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Discussion Starter #1 (Edited)
Howdy,

Bought a 2000 GMC 3500 Dually CC 4WD with 122k miles. Diagnosed leaking injectors, ordered the PCM, Turbo-Master, Bosch Standard Injectors from Heath. In order to get the truck started in cold weather, replaced the driver side glow plugs tonight (god willing she will start and I can get her to a nice warm shop on Saturday to do the rest of the work). 3 of the 4 glow plugs tested at 500k + kiloOhms (bad), so I think I may stand a chance. That being said, I inspected the old glow plugs and have one (it tested bad) that is not like the others. Pics are posted... you can see a nice carbon buildup that is caked on. This would indicate to me, in a gasoline engine, that I have oil getting into the cylinder. Any thoughts? The rest weren't pretty, but any carbon wiped right off. This is definitely caked.

Thanks for your expertise guys!

Josh
 

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Welcome to the Forum!

I replaced my glow plugs recently. My old ones look like yours.

What brand/type did you replace them with?
 

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Discussion Starter #3
The replacements are AC Delco 60G's. The ones I pulled out were Autolite 1110's. The pics are of two old ones... the left in the pic is the only one that had significant carbon buildup on the "shoulder" portion... the rest were relatively clean. Could be the carbony one was just older than the rest I suppose.
 

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IMHO, some carbon build up is normal and nothing to worry about.

When you replace the rest of them put some anti seize on the threads and make sure they are torqued to 17 ft/lbs
 

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Also, go to the UserCP in the upper right corner of the Forum page. Click on Edit Signature and put some info about your truck there. It will show up each time you post.
 

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Discussion Starter #7
Quick update: Truck started with some hesitation at -5 F, so that's a good sign. Thanks guys for your input. I will update if it turns out there is a bad cylinder... seems like a reasonable check if buying a new truck. This one blows no smoke, but if it has a bad ring/valve, reading the plugs might be worth it if in the market.
 

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You should be looking at the tip, not the spade end.
 

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Chances are the injector return hoses are leaking.

That causes the crudz on the upper thread.

IMO, there are 2 GP for this truck, the Bosch Duraterm and ACDelco 60G.

Other brand including older ACDelco are not recommended.
 
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Chances are the injector return hoses are leaking.

That causes the crudz on the upper thread.

IMO, there are 2 GP for this truck, the Bosch Duraterm and ACDelco 60G.

Other brand including older ACDelco are not recommended.
And both of those typically require manual over-ride to be most effective.
I'll stick to my OEM 9gs and PCM control, so my wife or daughter or anyone else can drive my truck without first reading a modified owners manual. LOL
 

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I don't have override with the Bosch and they are fine and they don't swell like the 9G does. I drove it up north and they are fine also.

Assuming 9G is still made, well they probably do with bad quality aftermarket copycats.

They have studied the Duraterm and it does not need override like 60G does.
Well, unless you live in Alaska but nothing works over there too well anyway for this truck.

The override was created actually for the 9G before there were even Duraterm or 60G. Until the 9G started swelling, then 60G was made as improvement to 9G that is until Duraterm became known among 6.5 crowd sold by Heath, initially.

If you don't believe me, you can search old threads by TurbineDoc, GMCTD, TexasDieselGuy, Jifaire, Knkreb, etc. The nice thing about this forum is that the search is working great unlike the Toyota forum.
 

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JMJNet; The override was created actually for the 9G before there were even Duraterm or 60G. Until the 9G started swelling said:
Fwiw my 97 came with 11Gs ,which I,.ve always presumed were the successor to the 9G,s . Always some ambiguity as to whether the 11,s had the swelling problems of the 9G,s . Just some more useful or otherwise historical info.
 

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One on the left looks like it was not seated in the head. Notice the taper on the bottom should be clean where it seats in the head. Carbon has been blown past the seat.

Ohm test is not a reliable test. Only way to test them is out of the head and 12volts applied. Tip should get red instantly. I have seen quite a lot of glowplugs ohm fine but get red in the middle first before heating the tip. Keep in mind the tip is what really gets the fuel burning because that is what protrudes into the combustion area.
 

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I don't have override with the Bosch and they are fine and they don't swell like the 9G does. I drove it up north and they are fine also.

Assuming 9G is still made, well they probably do with bad quality aftermarket copycats.

They have studied the Duraterm and it does not need override like 60G does.
Well, unless you live in Alaska but nothing works over there too well anyway for this truck.

The override was created actually for the 9G before there were even Duraterm or 60G. Until the 9G started swelling, then 60G was made as improvement to 9G that is until Duraterm became known among 6.5 crowd sold by Heath, initially.

If you don't believe me, you can search old threads by TurbineDoc, GMCTD, TexasDieselGuy, Jifaire, Knkreb, etc. The nice thing about this forum is that the search is working great unlike the Toyota forum.
Yep, the Duraterm is nice and toasty at 12 sec's, which is what the stock controller's do. A few more seconds would be nice if its stupid cold but they'll start my witch's brews. :hehe:
 

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I don't have override with the Bosch and they are fine and they don't swell like the 9G does. I drove it up north and they are fine also.

Assuming 9G is still made, well they probably do with bad quality aftermarket copycats.

