I have a 2005 Ocatavia with a 2.0fsi engine. It has quite suddenly started loosing coolant quickly, almost a whole expansion tanks worth in ~1hr of driving. The leak only occurs while the engine is running.

 

There is coolant dripping off the oil filter housing, and its very hard to see well above the oil filter to see where it is coming from. Anyone had this before? Could it be coming from the oil cooler or the oil filter holder?

 

Cheers

I've had oil cooler coolant lines and rigid piping fail and develop leaks before in other vag tsi cars. 

16 hours ago, TheClient said:

I've had oil cooler coolant lines and rigid piping fail and develop leaks before in other vag tsi cars. 

Thanks, there seems to be only one coolant line coming from the oil cooler (looking at a diagram), so that should be quick to check. Do you know if it also gets coolant from the engine block?

If it only has one coolant line, then there will be three ports on the engine block side. One for coolant. Flow and return for oil.

 

So the fault could be the block gasket side or the coolant line. If you strip some covers, trim under guard and use a light source while engine running you maybe able to see which is at fault.

 

Or, alternatively, the cooler itself is perforated somewhere like a crack in the coolant pipe weld or moulding. That is often hard to see. 

Edited 29 April, 20206 yr by TheClient

Looking more fully at these diagrams - the oil cooler is mounted to the filter housing and the housing to the block. Both have seals in between.

 

https://skoda.7zap.com/en/cz/octavia/oct/2005-419/1/115-115060/#1

 

The leak was a crack in the top of the oil filter housing. Replaced the housing and all good now.