I purchased 8 AC 12G glow plugs and tested them with my battery charger before trying them in my truck. I used a 10 amp battery charger (no boost for starting a vehicle) with the black lead on the threads and the red lead on the blade connector. I held the red lead on the blade for about two seconds and the GP started to smoke. I then took the lead off and waited for about one minute. I then put the lead back on and held it for about 10 seconds. After 10 seconds about half of the glow plug end was red hot and then every single one of them exploded. Needless to say, I will be looking for a different brand of glow plugs.

 

You need to them back and get your money back. Don't take no for an answer either.

 

Aren't the AC 12G GPs dual coil, which can be kept on for an unlimited amount of time? What do you think happened? Moisture? Just bad plugs?

 

motorcraft/ beru glow plugs.
ZD-1 for 6.9, ZD-9 for 7.3, and ZD-11 for powerstroke.
rock auto has all 3 for $9.82 each.
why pay more for inferior junk when you can but the recommended glow plug for less??

 

I had a set do that same thing. I know for a fact that the 12G should be able to be heated for hours with a 10 amp charger. If they exploded, they absorbed moiture form the atmosphere. No telling how long or where they were stored. When I got the replacement set, I heated them until the oil film smoked set it aside and did the next one. After all were heated this way, I then left the power on until they were cherry red. After that all was good. No problems. In fact I have drained my batteries twice because the GPs stayed on. After the second time, I found a grounded wire causing the problem. Thank goodness I had the 1109s (1109s are the same as 12Gs, both made by Wellman) in there.

 

How much heat can the upper part of the glow plug take? How about putting them in an oven for a 2-3 hours at 200 degrees before either putting them in the truck or trying them with a battery charger? I would think that would take care of any moisture problems they have. I have a set of 088 Wellman GPs on the way here. 088s are dual coil and are Wellmans version of both the 1109 and the 12G. (Wellman now sells their GPs under the DieselRx name)

Have you had to replace any of your 1109s? If so, when you have pulled them were the tips swelled?

 

They haven't failed yet so I don't know. As long as you don't put more than 12V on them they will not swell up after the initial full heating. You can bake them in your oven up to 250 F. I'd do 220 F for 2-3 hours. I would still heat them up with your battery charger before installing them. BTW, all 3 #s are the same part.

 

https://www.ford-trucks.com/forums/1...fter-test.html

https://www.ford-trucks.com/forums/6...the-6-9-a.html

https://www.ford-trucks.com/forums/6...low-plugs.html



this just can't be said enough, hey tjc.

 

Call me a stubborn old fool, but mine will never see anything but the berus. I know what it is like pulling a head while it is still in the truck. But then again I have never used any thing but Motorcract spark plugs either in any gassers I have owned.

 

Some people learn the hard way and some people learn the easy way. The easy way is to listen to those who have learned the hard way.

After reading on here from those who learned the hard way I checked my GP's and found they were Autolites. Even though they were all newly installed from the PO I took them out threw them away and put in the Berus. I'm glad I did because my Berus got fried and I dread to think what would have happened if I had left the Autos in there.
There will never be anything but Berus in my truck!!