

Rovman

Was digging through older threads and found this interesting solution for the coolant hose issue that sharkwerks featured earlier in the year. I have been planning on getting the welded solution done soon but am interested what others thought about this solution in comparison to the welded solution? Better? Worse? Same?

Do any of you guys and gals out there have any experience with the threaded bolt solution to the coolant fitting issue?

Sharkwerks, perhaps you guys have some feedback on this solution. I believe you guys perform both of these repairs?

Any feedback, comments, suggestions, are welcome.

AudiOn19s

I believe the issue with this approach is that the adhesive on the fittings can still fail and leak coolant, this fix prevents a quick dump of all of the coolant though.

Credit where it's due I believe these guys were the first to step up with any sort of solution.

If this could be done with the motor in the car I think a lot more would be going this route.