The intake manifold gasket may develop and external engine oil or coolant leak. In some cases, an internal coolant leak may occur causing coolant to mix with the engine oil. Our technicians tell us that operating the engine with a coolant/oil mix can result in internal engine damage. Replacing the intake manifold gasket should correct these leaks.
Problems for specific Chevrolet Monte Carlo years:
Car problem reports
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Most reported 1999 Chevrolet Monte Carlo problems
The high pressure power steering hose will commonly leak fluid; it should be replaced.
The serpentine belt tensioner pulley may wear out. Our technicians tell us that in order to get a new pulley from General Motors you must purchase a complete belt tensioner assembly.
The fuel pump may fail causing engine to stall and not restart.
The mass air flow or crankshaft position sensor may fail causing the engine to intermittently stall. It may be necessary for the engine to cool down before it will restart.
One or more of the power windows may stop working due to a failed window switch. Failed switches will require replacement.
An engine oil leak may develop from the rear of the engine. This is commonly caused by a failed oil pump drive o-ring seal. The leaking o-ring should be replaced to correct this concern.
The intake manifold gasket may develop external engine oil leak. The manifold gasket will need to be replaced to correct this issue.
The upper intake manifold gasket and/or a PCV vacuum lines/hoses can develop vacuum leaks with age. This type of leak can result in a higher that normal or rough idle.
The crankshaft position sensor, ignition module, and/or powertrain control module (PCM) may fail resulting in illumination of the Check Engine Light with ignition system related fault codes stored in the PCM. Patience is necessary when dealing with this specific situation as normal diagnostic procedures are not effective. In many cases, the best option is to replace parts, one at a time until the fault is corrected.