I hear tremendous things about this forum and the technical competencies of the members, so I hope you can help.

I just bought a 2003 996tt with 70k km. I got a low coolant light. went to dealership and they said they did a simple 20min pressure test and couldnt find a leak and added 1 liter of coolant.

there appears to be no history of coolant issues.
They told me to monitor it and i asked if would do a full pressure test (apparently up to 2hrs) another day. they said they would.

the car is still under warranty, so i assume they will not charge me for the full pressure test, if they dont find any leaks. or will they?
how common is it to lose that much coolant for a car this old?
what can this likely be? (coolant expansion tank?)
ive notice mainly blue (and not sure if white smoke) on start up on occassion. but i hear this is somewhat common.

 

You shouldn't be losing coolant.

I had a coolant leak when I bought my car, so I did ask questions and carried out a few searches. One weak point in the system is the cap on the expansion tank. Take it off and have a good look around the threaded section to see if there is a white crust. It's not an expensive part anyway so if you continue to lose coolant it's a cheap thing to try - just to rule things out.

Radiators are a common problem, because they are quite exposed. But a pressure check should have shown up any leak there.

My leak turned out to be a leaking connector in the engine bay, but it took several trips back to the dealer to find it.

 

What color is your cap on the coolant tank? If it is blue, then it needs to be updated with the black cap. They are a known issue, and most likely the cause.

 

When I replaced mine (about 4 or 5 months ago) the replacement cap was also blue?

ETA : This thread reminded me that the last time I checked my coolant I thought it had dropped slightly. Just checked it again, and it appears I definitely do have a leak still. Not the original one (which was much faster) - but it's clearly dropped well below the min line (from max) in the last 4-5k miles or so.

 

It is not normal behavior for a properly functioning and intact cooling system to lose any coolant.

Absent any fluid under car or strong smell of anti-freeze chances are good the "leak" is a bad cap. Replace it. You want a cap ending in part number 03 or 04. I can't speak to its color. Just go to the Porsche dealer parts counter and have parts department look up part # based your Turbo's VIN.

Add distilled water until level ok then install new cap and check coolant level every once in a while. If it drops again, there's a leak.

You'll have to ask the dealer if it performs a test to try to find the source of a symptom you report -- low coolant -- and finds no leak or no reason for the low coolant level if it will charge you the diagnostics time.

Sincerely,

Macster.

 

OK - my replacement (blue) cap ends with 04 (my original cap ends 01).

 

mine is a blue cap ending with 01.
i couldnt take it off by hand to see threads. is it that hard to remove?
i do notice some white residue in the overflow, but it seems too minor.
so i need to ask for black cap with 04?

 

My leak was also at the cap. The replacement I got 2 years ago ends in .02 and is blue.
I havent had to add any water since changing the cap. I havent driven the car in 4 day and when I just opened it the system is still under pressure.

 

It can be - mine takes quite a lot of effort to get off sometimes (and I did manage to crush my thumb the first time it suddenly turned!).

 

the coolant level has remained the same since topped up last week.
might very well be the older cap.