996 Engine Coolant Loss

[Baps]

Someone over at 6speedonline recommend that I try posting this here :

I've owned a 996 C4 from new getting on for three years now (purchased Jan 2001) and, other than a gearbox failure just after purchasing the car and a subsequent oil leak the car has been pretty reliable.

However recently the temperature gage warning light started flashing, on investigation this was found to be as a result of the coolant level having dropped substantially (top up required 4 to 5 pints). Alarmingly over the following couple of days it proceeded to use about a pint of water a day. On checking the oil I found that it didn't look very healthy (almost brown in appearance), and there appeared to be large amounts of emulsion formed inside the oil filler cap and neck, the oil level also seemed excessively high.

This made me think that I was suffering a head/gasket problem and arranged for the vehicle to be recovered to the local Porsche centre.

The garage has subsequently stated that they can find nothing wrong with the car and are not observing any coolant loss. They also stated that the collection of emulsion at the top of the filler cap is common and due to condensation.

This means that I've either been hallucinating or a failure has occurred that Porsche or the garage don't want me to know about for whatever reason. It should be noted that the garage has had the car for in excess of a week. The car is also still under warranty.

Any clues ?

Note that the subsequent coolant level drops where observed with the engine in a cold stopped state.

Thanks in Advance,

Baps.

[Guest]

I assume that you don't have a crack in your coolant tank. I know you're not in the US, but it might be helpful to have your oil tested if only to have a report handy for any future needs.

Check out http://www.youroil.net/ I've had my oil tested there. They are very professional. The man to talk to is Larry Turner, l02turner@comcast.net

regarding the analysis.

Hope your problem gets solved. :)

[Loren]

If you are losing coolant then you have a leak. Several possibilities could be the cause. Most frequent are a cracked coolant tank, leaking tank cap, and leaking hoses. An internal failure (where coolant is in the oil) is also possible but fairly rare.

A good shop should pressure test the system (using proper testing tools) and locate the leak. For tank leaks look around the base of the tank in the engine compartment and down under the car (after a drive). Cap leaks usually leave a trace of coolant near the cap and hose leaks could be anywhere under the car from the front radiators back. Tanks, caps and hoses are all pretty easy fixes.

[Baps]

I assume that you don't have a crack in your coolant tank.  I know you're not in the US, but it might be helpful to have your oil tested if only to have a report handy for any future needs.

Check out    http://www.youroil.net/  I've had my oil tested there.  They are very professional.  The man to talk to is Larry Turner,  l02turner@comcast.net

regarding the analysis.

Hope your problem gets solved.  :)

Unfortunatley I didn't think to take a sample of the oil before passing the car to the garage, this has now been changed as the car was due for a service the week after the problem occured anyway. Hopefully there isn't anything serious wrong, I guess I'll just have to keep an eye on things when I get the car back.

Cheers,

Baps.

[Baps]

If you are losing coolant then you have a leak. Several possibilities could be the cause. Most frequent are a cracked coolant tank, leaking tank cap, and leaking hoses. An internal failure (where coolant is in the oil) is also possible but fairly rare.

A good shop should pressure test the system (using proper testing tools) and locate the leak. For tank leaks look around the base of the tank in the engine compartment and down under the car (after a drive). Cap leaks usually leave a trace of coolant near the cap and hose leaks could be anywhere under the car from the front radiators back. Tanks, caps and hoses are all pretty easy fixes.

The garage pressure tested the system and couldn't find a fault, they also road tested the car over a couple of days and couldn't reporduce a subsequent drop in level.

I note that at rennlist.org the 996 faq states,

Another possibility may be that under very hard acceleration coolant is actually temporarily sucked out of the reservoir to the point where the warning is displayed. Topping off the car and restarting may clear the light.

Interrestingly enough the first occurance (when the warning light started flashing) was after heavy acceleration, although the subsequent drops where after "normal" driving.

Hmm, I'm left scratching my head, and worrying just a little bit. Anyway I'm getting the car back today, just need to keep an eye on the level...

Thanks,

Baps.

[ninerguru]

On my late '99 C2, I was experiencing the flasing light during track events. I also had a tank leak that was dropping antifreeze on the exhaust. After replacing the tank, the light went away even while tracking the car. I think that I read somewhere that the latest tanks had a redesigned "window" for the sensor. BTW, the sensor just plugs into the tank using a bayonet lock. No coolant loss if you remove it from the tank. Lou

[Baps]

Well well well. After nearly 12 months of the local porsche center telling me that this probably wasn't an internal engine failure, oil finally started leaking into the water the other week. They're now saying (should I say, admitting) that its a cracked cylinder head.

Looking around on the WEB seems like there's a lot of 996 engine failures starting to crop up on cars with 30K+ mile on them.

Probably explains why they offered such a poor px value against it.

Hope, the soon to arrive GT3 isn't as flaky. Sigh!!

John.