For more information, please visit our website at www.gmb. This article was sponsored by GMB North America, Inc. A blown head gasket can be diagnosed with a compression test. In some situations, coolant is forced into the oil, and ends up in the oil pan. This is due to coolant getting out of its hole, past the head gasket, and into the valley. If an aluminum head warps, this is what youll find most often. Ive seen plenty which have had coolant leaks into the oil, though. It can also cause the coolant to leak into the combustion chamber and burn. I cannot specifically point out a vehicle which Ive worked on which has had oil in the coolant due to a blown head gasket. Coolant can easily leak into the transmission fluid and severely damage the transmission.Ī blown head gasket may cause the oil to leak into the cooling system. This is a “two way” leak, so the technician needs to check the transmission for coolant too. If this happens, the transmission fluid can get mixed into the coolant. The wall separating the transmission cooler from the radiator can develop cracks. Sometimes the transmission cooler is integrated into the radiator. In most trucks with an automatic transmission, the transmission fluid is cooled by a transmission cooler. Oil is under much higher pressure than coolant, so this is usually a “one way” leak.

When the oil cooler fails, oil forces its way into the cooling system. Most modern heavy duty trucks have an oil cooler. The best way to pinpoint the problem is to examine the three different parts that often cause oil/coolant contamination. Another symptom is that the oil level is higher than it should be. Look for sludge on the dipstick or underside of the fill cap (if the fill cap is on a valve cover). If there is a pinkish brownish sludge, coolant has entered the transmission.Ĭoolant in the Oil – If coolant enters the engine oil, the there are several visible signs. Also look for a pinkish brownish sludge at the top of the radiator.Ĭoolant in the Transmission Fluid – The coolant on the transmission dipstick should be pink. Transmission Fluid in the Coolant – Often, the first symptom of transmission fluid in the coolant is a swollen radiator cap seal. If the problem is more advanced, a brownish sludge will be visible at the top of the radiator. This will be visible after pulling the radiator cap, or you may see it in the overflow reservoir. Oil in the Coolant – The first symptom of oil in the coolant is an oily sheen on top of the coolant. You need to train them to look for the following symptoms:

Further, the study on filter plugging showed that in the majority of these cases moisture or coolant. Don’t assume that they know what to look for. usually a symptom of an engine or oil problem. Often, junior technicians are responsible for routine maintenance. They should also be looking for signs of coolant in the engine oil or transmission fluid. Your employees should be inspecting your trucks on a regular schedule for signs of oil in the coolant. If repairs are made quickly, major damage can be prevented. If there is oil in a heavy duty truck’s coolant, it always means there’s a serious underlying problem.

Coolant in oil symptoms