Coolant Usage 2005 Turbo

[derekmines]

For the past 6 months or so my 2005 CTT with around 90k miles has been using coolant to the tune of around 2 litres every 500 miles (that is from the max mark to the warning symbol appearing)

 

i'm assuming that this is not normal, but there's no obvious leaks, no puddle on the garage floor, no mayonnaise in the oil etc etc

 

Where else should I be looking / what else could be the fix for this problem?

[mihaipopa]

Assuming the pipes have already been changed, I would first check the coolant reservoir. Mine started leaking at ~95k miles (also no smell, no visible leaks, just that dreaded check coolant level warning every other day). I pressurized the tank and sure enough there was coolant dripping slowly from the seams. Quick and relatuvely affordable replacement

[derekmines]

I don't believe that my pipes have already been changed, sadly I don't know how to confirm this for sure....

 

The leaking reservior is possible, I recently had to replace the filler neck for the washer fluid bottle as it had partially melted on the seams.

[hthighway]

I don't believe that my pipes have already been changed, sadly I don't know how to confirm this for sure....

 

Here is a link on how to tell if your pipes are metal or plastic:

http://rennlist.com/forums/porsche-cayenne-forum/550109-plastic-or-aluminum-coolant-pipes-how-to-tell-without-intake-removal.html

[mcbit500]

A friend of mine who owns my old 2005 CTT has just had the reservoir fail. Car is a 201k ams on original coolant pipes. Total cost at ARM AED 1200.00

[deilenberger]

Coolant isn't "used" - ie - consumed in a normal system. The level shouldn't change. If it drops (and 2 liters in 500 miles is a LOT) then there is a leak. With the complexity of the cooling systems on these beasts tracking down the leak is often a tedious and difficult thing.

 

If you have a friendly mechanic - putting it up on a lift and taking all the belly pans off is a good first step. Look in the pans for any signs of leaking - wetness or dried coolant (Porsche coolant dries into a white/reddish sort of hard crud.)  Then looking upward with a Maglite and going over the entire underside of the engine compartment.. look for trails of white crud, follow them upward and you're likely to find the source of the leak.

 

My persistent leak (and it was only ounces per 1,000 miles or so) finally was tracked down, after pipe replacement, after being at the dealer multiple times - to a defective casting on the rear of the engine. It was the casting that connects the two cylinder banks.. and it had a tiny crack in it where it had a blind plug (in a tapped hole that wasn't used on my P!G.)  Somehow the mechanic managed to replace it without engine removal - but this was under CPO. I'm sure if I'd been paying for it the engine would have to come out..

 

With 2 liters/500 miles the trail should be quite evident.

[derekmines]

 

With 2 liters/500 miles the trail should be quite evident.

 

Sadly it was quite evident..... the usual Cayenne plastic coolant pipes have failed on my 145,000km car

A raft of new parts will be ordered from the USA and shipped here as it's much cheaper that way.

 

Thanks to all for the advice.