Oil in Coolant Symptoms, Causes, and Remedies

Engine Oil in Coolant Reservoir - Can the Engine Oil Cooler Leak Into the Coolant? ; EUROW. 446 posts · Joined 2022 · #2 ; mschwab327. 169 posts ... I was on a trip, over 300 miles from home, when my 2014 Passat TDI started spewing black engine oil out of the coolant overflow tube. One tip, is to double check the oil cooler itself for trueness against a straight edge just to be sure that it is not slightly warped. Not ... I have asked an "Audi specialist" garage for an opinion on the oil in the expansion/coolant tank. They believe the oil cooler to be the most likely fault. Also, if it is mixing coolant and oil stop driving it till you make sure there's no coolant in the oil. Watered down oil is how spun ... Check your transmission dipstick for possible coolant contamination, also. That "film of oil" in your coolant overflow tank may not be that much ... The coolant in a 5.3L Vortec does not communicate in any way with the intake manifold so a blown intake manifold gasket can not get oil into the coolant. A leak between the oil containing part of the block and the cooling part is the only way that you can get motor oil in the coolant. The oil dipstick looks nice and clear/dark pure oil, no coolant. Could it be related to the radiator, or any other part of the car that would have been damaged ... If you have oil mixed with coolant in the reservoir, you will notice a thick, milky or gravy-like substance that is a tell-tale sign that you have this issue.