PDA

View Full Version : How exactly do you test glow plugs with a multi-meter for me NCV3?


fink1741
05-03-2013, 02:50 AM
How exactly do you test glow plugs with a multi-meter for me NCV3? I want to go the route of replacing only bad glow plugs and I'm not sure how I would test them in order to find the bad ones.

So with that said, what multi-meter will I need to purchase and how to set it?
I'm not sure if the red lead from the multi-meter goes to the positive side of the battery and then touch the black to the top of the glow plug and look for 4.4 volts.

Thanks

Eric Experience
05-03-2013, 11:47 AM
Fink.
You can use any brand of multimeter. Most meters come with basic instructions. If you have no experience working on vehicles you may find getting the clips of the tops of the glow plugs without damaging them a challenge. You should test the glow plugs with the key switched of using the ohms range. Eric.

671
03-24-2014, 01:34 AM
For future reference, below are two good YouTube tutorials.

The first is generic for resistance testing glow plugs out of the vehicle. The second is specific to VW, but shows how to do a resistance test without removing the glow plug; placing the negative meter lead on any convenient good ground saves a lot of hassle.

http://www.youtube.com/watch?v=4Po_1pNHE1Y

http://www.youtube.com/watch?v=Fcqwi0mnl_Y

jdcaples
03-24-2014, 02:04 AM
In case it wasn't made crystal clear by Eric Experience, do not try to fire the glow plugs with 4.4 volts DC current.

-Jon

flman
03-24-2014, 10:45 AM
How exactly do you test glow plugs with a multi-meter for me NCV3? I want to go the route of replacing only bad glow plugs and I'm not sure how I would test them in order to find the bad ones.

So with that said, what multi-meter will I need to purchase and how to set it?
I'm not sure if the red lead from the multi-meter goes to the positive side of the battery and then touch the black to the top of the glow plug and look for 4.4 volts.

Thanks

Why not just buy an OBDII reader and let it tell you what glow plug to replace? Sounds like a lot of extra work to unplug them all and reach in and test them?

And be sure to remove the bad one while the engine is hot to prevent it seizing and breaking off.

6cyclone6
03-24-2014, 07:38 PM
The best way to test them is with an inductive amp clamp. No removal, and you can see weak ones, or (not too common on the om642) if there is carbon buildup.