I have an issue with glow plugs failing prematurely. Sometimes I can get a year out of a set of glow plugs, but sometimes they start failing after a month. I put a new set in the truck on August 17th and had to replace six yesterday because they were no longer functioning.

The engine is out of a 1984 military CUCV Blazer and currently has just less than 32,000 miles total on the engine. The CUCV wiring was removed when I installed the engine in a 1979 full size Jimmy and I then used the engine wiring loom from a 1985 ¾ ton Suburban. I’ve always used ACDelco 60g glow plugs and installed them using copper based antiseize. Doing a forum search it would seem that most owners are getting two to three years from a set of glow plugs. I would really like to get more than a few months or a year’s use out of a set of glow plugs.

I would check the voltage going to the GP circuit. Make sure that they're getting 12v and not 24v. Next, i would check the resistance through the glow plugs. I bet that the antiseize might be increasing the resistance through the circuit and may be causing premature failure. IIRC, the resistance through each glow plug should be 10ohms but I'm not 100% on that.

I believe good plugs range from .8 to 1.1 ohms

I believe good plugs range from .8 to 1.1 ohms

Yup that's correct. All the good ones i've ever checked were 0.8 or 0.9 ohms. I"ve gotten a few that read 10+ and other that have the resistance kept changing on the meter. All of the ones over 1.0 ohm were either taking too long to heat up or were totally dead.

Sorry guys, I was thinking amps, Not ohms. I knew that didn't sound quite right.

Plus, using an anti-seize compound means you are most likely over torquing the plugs. If you add a lubricant to threads, and then torque them to spec, you're actually over torquing something like 70%. This could result in cracking them...thus shortening their life due to too much/little resistance, or exposure to the "elements". And I agree that it's possible the anti-seize could also be increasing resistance.

Thanks. I'll go out later today and take some readings. I'll test first as is and then pull, clean off the antiseize, reinstall and test again to see what the ohm reading is. Hopefully cleaning up the glow plugs will solve the problem. I was told by two individuals that have 6.2L diesels to always install the glow plugs with antiseize preferably copper based for a good electrical contact.

also, check your controler & solenoid, if the solenoid is stuck open, it could be burning them out, same goes for your glow plug controler :) i prefer to use the cole-herse continuious duty ford solenoid + push button method :)

Also, found a place for the true CUCV glow plugs (12v) that heat the whole body up, not just the tip. There is a place called City Diesel ( http://www.citydiesel.net/ ), and they have em for $8.50 each :) gonna order a set for mine after xmas, it's tore down right now for head gaskets :( and mine is getting everything.

-Jeff

also, check your controler & solenoid, if the solenoid is stuck open, it could be burning them out, same goes for your glow plug controler :) i prefer to use the cole-herse continuious duty ford solenoid + push button method :)

Also, found a place for the true CUCV glow plugs (12v) that heat the whole body up, not just the tip. There is a place called City Diesel ( http://www.citydiesel.net/ ), and they have em for $8.50 each :) gonna order a set for mine after xmas, it's tore down right now for head gaskets :( and mine is getting everything.

-Jeff


the 85 controller is not known for as many failures as the older style controller with the relay on the fender. The controller in the driver's side head would go bad and that can meant the GPs don't work at all, or they could even stick on i suppose. Having stuck on GPs would really shorten the life of them.

GM stayed with that style GP controller from 85 up to the end of the 6.5, with just a change to the relay from 4 to 3 pins for the 6.5s.

As for those glowplugs. They sound like WAP instant heats. I've seen photos and they glow the entire body of the GP. They also burn out and swell in less than a year of normal usage. They've got a terrible track record. Do yourself a favor. Get some Bosch Duraterm part # 80034, put a little Anti-seize(key word is a little) on the threads, install them and forget about them. I've got over a year and a half on my Bosch Duraterms and that's with the 6.5 with extended glow plug time and have had no issues. My buddy put a set in his 97 with stock glow plug time and it fires up perfectly. I have 60Gs in my blazer, and they always need another 10 seconds over factory glow time to get it started.

that's real good to know :) you got a good source online for those ? i gotta change all my glow plugs, out of 8, 2 came apart in pieces ( heads were off thank god), and only one of what was left actually worked. Are they a self limiting? or not.

I still reccomend the push button & continuous duty ford solenoid though :) you can use the regular ones, but i have had problems with them sticking open (i had a ford truck, where the solenoid failed, and i watched my old 93 pu drive itself across the driveway, into the big telephone pole in the yard). Make sure you specify the Cole-Herse ones (best success with them), and get the continuous duty, they range $15-20.00

-Jeff

I found the duraterms at Amazon for 8.89 each with free shipping if you spend $25. I figured that's pretty good getting a set of 8 for $71.12 :-)

The Duraterms are a self limiting Glow plug. I got mine from two local pepboys as they only had 4 in stock per store.

