What is the resistance limit for good glow plugs?
 

For an om617- what would the upper limit be? I have a few plugs that are testing at 4.5 to 6 ohms (engine warm, if that matters) and want to know if I should replace them.

Thanks.

1.5--2 ohms is what I've seen stated before. Yours seem high to me. Best way to check is to pull them out and put 12 volts to them.

JUST BE CAREFUL
 

Do NOT touch the glow plugs!!!!

As the get hotter the element reistance of the glow plug increases. If you are getting say 1 ohm readings on some plugs and at the same time basically 4.5 ohms or so on others.

It is a pretty sure thing you have to examine things more carefully. Since there may be variables present. Pulling them and doing a direct voltage test application for observation may be best.

If a plug and its feed wire from the timer box is showing 4.5 ohms something is not normal.

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you have to be precise
first do you meter correction readings
(probe wires head to head)

I practice to change any above 1 ohm - measured cold GP only.


from your post I would say that you have those 6 ohm to change :(

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