B7200 Glow Plug Removal and Test.

[cb750k8]

Want to test glow plugs. Tractor will start after taking off compression and preheat (I count up to forty!) but I feel it could be better and winter is coming.

Two questions.

1)Is there a smart way to remove glow plugs. It looks like I will have to remove the air intake manifold and some diesel lines?


2)I have checked the manual and cannot find anything on electrical testing. Does anyone know what current in amps should flow to each glow plug? Has anyone done this test?

Thanks

 

[Kennyd4110]

Removal is not necessary to test them, just a good ohm meter is needed. Remove the electrical connection at the top of the plug, touch one lead of the meter to a good ground, and the other to the glow plug where the connector was just removed. A reading of near zero ohms indicates a good plug, and a reading of infinity means it's "open" and needs to be replaced.

 

[Stubbyie]

On at least some models the connector strip that ties all the glowplugs together 'electrically' is literally a strip of metal, not a cable.

When removing the entire electrical connection strip, be certain not to lose the tiny nut on top of each glowplug. Seems like it's an odd size, had to use a miniature metric angle-head ignition wrench after breaking it loose with the box-end of the same wrench. Soak first with Kroil, then blow clean before removing---if the glow plug itself has to come out.

I've had decent luck when interviewing used iron by just holding a fingertip to the glowplug when it's heating. Should be able to feel it warming up or if there is a difference one to another.

Another consideration: If one glowplug is completely dead, the controller (or coil, if mechanical) may be trying to pass too much current (for instance 'seeing' two instead of three glowplugs) and may suffer a shorter life. There have been some related threads aboard this Forum if you search the topic.

Depending on machine hours, if you have one dead glowplug, I'd be inclined to change 'em all. Twenty years from now you can do it again.

Please post back your continuing experiences so we can all learn.

 

[cb750k8]

Hi
Thanks for replies
Did the resistance test on one glow plug and it checked out OK. Resistance was 1.5 ohms but my multimeter is a cheap one and I have no faith in it's accuracy. I will post results of tests on three glow plugs when I find a suitable spanner to remove the other two plugs.
Found info attached on replacement glow plugs if needed. All dimensions checked out against my glow plug.
Thanks for help