Dexcool does not play well with other coolants. Flush the system. The intake manifold gaskets are known for failing due to the way the new engine design clamps the gaskets. Personally I would start by flushing the system, if you can find some the old Dawn machine dish detergent (not the hand wash stuff) it really does a number on the grease oil and deposits in the system. Or you can go with Prestone cleaner. Rinse it well then fill with water and see if the oil returns. If it does you should be able to tell for sure which it is. Then form a plan. If you are seeing leaks you will need intake gaskets anyway. So plan on intake gaskets, thermostat, replace the hoses and new coolant (go with DEXcool), possibly a water pump as well.
If the oil does return, and it is transmission fluid, add a radiator. If it returns and it is engine oil you will want to think a bit.
Saturday, April 29th, 2017 AT 4:09 PM