HMMWV glow plugs

mgFray

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Just needed to vent.. Figured it might be useful to other people having this issue...

The smart start box of course stopped powering the glow plugs. It's getting cold, so why would it work.

Ordered a new box and 8 new glow plugs. Read on forums here and elsewhere I should get a removal tool cause often the glow plugs in the engine are swollen and need a puller tool. Ok, ordered. (From leroydiesel...)

Get the tool.. built for 3/8 hex head.. new glow plugs 3/8 hex head.. Go out to the HMMWV to start swapping the parts and...

The glow plugs in the engine have 10mm heads and are swollen, so I have no tool to remove because it doesn't fit. ARGH!

So now, I have the OTC 6005A glow plug removal tool ordered.

So what is the deal with 10mm vs 3/8" head glow plugs?! Where did this 10mm size come from?
 

Mullaney

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Just needed to vent.. Figured it might be useful to other people having this issue...

The smart start box of course stopped powering the glow plugs. It's getting cold, so why would it work.

Ordered a new box and 8 new glow plugs. Read on forums here and elsewhere I should get a removal tool cause often the glow plugs in the engine are swollen and need a puller tool. Ok, ordered. (From leroydiesel...)

Get the tool.. built for 3/8 hex head.. new glow plugs 3/8 hex head.. Go out to the HMMWV to start swapping the parts and...

The glow plugs in the engine have 10mm heads and are swollen, so I have no tool to remove because it doesn't fit. ARGH!

So now, I have the OTC 6005A glow plug removal tool ordered.

So what is the deal with 10mm vs 3/8" head glow plugs?! Where did this 10mm size come from?
.
Well, let me stir the pot for you on that. Back in the dark ages when the dinosaurs roamed the earth, back when you had to walk to school UP HILL in the snow in both directions - there was an Engineer. Back in the late 70's and early 80's this Engineer figured out that in the brass fittings there was money to be saved by using less material. Didn't matter that every mechanic in this country had to buy a set of METRIC line wrenches and all the other pieces that were required to rotate fittings and bolts. I remember MANY crushed brass fittings happening as "a thing" and it didn't cost the Engineer a single dime...

To be honest, what you are seeing or experiencing is just more of the same - 30 years later.

You most likely are seeing the OEM vs an Import part with 3/8" against 10mm
 
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Action

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Just needed to vent.. Figured it might be useful to other people having this issue...

The smart start box of course stopped powering the glow plugs. It's getting cold, so why would it work.

Ordered a new box and 8 new glow plugs. Read on forums here and elsewhere I should get a removal tool cause often the glow plugs in the engine are swollen and need a puller tool. Ok, ordered. (From leroydiesel...)

Get the tool.. built for 3/8 hex head.. new glow plugs 3/8 hex head.. Go out to the HMMWV to start swapping the parts and...

The glow plugs in the engine have 10mm heads and are swollen, so I have no tool to remove because it doesn't fit. ARGH!

So now, I have the OTC 6005A glow plug removal tool ordered.

So what is the deal with 10mm vs 3/8" head glow plugs?! Where did this 10mm size come from?
Do the swollen plugs in your engine have spade or bullet connectors on the ends?
 

Milcommoguy

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This is how I do it. No fancy tool... just a good pair of Vise Grips. 3/8 socket gets it loose. If swollen a squirt of oil in the hole. Vise Grip locked on the glow plug head, tight not crushing. Pulling hard with a controlled feel and rotate 1/8 turn clockwise, then counter clockwise. Repeat as needed. The deal here is to draw and re-shape the split stem back thru the bore. Stay true to the bore as to not snap the tip completely off. Slow and easy as you go, oil as needed, watching progress, holding breath just right.

I have pulled a bunch this way. When out, inspect to see if extra parts were left behind. Not sure or ??? No problem here too. A little more work to pull the injector (and lines) and fish the extra parts thru the big fat injector port. Next with a blast of air down the glow plug hole and crud coming out the injector port. Safety glasses a must. Bullet proof vest optional.

Story time... when I had all the injectors and plugs out...got the big idea💡 to blast air into the plug holes. Sure black soot and then POW ! out shot a glow plug stem bouncing off the splash guard. Wasn't one I left behind.

What's in your pre-chambers, CAMO
 
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mgFray

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This is how I do it. No fancy tool... just a good pair of Vise Grips. 10 mm socket gets it loose. If swollen a squirt of oil in the hole. Vise Grip locked on the 10mm glow plug head, tight not crushing. Pulling hard with a controlled feel and rotate 1/8 turn clockwise, then counter clockwise. Repeat as needed. The deal here is to draw and re-shape the split stem back thru the bore. Stay true to the bore as to not snap the tip completely off. Slow and easy as you go, oil as needed, watching progress, holding breath just right.
I'm not sure I'm "skilled" enough with a vise grips to do that for all 8 cylinders.. especially the ones on the right side under the CDR and all the hoses.. as well as the one behind the generator on the left side..

Story time... when I had all the injectors and plugs out...got the big idea💡 to blast air into the plug holes. Sure black soot and then POW ! out shot a glow plug stem bouncing off the splash guard. Wasn't one I left behind.

What's in your pre-chambers, CAMO
YIKES! This is the crap I'm worried about, as I know the previous owner(s) were not exactly 'meticulous' as I am about following the directions and not leaving parts behind.. But then again, I'm not ready to pull the injectors either, unless I have to. I will definitely use the advice of dripping a bit of oil into the hole before extracting them!
 