They have studied the Duraterm and it does not need override like 60G does.
Well, unless you live in Alaska but nothing works over there too well anyway for this truck.

The override was created actually for the 9G before there were even Duraterm or 60G. Until the 9G started swelling, then 60G was made as improvement to 9G that is until Duraterm became known among 6.5 crowd sold by Heath, initially.

If you don't believe me, you can search old threads by TurbineDoc, GMCTD, TexasDieselGuy, Jifaire, Knkreb, etc. The nice thing about this forum is that the search is working great unlike the Toyota forum.
A match stick would likely initiate the combustion process of a healthy 6.5 diesel engine in texas.. I recall one family trip to florida where my fuel heater disabled my GPs, truck still started with little effort down there but back home in Kansas, not so easy.. Good thing I ordered a new FFM from our hotel in Orlando and it was in ass'hole'aria POBox as soon as redeye got home..
My truck has been all over the lower and upper 48. Been up and down the appalachians often dragging a 5+ ton trailer with it in all kinds of adverse winter conditions. Ive been stuck in several blizzards with ambient temps well below 0°F daytime dropping to -20°F after sunset. Cant recall any time it didnt fire up, even when inadvertantly left unplugged in negative digits, she may not have liked it much but fired up she did as she always has. NEVER HAS COLD WEATHER BEEN A PROBLEM FOR MY PRECIOUS, guess Im just one lucky SOB..
Hell, its been near 0°F here most of the week yet after sitting for 8-10 hours in the fully exposed parking lot at work all day, block heater unplugged, fires within couple revs. Plugged in overnight, fires up INSTANTLY.. Been like that for 20 years, should I go buy a lottery ticket in the mornin'..
Now that I think 'bout it, never had a 9g glowplug fail (KNOCK ON WOOD) but then again, I dont try to over-ride the system. Usually when it hasnt started within the first 5 second, I know theres something wrong and although I may try again and go, I'll make it a point to figure out WTF the problem is sooner rather than later, BEFORE eventually burning down the starter or damaging the gp system by repeated attempts to make it go..

Since were dropping names, you forgot IamDave and RCpuller.. Those two guys used to give me the hardest time for questioning them and those experts whom we now know were mistaken in regards to how a 1995 model work. I suspect thats why "GM-Diesel(dot)com is being rebuilt" for the past 3 or more years now. That site as this one and many others are, was full of misinformation, much of it originated from those on your list. I want to thank them all for the inspiration that continues to drive me to get thoroughly educated and PROPERLY TRAINED to work on my own POS and when necessary correct them and others before (hopefully) it results in another costly misdiagnosis.

I believe you, only Im not that lucky bud nor is my truck as special as all those experts who kept insisting it was way back when. And of course I was the ******* for insisting they were mistaken back then too only I didnt have the education or the indisputeable PROOF as I do now in order to show them they were simply mistaken so I resorted to lurking 'round here for several years while I got the FSMs as suggested by IamDave because the HAYNES and CHILTON manuals I bought were full of inaccurate info in regards to troubleshooting 6.5. Often wonder how many people were lead a stray by those worthless pubs...

No hard feelings I hope.. I come here to help others avoid getting bent over and/or making costly mistakes and yes, sometimes I even learn a new thing or two in the process.
Im not here to help folks spend money on questionable upgrades, Im here to help folks avoid throwing it away entertaining anuttier MSDiagnosis.


NEED MO" PMD(cowbell) LOL
 

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^^^^ I'm lost, what are you criticizing?
 

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Bosch Duraterms, hands down. They turned my truck from a nightmare in the winter to a breeze. I started mine in -25c a few winters ago with the new Bosch plugs, and that was with stock glow times.

And I agree, the often referred to ohm test has proven unreliable. I have 3 glowplugs in my garage on the shelf that passed the ohm test but when tested only the very end of the tip glowed faintly after 20 seconds as opposed to the new plugs that glowed almost their entire length after only 6-10.
 

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Yep, the Duraterm is nice and toasty at 12 sec's, which is what the stock controller's do. A few more seconds would be nice if its stupid cold but they'll start my witch's brews. :hehe:
"12 sec's, which is what the stock controllers do" at what ambient temp?

Must be living in Salem then, puts your ambient temps near 0°F for that long of a preglow.
see DS4 pg 69



^^^^ I'm lost, what are you criticizing?
Not so much criticizing, just rambling mostly. Tired, been up for nearly 48 hours dogsitting. ***** just got snip'd and tummy tacked, she's not too happy.







Bosch Duraterms, hands down. They turned my truck from a nightmare in the winter to a breeze. I started mine in -25c a few winters ago with the new Bosch plugs, and that was with stock glow times.

And I agree, the often referred to ohm test has proven unreliable. I have 3 glowplugs in my garage on the shelf that passed the ohm test but when tested only the very end of the tip glowed faintly after 20 seconds as opposed to the new plugs that glowed almost their entire length after only 6-10.
So you had 3 dead plugs, replaced them all with duraterms and it was like night and day?
 

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"
So you had 3 dead plugs, replaced them all with duraterms and it was like night and day?
No, I had 3 partially working plugs and 5 completely dead ones. Don't read too much into things.
 
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