Service VME - 4.6L, L37, LD8 Engine Exhaust Leak

When servicing the vehicle with the VIN you entered, the following diagnosis might be helpful if the vehicle exhibits the described symptoms.

This service VME concerns late built 2002 Devilles, Sevilles and Eldoradoes that may have an exhaust leak on the front bank. The exhaust leak is occuring between the manifold and the head because the gasket has moved out of position during assembly. The leak is usually out of the top edge of the gasket. The exhaust manifold may appear warped because part of the gasket is exposed, but the exhaust manifold is not damaged and does not need to be replaced.

Some late built 02 engines have a new boss on the front cylinder head that will be used in the 03 model year. This boss interferes with a tab on the top edge of the exhaust manifold gasket, the tab closer to the front of the engine. Sometimes during installation this tab will force the exhaust manifold gasket out of position.

A revised gasket is being released for service to correct for this concern. Until this new gasket is available a new existing one, part number 12557769, can be modified to provide clearance.

To modify the current exhaust gasket install the tab located on the top edge of the gasket, towards the front of the engine, in a vise. Then bend the gasket outboard till it makes a 45 degree angle from the back surface of the exhaust gasket. This should eliminated the interference with the boss.

This is Ron Caponey, brand quality manager for Premium engines.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. This diagnostic approach was developed for the vehicle with the VIN you entered and should not be automatically be used for other vehicles with similar symptoms.