Carbon buildup on the top of the piston is common. Over time this can lead to symptoms varying from light ticking to knocking noises. Performing a fuel injector cleaning procedure can often help the condition by removing some of the piston top deposits.
Car problem reports
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Newest reported 1990 Dodge D150 problems
The AC/heater (HVAC) system may unexpectedly switch to the defrost mode when accelerating. This system is operated by engine vacuum and should be inspected for any vacuum leaks if this problem develops. There is also a revised vacuum check valve available to address this concern.
The blower motor may operate erratically and the blower switch operation has a sticky or mushy feeling, the detents almost non existent. Our technicians tell us that the blower switch should be removed and inspected for overheating. This is common if the blower motor is frequently operated on high speed as the current flow through the switch tends to melt internal the components. Also carefully inspect all of the switch connector terminals for discoloration due to overheating and replace as required. A poor electrical contact at the connector will also cause the switch to overheat.
The powertrain control module (PCM) may fail resulting in a lack of AC cooling. The lack of cooling could be caused by evaporator freeze-up due to the AC compressor staying on continuously or conversely, not coming on at all. Proper diagnoses of the PCM should be performed before replacing it for this concern.
Vehicles equipped with 12" diameter rear brakes may encounter premature rear brake shoe wear. If it is found that the brake system is functioning as designed the repair would be to replace the affected brake shoes with revised parts.
Oil leaks from the valve cover gaskets, timing cover gasket, distributor o-ring, and rear main seal area are common. The leak at the rear main seal area is generally not the seal itself but the bearing cap to the engine block seal. An oil leak could also be internal to the distributor, if oil is found inside the distributor then the distributor should be replaced.
The fuse may blow repeatedly for the HVAC blower motor or the motor may stop working all together. Our technicians tell us that can often be repaired by replacing the blower motor switch with a revised switch and installing a wiring harness with a relay assembly.
Cracking or popping sounds from the cowl area may be a result of cowl cracks at the lower corners of the windshield. The fenders must be removed to see the cracks. If cracks are found, a reinforcement kit is available to correct the condition.