How to Fix Overheating on a Northstar

by Baptist Johnson
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The Northstar engine series is a family of automobile engines designed by General Motors. The Northstar has been used in several cars in the GM lineup, including the Cadillac Seville, Buick Lucerne, Pontiac Bonneville and Cadillac Eldorado. Like all engines, the Northstar requires proper maintenance to stay in good condition. An overheating engine is a definite indication that something is wrong. Run through a check list of common overheating problems to troubleshoot the source of your engine problem.

Step 1

Check your coolant level. One of the most common causes of an overheating engine is a coolant leak. Start by checking to see how much coolant is in your system. Ignite your engine and let it idle for at least 10 minutes. Look on the ground underneath your engine and inspect for a coolant leak. You should be able to identify coolant as a yellow, blue or green liquid.

Step 2

Check your thermostat. The thermostat gauges the temperature of the engine to control the flow of coolant into the cylinder block and radiator. A faulty thermostat might not open, meaning coolant won't flow. This in turn will cause the engine to overheat. Check the thermostat by starting your engine and letting it idle for a few minutes. After 10 minutes of allowing your engine to idle, touch the upper radiator hose. The radiator hose should be hot, which indicates your thermostat is fine. If the radiator hose is not hot, the thermostat might need to be replaced. Locate the thermostat housing inside the coolant container.

Step 3

Check for a leaky head gasket in your engine. A leaky head gasket is difficult to diagnose because you won't find an external leak. Instead, it leaks coolant directly into the engine's cylinders or crankcase. One symptom of a leaky head gasket is a rapid loss of coolant with no visible coolant leak underneath the vehicle. If you notice white steam coming out of the exhaust, you can be sure you have a leak in your head gasket. A leaky head gasket can be sealed temporary using a sealant. However, you should get the gasket fixed as soon as possible. Take your vehicle to a professional mechanic for assistance.

Step 4

Inspect the fan blade and radiator fins. The fan blade is located just in front of the radiator and should be attached to the fan belt. Make sure the fan blade spins when you ignite the engine.

Step 5

Check the water pump system. The water pump helps circulate coolant from the radiator to the engine. The water pump is located on the front of the engine. Inspect the water pump closely. Make sure the impeller on the water pump spins. If the impellers do not spin, it might be an indication that there is little or no coolant circulation.

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