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2004 Pontiac Bonneville Problems

RepairPal has identified the most common problems with the 2004 Pontiac Bonneville based on complaints from actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.

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22
Known Problems

The intake manifold gaskets can develop external engine oil or coolant leaks. The intake manifold will need to be removed and the gaskets replaced to correct this issue. In some cases the plastic intake manifold my be damaged requiring replacement.

You may be able to prevent transmission problems by servicing the transmission and inspecting the fluid every 30,000 miles. If the fluid is dark or burned then the transmission system should be completely flushed.

The spark plugs should be replaced every 100,000 miles. Our technicians recommend replacing the spark plug wires also at this time.

The engine may develop an oil leak from the lower crankcase portion of the engine block. Our technicians tell us that the engine must be removed from the vehicle to properly repair this oil leak.

Our technicians recommend flushing the brake fluid every 60,000 miles.  Brake fluid that is dirty may cause problems in the brake system.

The water pump and/or the plastic side tanks on the radiator may leak causing a loss of coolant. The engine may overheat due to coolant loss. Continued coolant loss after external leaks have been repaired could indicate a blown head gasket.

Overheating of the engine may cause the cylinder head to expand, severely straining the head bolts and damaging the threads in the engine block. This commonly results in a blown head gasket. Our technicians tell us the engine block threads must be repaired before the cylinder head is reinstalled.