How to Troubleshoot a 1998 VW Jetta 1.9L Diesel
The 1998 Volkswagen Jetta 1.9L diesel was one of the most reliable vehicles that Volkswagen offered. The diesel engine from Volkswagen does have one flaw, however, and that is one inherent in all diesel engines: cold-weather problems. Cold weather and malfunctioning glow plugs are the cause of most of the VW diesel's problems.
Other People Are Reading
Instructions
-
-
1
Check for colored smoke coming out of the tailpipe. Blue smoke indicates an internal oil leak caused by oil blowing by the piston rings or a failure of the valve cover gasket. White smoke indicates a head gasket failure and engine coolant burning in the combustion chamber. Both of those can be very serious and need to be fixed by a professional mechanic right away.
If the problem is that the engine won't start in cold weather, then the most likely problem is with the glow plugs.
-
2
Turn the key to the "II" position to verify that all systems are working normally. Make sure that no service lights stay on.
Remove the key from the ignition and open the hood. Disconnect the negative battery cable.
-
-
3
Remove one of the glow plug wires on the top of the engine by pulling it straight up out of the engine.
-
4
Attach the glow plug socket to the socket extension and lower it into the plug well. Orient the socket until it grabs onto the glow plug. Turn the socket and extension (and glow plug) counterclockwise with a socket wrench to remove the plug.
-
5
Examine the electrode on the end of the plug. If it is malformed, damaged or missing, then you must replace the plug.
-
6
Put the plug back and repeat steps 3-6 for all glow plugs.
-
7
Reconnect the battery cable.
-
8
Check for rough idle. That can indicate a multitude of issues from low compression in one of the engine cylinders to a faulty EGR valve. You can check the EGR valve by opening the hood and looking at the valve mounted on the back of the engine on the manifold. When you rev the engine, you should see the small plunger move back and forth. If you don't, the EGR valve has failed. Those valves can get quite dirty on the Jetta's diesel engine due to the nature of diesel fuel.
-
9
Check for hesitation at low RPM. That can be indicative of a clogged fuel filter or clogged fuel injectors.
Because diesel fuel has different characteristics than gasoline, the filters can become clogged much sooner on the Jetta diesel than on it's gasoline counterpart.
The injectors, if dirty, will need to be serviced by a professional mechanic.
-
1
