Verify Glow plugs working without removing possible?

[SnowDrift]

Is this possible to check for their operation without removing them from the engine? I'm suspecting mine might be giving up the ghost due to some harder than usual starting. They've been in for 9 years - what is an average life expectancy on glow plugs? Mine are AC Delco and would have been whatever the parts dealer found in his parts book.

 

[jrsavoie]

I would get a set of AC Delco 60g's and start pulling and swapping. I usually pull mine every 2 years to give them a visual, a fresh coat of copper coat & reinstall or replace. Mostly replace. If they have any blemishes I toss them and install new.

I buy them wherever I find them. I've actually gotten my best price at Auto Zone.

To test them in the truck it is easiest to have 2 testers set for continuity/ohms/buzzer. I prefer the buzzer so I don't actually have to see the tester. Hook one lead of one tester to the out side of the glow plug controller. Pick a glow plug and pull the spade connector. touch the unused lead of the tester hooked to the glow plug controller to the connector you just pulled. This will tell you if the juice can get from the controller to that glow plug.

Next put one lead on the glow plug spade and the other to ground. Should be a maximum of .02 ohms of resistance or the buzzer should sound. The tester should read the same as if you touched the 2 leads together. Sometimes you have to scratch with the tester leads to get a good connection.

In your case with glow plugs that old, I would just start replacing them, being careful not to break them off. Definately use some penetrating oil. I try to clean the area so nothing gets knocked in the hole while the glow plugs are being changed

 

[Dieseldad97]

When I replaced my glows, I would take the truck for a good rip to heat the engine up good and proper. I also prayed before the removal process. I know these two things helped. Don't forget to put anti-seize on the new ones.

edit: I always checked mine with a battery charger. I know it's not the best way but it worked for me.

 

[jrsavoie]

Warming the engine was something I forgot to note. I frequently plug mine in for a couplr of hours before working on it. Sometimes I plug it in and wait if I am having trouble with something.

I've had especially good luck doing this with the oil filter adapter for 4x4's. This was suggested to me some time ago by one of the geniouses on this forum. Sometimes it's the little tricks that makes things go smooth

 

[SnowDrift]

I've read about the Duraterms, too. Are these more talk than walk?

Thanks for the tips, guys. I can't remember a job like this and not praying beforehand, in earnest - not in a panic. I hadn't thought about heating the engine - what's the reason for doing this, other than just that things are nicer to work on when they're warm when it's cold out?

 

[jrsavoie]

I use 60g's because that's all I have used. They have worked for me and I've had no problems, so I have had no reason to try anything else.

I think I have at least one glow plug that needs attention on the 94. As soon as I am able I will have to do what you're doing.

The warming the engine accomplishes the same thing as heating a nut with a torch. On a much smaller scale but often times it is just enough to make the job much easier.

When removing the oil filter adapter I couldn't break it loose with a breaker bar. After warming the engine for 2 hours it came right out.

 

[great white]

I've read about the Duraterms, too. Are these more talk than walk?

Thanks for the tips, guys. I can't remember a job like this and not praying beforehand, in earnest - not in a panic. I hadn't thought about heating the engine - what's the reason for doing this, other than just that things are nicer to work on when they're warm when it's cold out?

I've got duraterms in mine.

No complaints and no failures but it's only been a year.

Don't forget to get a 10mm deep socket to remove/install them.

 

[ak diesel driver]

I'ved noticed my duraterms heat up slightly faster

 

[jrsavoie]

Some glow plugs are 7/16 or 1/2"

 

[WarWagon]

The old plugs were known to swell up and require injector removal to get out. There is no "lifetime". Recommended to change with injectors. I have seen working original plugs in 1986 6.2's (30K miles) as well as 1993 6.5's with 125K on them.

The new plugs, slow heat 60G's or faster heat Duraterms are still "colder" than the original 9G's. Colder is from the limited glow time the controller provides: the original plugs would get hotter IMO. You can leave the power on longer with the self limiting plugs where the originals would burn out. I regularly double cycle the ignition on the 1993 on Duraterms with a aftermarket replacement glow plug controller to heat them up enough for a smooth start. The factory unit had lost some glow time and would not allow a double cycle. I also crank just before the light goes off the 2nd time so the plugs will stay hot if it fails to fire the first few times from air etc.

I verified glow plug by pulling an injector and looking down the hole to see if the plugs would glow and maintain the glow during the after glow cycles. The aftermarket controller does a poor job of that.

My 1995 has a different tune to extend glow time.

I have had better luck with duraterms only because I turned the 60G's to burnt off stubs from insane egt's, engine failure, along with ether use to start a failed engine. I also feel the duraterms get hotter in the limited glow time than the 60G's.

 

[bhelms22]

I changed my glow plugs to Duraterms when I replaced my injectors for about $7.50 each (if I remember right) from rockauto. I don't know if all mine were working or not before I swapped them but I noticed the truck did start faster. For some reason I have it stuck in my head that I had to use a different socket for the Duraterms than the AC Delcos that were in it.

 

[L98TPI]

For what its worth and I realize few are going to have the gear, here is how I test glow plugs.
Power source: 50 amp 12v (13.8) regulated power supply. batteries and chargers wont do. the voltage has to be regulated to make good comparisons.
Amp meter: DC clamp on or a regular meter capable of taking the short current of the power supply without burning up
Heavy duty clip leads

Take a sample new plug the same type that in the engine and measure its current draw. Without changing the lead lengths check the current draw of each plug in the engine in place.
Rarely do plugs have the spec current draw (say +- 5%) and are not working correctly. I have seen high current draw plugs that were barely glowing red and soon to die.

Also I have done a quick check with a clamp on DC meter while they were cycling and quickly found a dead one.

If you do the above test out of the engine you can time how fast they come up to temp and where the heat is concentrated. If they start failing inside the heat from the element does not get to the shell evenly. An indication they are not long for this world. Look at a few new plugs and you will get the picture of where the glow should be centered on the shell and how quick they should heat.

Measuring the plugs resistance with a multimeter only useful if its failed open as they often do but that's it. the resistance is so low its nearly the same as shorting the leads together.

Wear eye protection. I had one blow up in my face like a squib and shoot its ceramic filler and nicrome wire shrapnel on me.