How do I get a glowplug removed that cannot screw out and my VW garage refuses to do it?

I can give you some general Diesel knowledge. Diesels do not have sparkplugs. Instead they have glowplugs. The glowplugs can need changing like a sparkplug, but rely on a timer which heats the glowplugs to atomize the fuel. If the timer circuit does not heat the glowplugs you will get your problem. If the timer is good and your glowplugs are bad, you will get your problem. Each glowplug can be removed and tested by applying power with battery cables, but they can melt if not tested properly. Your mechanic should know how to do this for you. Remove the glowplugs and test cylinder compression to diagnose the engine.

I am not well versed on this unknown engine, but here is something to think about. If you look at the appropriate circuit scheme, there must be a part that controls your Maximum RPM. The Limp Mode is suppose to reduce RPM and Diesels do run at lower RPM than gas engines. Often an engine goes into LIMP when it senses overheating. On some engines, cylinders are deactivated and the dead cylinders are turned into cooling pumps.

Puzzling is the Glowplug warning. This can mean you have a dead short in some glowplugs. This easily can explain starting problems, but your engine will heat the glowplugs for probably 2 minutes or less and then they are off for a cold motor. Even restarting the engine when it is hot will not activate the glowplugs. So I can't see the glowplug problem causing a Limp Mode once you are underway.

It could be engineered to work this way though, and you need to refine the info about the Year, Model, and engine size.

I think I would try to change a temperature sensor, and pull the glowplugs out and test them.

If this is a diesel, the glowplugs are in the heads similar to how sparkplugs are installed.

You should first check several other parts. The glowplugs get their power from a Timer. The Timer sometimes is combined with a power relay or the power relay is separate. The power relay is turned on by a signal from the Ignition switch.

So if the Timer, Power Relay, or power feed off the Ignition switch, is defective, the glowplugs will not work.

Check one of the wires to the glowplugs with a Voltmeter. The Timer will send several pulses to the glowplugs and then need to cool off.

The glowplugs only work for a few minutes for the initial start.

If the above parts are good, then check the glowplugs by removing and using battery jumper cables.

Clamp one to the base of the glowplug avoiding the threads, then briefly touch the top of the glowplug with the other polarity jumper.

Caution--you can melt them. Just observe if one stays dark longer than another. A dark glowplug is bad, a bright glowplug is good. Its all relative.

Please comment on my info.

Hello, The diesel engine relies on Glowplugs for the first start in the Morning or a cold start at anytime.

The Glowplugs themselves can be bad, but there is a Timer which determines how long the Glowplugs will stay on. Before the Timer is a Glowplug Relay which gives the Timer its power to operate. The Ignition switch provides power to the Glowplug Relay.

You disconnect a Glowplug wire, put on a test instrument (either a testlight or Voltmeter) and look to see what happens when you initiate a start. If the testlight lights and cycles a few times like a pulse, then the power supply is good. If not inspect the Timer and Glowplug Relay for continuity

If all the pulses seem to reach the Glowplugs, then most likely the Glowplugs are worn out. Test by removing then and connecting battery jumpers. Briefly touch the top terminal of the Glowplug with the Hot cable after grounding the negative cable on the base of the Glowplug, avoiding the threads.

You can melt a Glowplug. But if you find the Glowplug staying dark, then it is bad. Do this for all the Glowplugs and replace the bad ones. Remember the Glowplug only has the amount of time the Timer gives it to work. So if a few pulses do not make it Glow, then replace it. This should fix you up.

Hello, I operated a Ford diesel through Michigan Winters. There are usually issues with the Glowplug Timer or the Power Relay to it. If not that, then you probably have a bleeddown issue in the fuel system.

If you trace the wires off the Glowplugs, it will lead to the Glowplug Timer and then the next part is the Glowplug Power Relay. If you take off one Glowplug wire and put the Hot lead of a Voltmeter or test light on the wire and ground the other testing device terminal you can test it.

Just place the testing device where you can see it or have a helper observe it. Then try a normal startup. The test equipment should show that power is going through the wire. The power should pulse a few times and then stop. If you have NO power at that point, you need to follow the wiring I mentioned earlier and find out where the power stops. That part should be the bad part. You want to restore power to the Glowplugs.

If the wires to the Glowplugs have power, there is the remote possibility the Glowplugs are burned out. To test them yourself, they can be removed and connected to jumper cables and briefly energized. The Glowplugs that stay dark are bad.

The fuel system is another matter. First try a new fuel filter to replace a water clogged filter. It is also beneficial to find that fuel is in the fuel filter and that it is not dry. If the fuel filter is dry, then you most likely are bleeding off your fuel overnight. This will require testing the fuel line by using either a Vacuum tester or air compressor and removing and plugging one line end. The line should not leak.

