Examine the transmission fluid level for signs of cross-contamination if the cooler is the source. Another likely suspect is the transmission cooler located inside the radiator; if the internal radiator tubes rupture, pressurized transmission fluid can leak directly into the coolant, creating a similar oily appearance.
How to Check the Oil Coolant Mixture for Contamination
The water pump circulates a mixture of coolant and water through the engine block and cylinder heads, absorbing heat and carrying it to the radiator. If the transmission cooler is leaking, the radiator will need to be replaced.
When these seals fail due to age, overheating, or improper installation, pressurized combustion gases or oil can be forced into the coolant passages. This mixture of coolant and oil does not happen by design and signifies a breach between the passages that should keep these fluids entirely separate.
How to Check the Oil Coolant Mixture for Contamination
While the repair costs—ranging from a few hundred dollars for a gasket to over a thousand for a radiator replacement—may seem significant, they are trivial compared to the cost of rebuilding or replacing an engine destroyed by overheating. This lack of lubrication leads to rapid scoring of the cylinder walls and bearings, which can result in warped heads, seized engines, or complete mechanical failure.
More About Oil in the coolant reservoir
Looking at Oil in the coolant reservoir from another angle can help expand the discussion and give readers a second clear paragraph under the same section.
More perspective on Oil in the coolant reservoir can make the topic easier to follow by connecting earlier points with a few simple takeaways.
