Glow plug socket size? 3/8 or 10 mm?

[93fordturbo]

i just bought some plugs and put em in, plus a controller and new selenoid. Everything works great, but my buddy and i had a little dispute. I say that the glow plug size is 3/8 and my buddy said it was 10mm. I put a wrench and a socket of each size on the plug, and 3/8 was tighter. not too tight though. 10mm was a little loose. what is the true size? Thanks

 

[TWeatherford]

I've always heard 3/8. Bought a 3/8 specially for that, though 10mm has worked for me in the past. Most socket sets stop at 7/16 deep well.

 

[rhkcommander]

depends on who makes em' so your both right.

Some are standard, some metric. My bosch were 3/8, just pulled my friends glow plugs and they were some I-talian brand 10mm. Plus if you try that 3/8 on a 10mm glowplug you'll find it dont work, 3/8" ~= 9.5mm

 

[TWeatherford]

I just assumed no one here would be putting anything but Motorcraft/Beru glowplugs in their truck. And they should all be 3/8.

 

[Brimmstone]

3/8 is what I use all the time.

 

[Goofyexponent]

1/4" drive!!!! You do NOT want to twist these off!! If they get stuck, wind them in and out until they come all the way out. Do NOT force them!!

Copper Antiseize on new ones, and do NOT over tighten!!!

 

[OLDBULL8]

1/4" drive!!!! You do NOT want to twist these off!! If they get stuck, wind them in and out until they come all the way out. Do NOT force them!!

Copper Antiseize on new ones, and do NOT over tighten!!!

Your wrong on this Goofy. That is the antisieze.

http://www.beru.com/english/produkte/gluehkerzen/diagnosehilfe.php

Attention

The threads on all BERU glow plugs are nickel-plated. In this way seizing of the glow plug is reliably prevented. Thus, under no circumstances oil or grease the thread!

 

[Goofyexponent]

What happens if you antizeize anyways? I guess I will let you all know this spring!!

Thanks for the correction though!! I am still learning!

 

[TWeatherford]

Pretty much everyone here seems to recommend never seize for the glow plugs, including me. That certainly doesn't mean its correct to do so. This is interesting, I don't see what kind of harm it would do unless the anti seize reacts with the nickel plating and causes them to be stuck worse.

 

[93fordturbo]

so 3/8 is final conclusion??

 

[jonathan]

i used a 10mm and it worked great

 

[icanfixall]

I also use anti sieze on the threads but very little of it. Never allow any material on that crown just below the threada. Thats the only part of the glow plug that actually seals in the head. The threads do nothing about creating a seal surface. they just hold the plug against the seat in the head. Kinda like a pipe fitting union. You have the thread half and the ring half. Only the taper part seals in the ring half. The actual ring only holds the two halfs together. It wont seal any leaks. When I was working in a chemical refinery I found teflon tape all around the ring half threads. Some ****** was trying to stop a union from leaking in a system... Not very bright guy right there....

 

[rhkcommander]

as I said:

3/8" is more correct but a 10mm will work on a 3/8. There are 10mm glowplugs that can fit into the heads .

And a 3/8 socket wouldn't fit onto a 10mm glowplug as I explained above.

 

[Diesel JD]

I seem to have had better luck with a 10mm socket. Always have had Beru, SLM or Delphi glow plugs in the truck. Never any anti-seize compound on any of them and they have always come out pretty easily.

 

[Logic]

If you said 3/8 **** you