Causes of engine overheating

I get a lot of questions as to why the engine is running hot - way above the normal range on the temperature gauge. Here are a few things to check out.

First, make sure it IS really running hot. It may be a failed temperature sending unit. Check the coolant temperature with an accurate temperature measuring device.

If it really is running hot check the thermostat. Remove it and put it in a pot of water on the stove. Heat the water while monitoring the temperature. The thermostat should open at the temperature stamped on it, normally 190 degrees F.

Next, are you losing coolant at all? I mean an internal leak as in blown head gasket. Have the coolant tested to see if there are combustion by-products in it which would indicate that combustion gasses are getting past the head gasket.

Next, check the cooling fins on the radiator to ensure that they are firmly attached to the cooling tubes. Salt from the highway will corrode the solder and break the bond between the fins and tubes thus preventing sufficient heat transfer from the coolant to the atmosphere.

Do you have electric fans? Are they turning on while idling in traffic? If not then find the problem and resolve it.

Of course if you are losing coolant from a leaking radiator or hose or possibly from the heater core, fix it!!

Message me at BobHewitt@Misterfixit.com

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