Only cold air and coolant leak.
 

Hi.

My S8 started out loosing some coolant 2 months ago and i could see that the reservoir tank was leaking, so got a new + cap from the dealer and hoped everything would be perfect. So it was for 2-3 weeks until the annoying coolant level indicator came on once again... i refilled and 1 weeks later same **** again. Of course i found several pages on the oil cooler plastic pipe leak so had the car at a friends lift and removed the plastic cover, let the car run for ages but no sign of any leak. From earlier experience there is usually no problem finding G40 leaks since it leaves a light pink color when dried.. The engine looks like brand new and dry as dessert sand underneath..

Today when going home from work i turned the heat up a bit but only cold air came out and the coolant "alarm" came on again... Engine temp is fine and coolant level is just below minimum..

car is also dry inside..

I can also mention that from time to time when the car is started when still close to operation temperature the lower part of the front screen becomes covered with dew/fog or what you call it. This never happens if engine is cold.


Any suggestions? could all be because that plastic pipe or are the A8/S8 also having trouble with the "radiator" inside the car?

All feedback will be very appreciated :)

Going into the cylinders....
(and out the exhaust) :eek:

Hehe nope.. there is no sign of that kinda failure :)

I do see a puddle under the car(mid engine) when parked.

I'm wondering if the cooling system only leaks after the engine is shut off?
Will the pressure in the system be higher when engine is off and system is cooling down?

Puddle is probably just from the aircon drain, just clean water.
Collect some and look at it, smell it (if you dare taste it?)

If I could offer a suggestion, It might be worth a check on the main radiator. My 2.8 very slowly used a small amount of coolant for quite a while requiring a small top up every few months, no obvious signs of leaks or unwanted puddles anywhere, then when we had the only really hot day last year after I parked it after a 20 mile drive and it began to cool, coolant began a steady drip from the OSF. The rad despite looking perfect from all the areas I could physically see it had begun to corrode in the bottom corners and finally gave up the ghost. New rad cured the blighter but the leak wasn't visible at all up to the point it popped its clogs! The radiator sits against a sponge strip (presumably to stop it rattling?) that was absolutely soaked, it seemed to be holding the leaked coolant and then letting it dry out in use effectively hiding the small leak it had. Might be worth a check?? Hope you find where its escaping from!

Could be leaking where coolant pipes behind engine go into heads or hoses join the pipes.
If it was heater matrix or hoses near it leaking you would feel the sweetish smell of coolant in the car.