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duramax glow plug problem

11K views 21 replies 8 participants last post by  brooks294x4 
#1 ·
so when i studded my truck, i had a glow plug break in the head and sent to the machine shop to get removed. they told me it didnt mess up any threads and and i didnt need a helicoil, but now im having a problem with the glow plug workin loose when i drive it. i tightened it last night and drove 8 miles to my buddies house and i could hear compression leaking at idle when i got there.

at the moment, pullin the head isnt an option. im gonna get a new glow plug with fresh threads and run a tap through it and try that. anyone have a problem like that or recomend a good high heat/high pressure threadlocker they could recomend. if all else fails i will helicoil it but gonna try to avoid that.
 
#4 ·
maybe a very tiny bit if you put some grease in the flutes to catch the bulk of it.. plus, a little bit of aluminum aint gonna hurt it.
 
#7 · (Edited)
did plan on greasing the tap so i catch shavings. then diabling the injector and cranking with the glow plug out to blow out whatevers left.

i work at a GM dealer and know all about time serts, but was gonna try to not drill and put too many shavings in there
 
#8 ·
Check the head near where it tapers for the electrode. There may be a burr or something not allowing the plug to be torqued properly. Just a thought, I've never had one come loose on its own, but have removed dozens of broken Dmax glow plugs without having to tap the head. Only done that once. You can get 90% of them out without removing the head. Its tedious but possible.

Also, there is no timesert available that will match perfectly, you will have to re-thread the plug to match.

For the locktight, its up to you. Sure, it wont come loose, but if you ever need to replace it again, it wont come loose.

I wouldn't chase the threads with a tap, you run the risk of opening up the hole even more. Like Rouphis said. If the hole is already loose, you will only make thing worse.

If the head looks ok, try a wrap of teflon tape to tighten things up.
 
#9 ·
well i need to figure out whats up with it now, i was driving last night after i tightened it up again and blew the glow plug completely out of the head. put the 4 ways on and limped it the 1.5 miles home, and was pissed so i didnt even look at it and jumped in my car and left. looks like some research and a good look at the head is in order for this one.

any suggestions are appriciated.
 
#10 ·
when they drilled out the old plug they got into the threads.
You've retorqued it a few times and probably started pulling the threads out.

glo plug stripped the threads and has left the building.

you're doing the timesert thing I would guess.
 
#11 ·
pretty much what i figured. ill probly get into it tomorrow and go from there, hopefully we have so time serts at work that will fit.
 
#13 · (Edited)
Try using hydraulic pipe sealant. Basically looks like a white RTV tube full of white teflon tape goo. I forget full cure time, but, it when I have used it for brake jobs I let it sit for 24 hours. It "should" hold up to the heat on the head, but, I never tried it in that app.

Something such as this:

http://www.seton.com/loctite-545andtrade-thread-sealant-hydraulic-pneumatic-fittings-25t.html

Though mine came in a big tube, not a little bottle. For your app. I would apply to the head threads with a Q-Tip, then lightly coat the injector threads, and then screw the injector in.
 
#14 ·
http://www.ebay.com/itm/NEW-TIME-SE...H_DefaultDomain_0&hash=item46027404c9&vxp=mtr

took a new glow plug for my truck, 04.5 LLY, and measured the threads, it they are M10 x 1.25. our dealer does not stock this particular repair kit but it is available. im gonna order one tonight and well see how it goes when i get it.

and yes the threads are gone completely in my head. i retightened it again today to move my truck to mow grass and it blew out again in about 5 seconds.
 
#22 ·
my time sert kit came in friday afternoon, but of coarse i wasnt expecting it til monday so i didnt bring home the tools to do it. ill take a few pics and post up monday after work when i put it in.
 
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