996TT Strange Coolant Leak

[James Guy]

Guys - I've got a coolant leak that I was looking for some advice on.

I picked up my 996TT two weeks ago from a private seller, and having hunted around many cars, I was very happy with my purchase.

This weekend I did some simple routine maintenance on the car.

I had noticed that the Coolant in the expansion tank was about 2cm below the min line, so topped up with Porsche Coolant. Took the car our for a drive, and then put in the garage.

It has been sat out there for the last 3 nights and thought I would take it for a drive - on pulling it out of the garage I noticed an egg cups worth of coolant on the floor.

Under the car I can see that there is a slow leak coming down the passenger side of the engine just back from level of the rear sway bar.

What is interesting is that the coolant has leaked back down to it's previous level, and has seemed to have stoped leaking.

Looking at the service papers, the expansion tank was replaced just 10 months ago, and I am not seeing signs that it is this again,

I am aware that this could be one of the pipes that runs the coolant from one side of the engine to the other, but wondered if anyone could help out with any advice.

I'll get the car up on stands this weekend and have a proper look.

Thanks guys

[JFP in PA]

I think you need to do some background searching on coolant leak issues with the 996 turbo cars, they have a myriad of glued in metal hose connections that tend to come loose and leak, sometimes catastrophically. There are shops that sell kits to pin or even weld in the hose ends, but all of these require pulling the engine to do so.

[richardcarrera911]

Coolant pipes run under car from front to rear, aluminum tube to rubber sometimes leak at connections mid way, I also had to replace all 3 radiators in mine which had a mild leak, and replaced all the lines under the car which are hidden under the underside protectors my car is a 2003. Worth checking whole system you have to remove front bumper to get to radiators, Pelican Auto Parts has replacements at reasonable prices and also lines.

Also check transmission mounts for cracking rubber and engine mounts whilst car is up on ramps. FYI

[Dus10R]

Coolant connectors is very common but they usually fail catastrophicaly not slowly. In fact I was approached by the NTSA regarding the issue, I think they are considering a forced reall on Porsche because it is so common. There are 7 or 8 connectors if I remember correctly. My '03 Turbo X50 had a random coolant leak for two years. Somtimes it would leak, and most times it wouldn't. Had it in the shop a few times and they couldn't find it until I had the motor dropped for modification. When they removed the air intake runners they found it, there was some kind of pipe or hose on the top of the motor near the front that had a bad gasket. Porsche's teething problems with water cooling.

[Hilux2400]

I have a 2003 Carrera C2 and have had intermittent coolant leaks. I take the view that this is a continuing problem with these cars as they have more connections, some three way, than the average domestic central heating system.

I check the coolant level frequently when the car is cold and with the car always in the same location in the car port.

One of the best options is to pressurise the system. There are quite a few kits on the market. Look out for one that is compatible with VW cars from around 1998/1990 as they have the same size coolant reservoir cap. Pump the system up to about 1 bar (15psi) and watch the pressure. Don't be concerned if it loses pressure immediately as that's due to the coolant being forced into odd air pockets. The pressure will probably set after a few minutes and then should hold for at least 2/3 minutes if the system is OK.

My last coolant leak was on the allow vent return pipe from the rads to the reservoir. This pipe is about 4ft in length with about 12 bends. The pipe had been rubbing on the bodywork.

Best of luck.

H

[James Guy]

Thanks to all for your help with this.

I spent some time this weekend trying to find where the leak was coming from. Having topped up the expansion tank, and pressurised the system, I couldn't get the car to leak again. Drove it hard, and tried all I could but no luck.

Put the car away, and nothing for 3 days, and then I checked today and its leaked again from the same place.

Short of an engine drop, I don't think there is much I can do. However, it seems intermitent, so I will take Dus10R approach for now and accept it until I need the engine dropped for another reason. Just seems very strange, and I am wondering if the most likely option is either a bad gasket, or a slight rub on the hose which settles under pressure.

[JG 996T]

I have a similar issue - intermittent leakage. Very small amounts. Can not view source, although the drips appear next to the inside of the rear wheels. Leaks appear after non-use. There is a thread or two on rennlist noting similar issue, and some have found that it was a loose/old hose connection.

The NHSTA coolant pipe inquiry relates to sudden and complete failures that are no preceded by minor leakage.

Edited June 1, 2013 by JG 996T

[James Guy]

After catasphroic coolant failure on Monday - requiring a flat bed to get me home, I had the airbox, inlet manifold and alternator off, to find this!

Apparently this is very unusual for a UK car, particulary one that hasn't been driven too hard, or tracked.

Weighing up my options -

1. Do I have an engine drop, and weld the part in - costly!

2. Use a strong suitable epoxy i.e. http://www.loctite.co.uk/loctite-4087.htm?countryCode=uke&BU=industrial&parentredDotUID=productfinder&redDotUID=1000000J0961

Frustrating - but at least I've found it Also strange that there was a minor leakage before hand!

[JFP in PA]

After catasphroic coolant failure on Monday - requiring a flat bed to get me home, I had the airbox, inlet manifold and alternator off, to find this!

Apparently this is very unusual for a UK car, particulary one that hasn't been driven too hard, or tracked.

