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Low Coolant Indicator Or Coolant Leaking From Engine - keywords crossover gasket head

Subject:Low Coolant Indicator or Coolant Leaking from Engine

Models:2006 Chevrolet Impala, Monte Carlo,
Equipped with 3.5L (LZ4/LZE) or 3.9L (LZ9) engines
2006 Chevrolet Uplander
2006 Pontiac G6, Montana SV6
2006 Buick Terraza
Equipped with 3.9L (LZ9) engines



This PI was updated to include finding a vehicle for engineering in the Detroit Metro area. Please discard PIP3900.


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Some owners may comment about a low coolant indicator or coolant leaking from the engine. The gasket/seal located between the coolant crossover and the front of the right (rear side) cylinder head may be leaking.

Recommendation/Instructions:

Metro Detroit Area Dealers:

Engineering is looking for a vehicle in the Metro Detroit (Southeast Michigan) area that exhibits the condition. Dealers in the "Metro Detroit" area that have a vehicle that exhibits the condition should contact Jim Kelly at (586) 492-5612. He will assist in making arrangements for Engineering to review the vehicle at your location. Do not perform any disassembly or attempt to clean the area where the leak is present until instructed to.

All Other Dealers:

At the present time the only recommended fix is to install a new currently available service gasket (P/N 12577704). When replacing this gasket it will also be necessary to replace the gasket on the opposite side cylinder head. That gasket is P/N 12590668. Removed gaskets need to be returned. Before installing the new gaskets make sure that the mating surfaces on the crossover manifold and cylinder head are completely clean and that NO OIL or OIL RESIDUE exists. Contact Jim Kelly on (586) 492-5612 and he will supply you with information on where to send the gaskets and he will also supply you with a "parts waiver" for your records. The correct labor operation for this repair is J3527.

This document will be updated when/if new information becomes available.

Please follow this diagnostic or repair 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.