Losing Coolant

[glenndeweirdt]

I have a frustrating problem with my '99 996 tiptronic with 46k miles. I am the second owner and purchased the car four years ago with 12k miles. The car is my daily driver with zero track time.

About 18 months ago I noticed the low coolant light was on. Replaced about 1 qt. of coolant (Porsche coolant). About 6 weeks later I added about 1 pt. of coolant to top off. I checked all hoses and clamps-nothing. No wax or brownish tinge to the engine oil. No coolant on ground. Took the vehicle to local independent who did pressure test, checked oil for contamination, checked all seals and hoses-negative.

I continued to add about a pint of coolant every thirty days for the next six months or so. Finally took it to dealer August '07. Dealer pressure tested, checked oil, and replaced coolant resevoir ($900). No leaks until January '08.
Began the monthly ritual of topping off coolant resevoir with a pint of coolant. No oil contamination, no leaks, no puddles!!

I had an unrelated starting problem this past week ($1500 for a new key but that is another long story). Brought car to another independent and had them check the cooling system since the car was there-nothing! Car had to be flat-bedded to dealer for new key. Discussed problem with dealer. They performed complete cooling system check -nothing!!!!

Do I have gremilins? Is this a portent of dreaded intermediate shaft failure or porous casting? Once again, two independents and the dealer have determined no oil contamination.

I don't have a big problem with adding coolant if I know there is not a serious problem. What do you guys think??

Glenn

[LanceGT4]

check the radiator inlets for trash, the 99 Carrera 4 i just aquired has a history of the same compliants in the service records.
the radiators on both sides was about 20% covered in leaves and trash off the roads.
cleaning brought the temp down on a normal day about 5 - 10 degrees
I'll know more next week when the forecast is for hot weather again.
I can't believe I made the 200 mile trip home in 107 degree weather without going over 200.

[glenndeweirdt]

Lance, Unfortunately your advise is a little late.
Final update on my ill-fated 996. On a sub zero afternoon this January I started my 996 after it was cold soaking in my parking lot all day. The post-startup cacophony from the engine compartment ( a combination of metallic grinding, moans, and hissing) was distressing to the point of near fecal contamination of my skivvies. It was determined on examination at my local forensic mechanic that my P-car had suffered the dreaded cracked cylinder sleave syndrome. Replacement of the engine is the only remedy known to mankind for this unfortunate malady. I found it unwise to spend $17K for a Porsche crate engine with install on a car with a market value hovering in the low 20's. My daily driver is now an '05 Maxima but I am currently looking at a CPO '07 BMW 330Xi sedan (don't tell my wife).

On the positive side I got almost $23K for my '83 911SC and was able to turn that into an '03 Boxster with 22K miles and Porsche Certification from Napleton Porsche. I love the Boxster-and I am not gay!

[LanceGT4]

Sorry to hear about your engine. i don't even want to imagine what the sounds were like:-(
Good luck getting the BMW past your wife.

I've put another 1200 miles on the car since i cleaned the intakes and the water level seems to be stable. I think the level changes i see are from how long its rested when I checked. These engines seem to take a long time to cool.

[glenndeweirdt]

Thanks for the sympathy.