Weighing up my options -

1. Do I have an engine drop, and weld the part in - costly!

2. Use a strong suitable epoxy i.e. http://www.loctite.co.uk/loctite-4087.htm?countryCode=uke&BU=industrial&parentredDotUID=productfinder&redDotUID=1000000J0961

Frustrating - but at least I've found it Also strange that there was a minor leakage before hand!

You have the fairly well known problem of the cooling hose fittings coming loose from their mating parts. There are companies that offer solutions ranging from pinning your existing fittings, to welded units that replace them. Either solution requires dropping the engine to get at all the fittings in the car. Kits range from do it your self welding of new connectors:

DIY pin systems using bolts:

Threaded hose end replacements:

A lot of tracks now require one of these fixes before a Turbo or GT car is allow to run.

[James Guy]

Thanks JFP - totally understand that the ideal option will be to weld all the connectors. I plan to have this done as soon as I drop the engine.

The car isn't actually tracked, nor do I have plans to do so. Having only purchased the car 2 months ago, I've been pretty unlucky!

Has anyone secured with epoxy for a second time? Not perfect I know, but is this an option?

[JFP in PA]

Thanks JFP - totally understand that the ideal option will be to weld all the connectors. I plan to have this done as soon as I drop the engine.The car isn't actually tracked, nor do I have plans to do so. Having only purchased the car 2 months ago, I've been pretty unlucky!Has anyone secured with epoxy for a second time? Not perfect I know, but is this an option?

Considering what happened the first time, most people either go for the pinned (which is also glued) or welded approaches as they both assure the parts will not move as they are mechanically locked in place. Some also remain concerned that even with the pins, eventually the glue line will fail again and you will still have leaks. Going welded or threaded eliminates any possibility of that happening. As you are going to need to drop the engine in any case, may as well do it right and do it once.........

[James Guy]

Thanks JFP - totally understand that the ideal option will be to weld all the connectors. I plan to have this done as soon as I drop the engine.The car isn't actually tracked, nor do I have plans to do so. Having only purchased the car 2 months ago, I've been pretty unlucky!Has anyone secured with epoxy for a second time? Not perfect I know, but is this an option?

Considering what happened the first time, most people either go for the pinned (which is also glued) or welded approaches as they both assure the parts will not move as they are mechanically locked in place. Some also remain concerned that even with the pins, eventually the glue line will fail again and you will still have leaks. Going welded or threaded eliminates any possibility of that happening. As you are going to need to drop the engine in any case, may as well do it right and do it once.........

Thanks JFP. Wasn't planning on an engine drop until next year when I have other work done.. Will fix short term then have them all welded with engine drop.

[Silver_TT]

To give you an idea of what this should cost, I was quoted $1900 USD for this job by a local indy (who does good work for good prices). If the engine is already out for another reason, obviously it would cost a lot less. The only other thing I would add is I would ask who is doing the welding and talk to them. You definitely want someone who is good and experienced with this type of welding if you go ahead with the job. JFP is absolutely right about everything he is saying but if you're trying to bide your time, I would try to just re-glue it with the Porsche specified epoxy (assuming you're not tracking the car).

[porsche996tt_tpe]

yep, nothing short of catastrophic... happened to me last week on a freeway. spent like a hundred or two to have it fixed (welded). i heard there was 3 pipes. i only fixed the one that broke, which is the easier one to fix; the other two require further tripping of the engine, I was told. can't believe this happens to a supposedly 'reliable' car...

[Silver_TT]

yep, nothing short of catastrophic... happened to me last week on a freeway. spent like a hundred or two to have it fixed (welded). i heard there was 3 pipes. i only fixed the one that broke, which is the easier one to fix; the other two require further tripping of the engine, I was told. can't believe this happens to a supposedly 'reliable' car...

There are more than 3 pipes -- there are 3 for the water pump housing alone.... Should be more like 8 pipes. See this thread by jpflip, which is a very good reference on this topic (including all parts with part #s):

http://www.6speedonline.com/forums/996-turbo-gt2/267584-coolant-pipe-repair-parts-needed.html

Edited August 16, 2013 by Silver_TT

[JFP in PA]

yep, nothing short of catastrophic... happened to me last week on a freeway. spent like a hundred or two to have it fixed (welded). i heard there was 3 pipes. i only fixed the one that broke, which is the easier one to fix; the other two require further tripping of the engine, I was told. can't believe this happens to a supposedly 'reliable' car...

There's more than 3 pipes -- there are 3 for the water pump housing alone.... Should be more like 8 pipes. See this thread by jpflip, which is a very good reference on this topic (including all parts with part #s):

http://www.6speedonline.com/forums/996-turbo-gt2/267584-coolant-pipe-repair-parts-needed.html

Silver_TT is correct, there are eight in total.

[Silver_TT]

yep, nothing short of catastrophic... happened to me last week on a freeway. spent like a hundred or two to have it fixed (welded). i heard there was 3 pipes. i only fixed the one that broke, which is the easier one to fix; the other two require further tripping of the engine, I was told. can't believe this happens to a supposedly 'reliable' car...

Notwithstanding this issue, the 996TT is still incredibly reliable. Porsche was not alone in similar issues when moving to water cooled technology.

[JFP in PA]

The Metzger lump is by far one of the best designs they produced, both powerful and durable. The glued in water connections is just one of those "bad ideas" that all OEM's are prone to on occasion when trying to keep costs down.