M998 Replacement Glowplugs

[DawGoneIt]

The M998 that we have down here at work runs well, but is hard starting. I just picked up Champion 191 CH238 glowplugs for replacements, anybody out there use these? Or someone out there recommend something else? Should anything else besides glowplugs be changed?

We are also going to put a block heater on the hummer as well. Any feedback appreciated.

 

[papakb]

With the availability of military glow plugs and their low price why would you choose to go with another brand?

I would advise a small amount of anti-sieze compound on the threads when you install them.

 

[DawGoneIt]

Got a source for some military GP's? I found out the plugs I bought were 12 v and wont work anyhow. I am located in S central washington on the columbia river. sounds like you've replaced these before.

 

[TedG]

EBay and search M998 glow plugs. you will find some military set of 8 for a reasonable price. I am not the seller...

 

[DawGoneIt]

will do. thanks for the replies fellas.

 

[DawGoneIt]

One more question for you guys....do you recommend buying a GP removal tool to remove hummer glow plugs?

 

[BLK HMMWV]

You may or may not need the tool. If the ends of the plugs have swelled then you stand a chance of needing the tool. If you have non swelling glow plug's in it now then there is a good chance you won't need it.
I would also suggest using some hi temp anti sieze on them when you put in the new ones.
I'll bet you won't need the block heater if you get your glow plug's replaced. Are you sure it's not a bad Glow plug controller?

A Hummer and a M998 are two different vehicles . Which do you have?
The M998 is a HMMWV or Humvee .
The other thing made by GM with all the chrome on it is a Hummer.
One is 12 volt 's the other 24 volts
Why people call HMMWV's Hummers I'll never know.

 

[DawGoneIt]

My bad...it is a 1987 M998 HMMWV, the real deal. From this day hence I will refrain from calling it a hummer! I will look at the TM and this forum for testing a bad GP controller. I posted a shot of it after it just got done pulling a crippled M1008 Chevy up a 22% grade with 3 hairpin turns.

 

[Augi]

AM General called it a hummer when they pitched it to the army. There are brochures and other documents around with hummer all over them.

 

[papakb]

There's really not a much better way to test the PCB/GPC than substitution. Your WAIT light and voltmeter tell you what the system is doing so get used to "normal" and then observe what changed. The WAIT light should come on for around 10 seconds and then begin cycling on a cold engine, when it cycles the voltmeter will drop into the yellow zone. this may continue for a short time after the engine starts as it warms up. After the engine is warm, the WAIT light may flash as the ignition is turned on but then go out and the engine will start.

All of this depends on the Protective Control Box and Glow Plug Controller you have in your HMWWV. The early Prestolite boxes and those up to the KDS yello label box needed the GlowPlug Controller on the water crossover pipe. After that, the green label KDS boxes and the S3 boxes no longer need the GPC. You can leave it in place, the pin is dead to the PCB.

The swollen glow plug removal tool is invaluable when and if you need it. The other option is to break off the glow plug and then try to fish it out thru the injector hole or pray that it blows out the exhaust.

Kurt

 

[DSO_351]

Wellman was the original manufacturer. AC Delco AC15G may work.

 

[DawGoneIt]

@Papakb: the cycling seems as you describe when starting the vehicle. I have a battery powered test light to see if the glow plugs still have life in them (do this before considering GPC replacement). How spendy are the green label KDS boxes (and the S3 box)? Maybe it would be a good idea to replace the PCB? Do people look for trades in a different forum on this site?

@DSO 351: Can you get those AC Delcos through an auto parts store? Do you have to modify the plug tip? Ever use them?

 

[BLK HMMWV]

Ebay is a source for HMMWV parts. Like Glow plugs.
Do a search under M998 for example.
If you don't like Ebay You could always try Kascar but you will pay more.
You may also try The Hummer Parts Guy.
He is in most cases cheaper then Kascar and your order will be drop shipped to you straight from AMG free shipping.

As to the GPC unit drop a PM to 86Humvee hear on the board I believe he has a buch of controllers maybe not the green label ones .

BH

 

[bfdvollie]

Our hmmwv has become hard to start. We are going to use the pinpoit tests to see if it's the module.

 

[fllaw1]

"To Change or not to Change that is the question"

Bgrnd: 92 M998 40K Miles with fairly new 6.5L

Glow plugs appear to be the "US Army Tank Automotive Command" #12338771
SMEs help me out is this normal wear, fairly new or been in a while? Has anyone actually used the Delco AC15G or the Autolite 1108 (Oreilly auto) as a replacement?

 

[1 Patriot-of-many]

Test the ones i you have in your engine. Very easy. except for your back. Use an ohm meter, I believe it should read .5 -5 ohms. I had the AC delco's 15G put in my 6.2 early in the year. They are supposedly self regulating. Even with a bad box through the year, I just put a new box in after testing them. They all were 3.2-3.3 ohms.

 

[fllaw1]

Test the ones i you have in your engine. Very easy. except for your back. Use an ohm meter, I believe it should read .5 -5 ohms. I had the AC delco's 15G put in my 6.2 early in the year. They are supposedly self regulating. Even with a bad box through the year, I just put a new box in after testing them. They all were 3.2-3.3 ohms.

Thanks