Diesels absolutely require the Glowplugs to work and they work shorter periods in hot temperatures. You just have the pulses to heat up the Glowplugs. So if the Glowplugs are weak, it will show up in hot weather too.

As for the Injection pump, there are Electric solenoids in some which sometimes respond to a "tap" to get them going again. This will mean pump repair to finally repair it. A Diesel shop can also measure output pressure, which , I want to say can be 1300PSI. Beyond the capability of an Owner to do himself.

I hope this helps you and I would be very interested to know what you found.

Hello, Its just like changing sparkplugs. First, you should check the timer for proper operation before blaming the glowplugs. The timer is the part where the wires on the glowplugs come from. Its' the Timers job to heat up the glowplugs and there is a Relay which activates the timer.

Once the Timer gets power from the Relay, it sends spark to the glowplugs and measures the amount of juice flowing through the glowplugs. When a predetermined limit is achieved, the Timer shuts down and sets a light on the dashboard that you can start the engine.

If you have a bad glowplug, that cylinder will not fire cold and the engine will miss, run rough , and spew black smoke out the tailpipe. A complete changeout of the glowplugs will solve the problem, but individual glowplugs can be tested and changed independently at a lower cost.

To test a glowplug, you can use jumper cables and apply voltage to the glowplug in limited amounts or you will melt the glowplug. Best to place the negative on the base and avoid the threads. Then touch the top of the glowplug and watch to see how quick it turns bright. Its a matter of comparison, and the darker the glowplug stays, the worse it is.

There is no adjustment on the glowplug, just swap them out and you will be fine. I hope my solution is very helpful to you. You can check the Timer with a voltmeter by removing a glowplug wire and hooking the hot lead from your meter and grounding the other wire on your engine. When you turn the key to the warmup position, the meter should briefly show power.

Follow your glowplug wires towards the Firewall. The glowplug wire goes into a Timer which is suppose to be internally regulated by outside Temperature and feedback from the glowplugs.

When you are in Cold weather, the Timer is suppose to keep the glowplugs on longer. When the engine is fully warm and you shut it off, you will notice it starts up like a gas engine. First you want to remove your glowplugs and check them by using Jumper cables and heating them up.

Be careful because they can melt or distort if on too long. I usually pull out 4 at a time because it is a comparison test and when you find the quickest, brightest glowplug you measure the others against it. When the glowplug stays dark or does not heat as quickly it is bad. Remember when it is in the engine the glowplug only has bumps of current coming from the Timer to warm up.

Once you are confident the glowplugs are okay, try starting the truck. Or for good measure, just change the Timer, but it will add to the cost.

As for the engine light, if you mean the "check engine" light, you can get that checked free at Autozone, Oreillys, or Advance. I believe Advance may be better equipped to test the PCM.

I hope my solutions are very helpful to you and thanks for using this service.

It sounds like your Glowplug timer or the Glowplugs are bad. The reason that turning the Key 4 or 5 times helps, is that everytime you put the Key to RUN or START you are energizing the Glowplug timer and reheating the Glowplugs.

You can check the Glowplugs by removing them and remove at least 1 bank at a time. Get some jumper cables and put the NEG post on the plug without smashing the threads. Take the POS cable and touch the Glowplug till it starts to Glow. You can mess up and melt the Glowplug so watch it. BUT, as you test you will find the bad Glowplugs will not light or will take longer to light up.

This is the reason I said to take out 4 plugs at a time, minimum, because you need to compare bad and good, visually.

The timer is not as easy to test. It is a variable timer and the warmer an engine is, the less time it will work. Obviously if the Glowplugs are not Hot, the timer is cutting off too early. But you check your Glowplugs first. The Glowplugs help to give a Feedback loop which tells the timer to stay on.

The rough idle is because the glowplug is not hot or the compression is bad in the cylinder.

on that car, they had lots of problems with glow plugs and the wiring to the plugs, i would change them every 50,000 miles, there not expensive or hard to change,

If your not good at mechanicing I suggest you take the car to someone that is experenced.
The reason I say this that we have loads of cars into the workshop with glowpugs broken in the head of the engine with the result of us having to remove the cylinder head.
What happens is that the tip of the glowplug breaks in the head when being removed if it is not done properly.
There is a way that we have found that they can be removed easily without breaking them.
Firsty run the car engine until warm, then we pour a little Diesel fuel onto each plug & let them sit for 15mins or so.
Then we remove them with a deep socket 1/4" drive so we don't put to much pressure on them.
they should screw out easily but we turn them out 1 whole turn then back a 1/4 add a little more diesel ( thimble full) & gently screw them out.
If they start to get really tight screw in again a little then screw out again.
The nuts that hold on the wires just need to be nipped up with a small 8mm spanner, but do not over tighten.