How to clean engine oil from cooling system

How to clean engine oil from cooling system

Learn how to clean engine oil from cooling system.

Professional Installers offer the following information on cleaning engine oil from a cooling system in internal combustion engines.

Occasionally, engine oil and cooling system liquids are allowed to mix while an engine is running. In certain situations, cleaning the oil from the system without removing all cooling system components may be successful. 

contaminated engine oil
contaminated engine oil
clean engine coolant
clean engine coolant

The method described below is effective and should be implemented after the defective component has been repaired or replaced.


1. Prepare a mixture of dishwasher detergent and hot water. Use a rate of two ounces (dry measurement) of detergent to one gallon of clean water. Make sure to mix enough solution to be able to fill the entire cooling system.

2. Fill the cooling system from the highest point possible and allow for an air bleed to maximize the fill effort.


3. Start and run the engine for a period of five minutes and then stop the engine and drain the entire cooling system. Repeat this procedure with fresh solution until all traces of oil have been removed.

4. After all traces of oil have been removed, fill the entire system again with clean water and start and run engine for another five minute period.

5. Stop the engine and allow ample time for the water to drain completely from the entire cooling system.

6. Fill the cooling system with a 50/50 of antifreeze and clean water making certain to use only antifreeze recommended by that particular engine manufacturer.

Failure to use the appropriate antifreeze or coolant may result in engine component deterioration and result in premature engine failure. Mixing incompatible coolants may also provide undesirable cooling system effectiveness and result in failures.

Now you can see how important it is to learn how to clean engine oil from cooling system.


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