Testing glow plugs

[arlen4720]

an extreme redneck hillbilly quick check is to see if the headlights dim when you activate the glow plugs. You can't diagnose individual plugs, but it'a a good quick check of the control circuit and to see if all the plugs are burnt out.

 

[PILOON]

A glow plug is basically a resistor so the ohm test is just fine.
They should all read the same value or real close. Different tractors with different plugs would give different values, but all low.
Just don't forget to remove each lead in order to get individual readings.
In many cases just removing and replacing the leads might just cure your problems due to bad connections.
High amp connectors like glow plugs and battery terminals need to be clean and corrosion free. (grounds also).

 

[coloradotrout]

Update - I replace all 3 plugs with the ones I noted above from Amazon. Exact fit. $8 each with free shipping once my wife added in some Christmas gifts!

Remove the air filter assembly (loosen hose clamp). Remove the muffler (3 bolts - add some PB Blaster). Remove the metal bracket that the air filter strap connects to. That gives you clear access to 3 plugs.

Last eve it was about 35F. The daytime was around 40. Usually this would present a starting problem for me. Remember, I removed my timer (the failing component). I put into L, turned ON the ignition for about 20s, put into N, and it fired right up like it was 80F outside.

My guess is that timer -- which left 12V continuously applied -- burned out all the plugs, and I've been "cranking" for years not knowing my plugs were dead. I don't plan to replace the timer. The manual approach is just fine and gives me more control.

 

[alchemysa]

If they are bulged at the tip then they are definitely shot. (But thats doesn't necessarily mean that if they are NOT bulged they are fine.)

 

[Norm W]

A test lamp won't tell the truth as it will light with a bad plug. If you make a test lamp from an old head light the amp draw is high enough to give you the truth. If the end of the plug has bulged out you might not get it out of the hole. The fix for that is removal of the head and more work than you probably want.

 

[coloradotrout]

A test lamp won't tell the truth as it will light with a bad plug. If you make a test lamp from an old head light the amp draw is high enough to give you the truth. If the end of the plug has bulged out you might not get it out of the hole. The fix for that is removal of the head and more work than you probably want.

For $8 each -- and the time it takes to get to them. If the engine starts hard in cold weather -- replace them all ;-)

 

[topstoy]

Another way to test is to use one of those lazer thermometers. and spot on each glow plug to see if they heat up..

What about touching the glow plug while heating, can you feel any temperature from the outside of the plug? Never tried it but thinking I might for a quick check. My 2520 seems like it is initially firing on only 1 cylinder for 3-4 seconds. Sounds bad!!!