86humv

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Another Hmmwv mechanic told me about the 10mm plugs he found last week....I would guess..China plugs
 

Milcommoguy

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This is how I do it. No fancy tool... just a good pair of Vise Grips. 10 mm socket gets it loose. If swollen a squirt of oil in the hole. Vise Grip locked on the 10mm glow plug head, tight not crushing. Pulling hard with a controlled feel and rotate 1/8 turn clockwise, then counter clockwise. Repeat as needed. The deal here is to draw and re-shape the split stem back thru the bore. Stay true to the bore as to not snap the tip completely off. Slow and easy as you go, oil as needed, watching progress, holding breath just right.

I have pulled a bunch this way. When out, inspect to see if extra parts were left behind. Not sure or ??? No problem here too. A little more work to pull the injector (and lines) and fish the extra parts thru the big fat injector port. Next with a blast of air down the glow plug hole and crud coming out the injector port. Safety glasses a must. Bullet proof vest optional.

Story time... when I had all the injectors and plugs out...got the big idea💡 to blast air into the plug holes. Sure black soot and then POW ! out shot a glow plug stem bouncing off the splash guard. Wasn't one I left behind.

What's in your pre-chambers, CAMO
Where did I come up with 10mm ?? 3/8 is what the Swellman plugs are.

Got me again 86humv. CAMO
 

Retiredwarhorses

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Another Hmmwv mechanic told me about the 10mm plugs he found last week....I would guess..China plugs
That would be me, 2 M1165’s with non-working Gp’s, the plugs were purchased by the owner on eBay, they are 10mm heads and the body is chrome. They all metered from 3.5-4,5 ohm.
The plugs Have the part number and Mfg number stamped same as the OEM, but the plug appears to be chromed afterwards. There is a head stamp “746” on these Chicomm plugs not seen on true USGI plugs from Wellman, at least not on any of my current stock of 90 plugs. OEM plugs are more brushed nickel finish.
luckily, none of 16 were swollen…
 
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mgFray

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Got one out.. of course the tip is completely missing!
2A74B169-74A5-49E0-B2DE-217AFB918B89.jpeg
Glow plug has a 10mm hex. Says 746 on the head, and in the body 19207-12338771. MFG 3HCM3

guess I get to learn injectors now:mad:
 

mgFray

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We’ll make that 2. At this point I’m going to just expect them all to break, so I’m giving up for today. I guess this my project for tomorrow.
 

Action

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The only time i had swolen plugs, many years ago, I was able to get them out by slowly turning the swollen part through the threads. All stayed together.
 
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mgFray

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The only time i had swolen plugs, many years ago, I was able to get them out by slowly turning the swollen part through the threads. All stayed together.
Yup, I lubed them (WD-40), and VERY slowly pulled them out. (Had to use a split nut w/ shim, and then rotated the glow plug to pull it out.)
 

Retiredwarhorses

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Those tips aren’t broke off, they burned up and turned to dust, next up is to make sure your EESS does not have a bad
glow plug timer that won’t expire, as it will do the same to the new set as well.
The mfr code is Wellman, but the 10mm head tells me China knock offs.
 

mgFray

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Those tips aren’t broke off, they burned up and turned to dust, next up is to make sure your EESS does not have a bad
glow plug timer that won’t expire, as it will do the same to the new set as well.
The mfr code is Wellman, but the 10mm head tells me China knock offs.
Ya, my EESS is shot. I have a brand new Natron? unit, along with new TSN to install. But I'm not going to do that until I've got the glow plugs swapped out.

My plan is to pull an injector tomorrow, blow in compressed air and see if any bits of metal come out. Part of me is hoping that they are just turned to dust... but depending on how difficult it is to yank the injectors (one by one), it's probably worth doing at this point "just in case".
 

Milcommoguy

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Ya, my EESS is shot. I have a brand new Natron? unit, along with new TSN to install. But I'm not going to do that until I've got the glow plugs swapped out.

My plan is to pull an injector tomorrow, blow in compressed air and see if any bits of metal come out. Part of me is hoping that they are just turned to dust... but depending on how difficult it is to yank the injectors (one by one), it's probably worth doing at this point "just in case".

Good time to replace the return lines too. Once all this monkey motion is out of the way...should be good to go for a long time. Hose, clamps or the no clamp magic hose ??, anti seize and a few Bud's.

Keep an eye on the volt meter. Look for proper cycling sequence. Box not working and applying continuous glow / hard Amp load... big problem ahead. Shut it off and troubleshoot.

Fun with Humv..., CAMO
 
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mgFray

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Good time to replace the return lines too. Once all this monkey motion is out of the way...should be good to go for a long time. Hose, clamps or the no clamp magic hose ??, anti seize and a few Bud's.

Keep an eye on the volt meter. Look for proper cycling sequence. Box not working and applying continuous glow / hard Amp load... big problem ahead. Shut it off and troubleshoot.
Anything special on the lines, I don't have any spare parts at this point, but I'm not against buying some bulk lines from O'Reilly or NAPA and replacing them. As for clamps, all of the ones I've looked at (up to this point) do have the correct clamps on them. :)

Ya, I bought the new box, because I did some basic testing (according to the TM) and the wiring all checked out, but yet there doesn't seem to be any power to the glow plugs and the wait-to-start light no longer comes on. (It didn't when I bought the rig, then started to work for a week or so, and hasn't worked since.). The KDS box in there, when it DID work, did exactly what I expected. It stayed on for about 10 seconds turned off and I was able to start the HMMWV.
 
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