The Anatomy of Healthy Cars: A Service and Repair Blog

What Happens When an Engine Oil Cooler Begins to Fail

by Brittany Marshall

Many cars today are fitted with an engine oil cooling system, especially those designed for towing. The cooler is meant to keep the lubricant in tiptop condition and ensure that it always provides maximum protection for those crucial components. Yet as with anything else mechanical, the oil cooler can develop problems and these can manifest in a number of different ways. While you should always take the vehicle in for regular servicing so that technicians can check these parts, what do you need to be on the lookout for in the meantime?

How Things Work

A typical oil cooling system is similar in many respects to a conventional air conditioning setup. Oil is diverted through to this cooler, where engine coolant flows around thin tubes. The heat from the oil is pulled out through those tubes before the coolant is sent through the vehicle's main radiator. In this case, therefore, the main coolant is responsible for regulating the temperature of both the engine block and the lubricating oil.

Within the oil cooler, engine oil and lubricant pass next to each other in close proximity. Sometimes, however, one type of liquid can leak and merge with the other, causing potential problems down the line.

Oil in the Water

For example, engine oil may leak out through some vulnerable seals within the adaptor mechanism. This can happen when the engine is under heavy load, and the oil pressure is much greater than the coolant. This may cause lower oil levels within the engine and, eventually, damage.

Water in the Oil

Conversely, coolant may be forced into the oil system through the adapter when the engine is off. The coolant pressure may be higher than the oil pressure, which can cause the engine sump to fill up with coolant instead. Of course, this will compromise the efficiency of the oil — with potentially disastrous consequences.

Pressure Points

Both engine and radiator connect to the oil cooler via the adapter. Individual lines trace back and forth between these components, protected at various points by gaskets or O-rings. Unfortunately, these smaller parts can deteriorate with time and may eventually perish.

Observation and Repair

You should ensure that your mechanic takes a good look at the condition of your oil cooler during any regularly scheduled service. If there is any hint of internal contamination, make sure that the oil cooler is replaced before any major damage is caused. 

Contact a car repair technician to learn more.