Coolant Leak

2.7T Coolant Leak


This page is devoted to addressing a problem afflicting the Audi 2.7 liter turbocharged engine – a slow coolant leak into the engine oil circuit.

QI have a coolant leak; does my car have this particular problem?

A – There are a variety of places where coolant can leak from the cooling system. One common location is the auxiliary coolant pump, that I discuss on this page. The focus of this page is one particular problem; a slow loss of coolant into the engine oil with no indication of loss, other than the slow drop in coolant level.

What follows is a suggested list based upon the experiences of people who have been through this.

  1. Check your coolant expansion tank for discoloration. This could indicate that oil is also entering the coolant system. Note: This has not been a symptom for the people who have been affected by coolant contamination of their oil.
  2. Have a thorough visual inspection performed by someone who knows where to look for coolant leaks.
  3. Have a coolant system pressure check performed.
  4. Have an engine compression test performed.


QHow do I determine if coolant is getting into the engine oil?

A – The best way to answer that question is to get an oil analysis from a sample of your engine oil. A number of 2.7T owners have used the services of Blackstone Laboratories ( It is an easy process to do when changing your oil, and if you suspect the coolant might possibly be entering your engines oil it’s a good idea to do an oil change. Here is a sample of an oil report showing high levels of sodium, the indicator that coolant is getting into the oil.

Another symptom is a low oil level light when a visual check with the dipstick shows the oil level to be adequate. This does not always happen, but has happened in some cases.

You can also disconnect the PCV valve from the Y-pipe and inspect the oil that pools there for a chocolaty color. Follow this link for more information.


QWhy is it important to get an oil analysis done?

A – Coolant in the engine oil can lead to accelerated wear of the engines components. The oil analysis will determine for certain if the coolant is getting into the oil and will show if there are elevated level of metals in the oil, which would occur if the engine components were wearing faster than expected.


QThe oil analysis confirmed coolant is mixing with the engine oil, what should I do now?

A – You now find yourself in the same situation a number of us are in.


Q My oil analysis has shown that I have more wear than expected, is there anything else I can check?

A – You could try and open up the oil filter to see if any large metal particles have been filtered out.


Q What is being done to address this issue?

A – Follow this link to find out what’s being done.

Finally, here’s some information from the 2.7T self-study guide on the coolant and oil systems.


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