I have an issue with my 97 1.8T Quattro using coolant. I've checked for external leaks and can't find any. The engine oil is still clean.

Has anybody had this issue before?

Is it possible for it to be leaving through the head gasket and out the exhaust?

  • 1
    How fast are you losing the coolant fluid? What color is your exhaust smoke?
    – chilljeet
    Apr 29, 2015 at 5:28
  • 2
    check the plastic pipe/flange at the back of the engine (the one with the coolant temp sensor). they tend to have a slow leak that drips onto the exhaust, which burns off the coolant before it hits the ground
    – user4546
    Apr 29, 2015 at 17:37

2 Answers 2


Engine coolant can leave the cooling system by different ways:

  1. Through a damaged hose.

  2. Through a damaged radiator or reservoir.

  3. Through a damaged head or head gasket. In this case, white smoke (which is just steam) is coming out of the exhaust.

  4. This is an Audi special: Through a damaged / worn-out coolant reservoir cap.

Audi Coolant Reservoir Cap

The cap has a sealing which gets worn-out over time. The engine coolant is under pressure while the engine is hot. If the sealing doesn't work properly, small amounts of coolant leak through. Unfortunately you can't see any stains from this. I suggest to change the cap and see if that helps.


Yes, it is possible for the coolant to leave through the exhaust, if the head is warped or the head gasket is compromised.

To check for this, you should get a compression leak-down test done.

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