1998 GMC 2500 Pickup Problems
RepairPal has identified the most common problems with the 1998 GMC 2500 Pickup based on complaints from actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.
The 1998-2000 GMC 2500 has a known issue with the air pump check valve which causes illumination of the check engine light. There are no notable symptoms, but the vehicle will not pass state inspection or smog testing.
When the valve fails, it sticks closed, and the computer sets the code P1416. Replacement of the check valve is the only fix, as the valve is not serviceable.
The headlight switch used on the GMC Sierra 2500 is known to fail through normal operation. Since the headlight switch is also integrated into the interior lights, a malfunctioning switch can cause issues with interior lights as well.
- Symptoms of a failed headlight switch include:
- Headlights and taillights failing to turn on or off
- Interior lights flicker, or fail to turn on or off
- Gauge cluster lighting off or flickering with headlights on
- Parking light malfunctions
This issue is well known with General Motors Trucks and SUVs, and is solved by testing and, if needed, replacing the headlight/dimmer switch. Bad grounding wires at the tail-lights, and dirty/corroded tow package wires can also lead to some of these issues.
Illumination of the Check Engine Light can be caused by a loose or worn gas cap.
The spark plugs should be replaced every 100,000 miles. Our technicians recommend replacing the spark plug wires also at this time.
Vehicles equipped whit a 4 speed automatic transmission may develop a harsh 1-2 shift and/or illumination of the Check Engine Light with code P1870 stored. This can be caused by wear of the bore for the TCC isolator and regulator valves in the valve body. This condition does not commonly occur until the transmission reaches normal operating temperature. If the valve body is worn, replacement will be necessary to correct this concern.
Our technicians highly recommend that the transmission is serviced every 30,000 miles to avoid problems and maintain optimal operating order.
The quick-connect fittings for the heater hoses tend to leak engine coolant. This problem commonly occurs because the metal housing has become brittle, which can break and cause leaks.
The alternator may fail causing the battery to go dead, or an abnormal noise may develop. The dash warning light may or may not illuminate. A failed alternator will require replacement.
The air conditioning compressor may develop an abnormal noise and require replacement. We recommend that whenever an AC compressor is being replaced for a noise condition, a filter kit should be installed to prevent any metal particles in the system from damaging the new compressor.
A coolant leak may develop from the water pump. This can result in an engine overheating condition. A leaking water pump will require replacement.
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. Running the engine with a coolant/oil mix may result in engine damage. Replacing the intake manifold gasket should correct this issue.
Power brake systems using "hydro-boost" may leak power steering fluid from the hydro-boost unit located behind the brake master cylinder. Replacement of the hydro-boost unit is the common repair to correct this concern.