The Mitsubishi Pajero Owners Club®

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Preventing Head Gasket Failures

Head gasket failures on the 3.0L Mitsubishi have always been an issue. Most head gasket failures typically happen on engines that have had recent cylinder head service or have been remanufactured. Causes for these failures can be related to a number of things.
Always clean or replace the EGR valve using a new gasket. EGR valves that have bad carbon build up can cause a restriction of the flow of exhaust gases or, if it’s not working properly or is leaking, it can change the combustion process. The center two cylinders are usually the ones affected with burning or cracking of the combustion grommet, which then would cause exhaust gases to enter the cooling system, potentially causing overheating.
Always be sure to replace or check the cooling system on the vehicle. Older cooling systems on these vehicles are another cause of possible head gasket failure. These older systems do not flow well and do not allow for the adequate heat transfer to cool the engine. This inability to transfer heat from the coolant can cause increased operating temperatures and potential head gasket failures.
Always use the correct torque specs. Some early service manuals show head bolt torque specs to be 65-72 ft. lbs. Later on the engine manufacturer changed the spec to 80 ft.-lbs. Since the specs differ based on the VIN code and the year, be sure to reference an up-to-date torque spec guide.
Use a quality head gasket. Because of the cast iron block and aluminum cylinder heads the amount of thermal motion on this engine is high. This motion can destroy some head gaskets of a lesser design.

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