Generic coolant or pure water??

[Rob R]

The coolant on my 997 C2S (2005) seems low.

Can generic (Mobil) be used or am I better to use pure water until I can get it looked at on Monday? The Mobil detail does not say it CAN'T be used but I have read on forums that Porsche has something specific..??

www.mobil.co.uk/UK-English-LCW/carengineoils_car-c...

Any help much appreciated please.

[Pope]

The original coolant from Porsche is lifetime fill - it can remain in the system indefinitely - assuming it doesn't get contaminated during its service life. The ratio is 50:50 mixed with pure water to achieve a protection of -37C.

Bear in mind the car holds approx 28 litres in the system; adding a few litres of water over the service life of the original fill wont lower the protection by much.

[Rob R]

thanks very much Pope.

Does the water need to be distilled water or is tap water okay?

[Pope]

Tap will do fine; once you fill it give it a run, note the level once the engine is up to temperature - the system pressurises (approx 1 bar over atmospheric) and as such the level appears to drop.

Two things that you should be aware of:

MAKE SURE THE CAP IS SCREWED ON STRAIGHT - IT'S EASY TO CROSS-THREAD (it will spew out coolant when up to temp and ruin you week)

DO NOT ATTEMPT TO REMOVE THE CAP IF THE ENGINE IS HOT (a Mount Vesuvious reenactment on the driveway won't be fun)

Monitor the level after the initial run - after the first drop it shouldn't change dramatically - the system is closed so a dropping pressurised level indicates a loss somewhere.