giuseppesalvato

I have engine oil filling up my coolant expansion tank on a 2001 E220cdi, I have replaced oil cooler with a new seal, could a blocked crankcase breather cause enough pressure to build up and force oil into the coolant side of the oil cooler?? thanks for any help.

Ausmbtech

Its more likely to be oil coming from your transmission cooler than engine oil cooler. Depending on your exact model it may either be a seperate heat exchanger or in the radiator. Most likely it's the radiator.

Once you have solved the cause of the oil leak it will take a few flushes before you get all the oil out of the coolant.

giuseppesalvato

Thanks for your reply, my car has manual transmission, so l believe it does not have an oil cooler, must have a look at the crankcase breather today, its has done about 190K miles so far, so it might need cleaning. Soda crystal l hear might be a good method of cleaning the cooling system, and a bit of washing powder to give it a sparkle.

Ausmbtech

Seeing it's manual then you wont have a gearbox cooler.

I would flush the radiator, there are products available for cleaning oil from cooling systems, they definitely do help!

giuseppesalvato

thanks for that, will definitely look them up.