Rock auto should have them too. Not sure on the price but they do have discount codes too.

I have the ford solenoid setup on my blazer to extend the factory glow time with my 60G glowplugs. Not sure if its a continuous duty or not. It was a free solenoid from a friend. When i switch to the Duraterms i don't know if i'll need it anymore or not.

i just reccomend the cole-herse continuious duty ones as i have had more than a few of the regular ones (esp. the EFI ones) fuse together. there are 4 different ford solenoids, and none are rated for more than 15 seconds on a regular basis. the old style ones (barrel with posts on the sides), for the 1 wire starters (big 4ga wire) are fairly good, but have issues. the efi ones (flat posts on front, not the barrel with posts on the sides) are only rated at around 20 amps for 15 seconds iirc.

-Jeff

i dont think you have much to worry about with the old ford starter relay (i have a jeep cj relay, its a ford part and just happened to have an extra new one so i used it) while maybe only rated for a 15 sec shot, they are also rated at about 4-500 amps that the starter draws......i see no issues pulling 80 amps for even 30 seconds, and i doubt anyone waits that long.

Mine is supposedly a Glow plug relay from a 94 powerstroke. He replaced the stock style one with a huge continuous duty relay. I'll be looking into one shortly as well.

i picked up some sort of rv selonoid years ago, that looks identical to the ford telay, but was rated for a more continous use

I am by no means and expert here but I have heard good things about the Wellman glow plugs!

good price on ebay less then $70 a set shipped!
http://cgi.ebay.com/ebaymotors/6-2-6-5L-GM-FAST-HEATING-DIESEL-GLOW-PLUGS-0050_W0QQcmdZViewItemQQhashZitem53dd15a126QQitemZ3 60191467814QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAcc essories

with 4 pin controller with a set of plugs about $125
http://cgi.ebay.com/ebaymotors/6-2-6-5L-GM-GLOW-PLUGS-0050-CONTROLLER-COMBO-1005_W0QQcmdZViewItemQQhashZitem53dd4b1066QQitemZ3 60194969702QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAcc essories

http://cgi.ebay.com/ebaymotors/6-5-L-6-2-L-Diesel-Glowplugs-Glow-Plugs-w-Controller_W0QQcmdZViewItemQQhashZitem2555ba7b63QQ itemZ160352074595QQptZMotorsQ5fCarQ5fTruckQ5fParts Q5fAccessories

Can someone post a wiring diagram for adding a manual button relay set-up? got a 90 Suburban that has the 4 pin and a small module near the driver's hood bracket that is supposed to be a relay! The small module just clicks rapidly and does not start
THanks in advance

I am by no means and expert here but I have heard good things about the Wellman glow plugs!

Can someone post a wiring diagram for adding a manual button relay set-up? got a 90 Suburban that has the 4 pin and a small module near the driver's hood bracket that is supposed to be a relay! The small module just clicks rapidly and does not start
THanks in advance

Wellman GPs are junk IMO. Their track record proves it. Look at SSDiesel's "instant heat" glow plugs. Those are Wellmans, and they had a horrendous rate of burning out and swelling up in less that a year with normal glow plug time. Extend the glow plug time with the SSD instant heat/wellmans and the life of the plugs is dropped way down. Could that have been solved? Of course it could've been solved. But that tarnished record would make me stay far away from them.

Also the Wellmans GPs are not a self limiting plug as far as i know. With any glow plug override, that is quite popular with the 6.2s, you need to have a self limiting plug or you will burn them out with extended glow time.

Why spend $70 on them from Ebay when $80-90 will get you a set of glowplugs with a proven track record. Heath tested the Bosch Duraterm glowplugs and IIRC they left them on for 44 hours in a cutaway of a 6.5 head and they didn't burn out. The 60Gs from ACDelco didn't even last that long. The only reason it was 44 hours was because the staff wanted to go home for the weekend so they aborted the test.

That test shows the superior glow plug, why in the world would you want to go the cheap route on something that if the tip breaks off during removal due to a swollen el-cheapo glowplug you've got to pull the head to remove it or grind it into your piston crown?


I just don't get it. :confused:

As for your glow plug system, it sounds like you've got the 84 and older system. Is there a module threaded into the driver's side head at the rear coolant block off plate?

Does the relay have a pink/red and green wire in a plug attached to teh side closest to the engine? If so ground the green wire and the relay should engage.

my 85 has the single gray 4 pin connection relay at the rear of the engine for the glowplugs. I thought all 85+ trucks had this style. Guess not.

The '85 and later white controller does the job just fine.Have'nt had any issues with it.