1998 G320 - Belt jumped off

[joef]

Go figure, finally get the audio sorted out last night in my wifes g320. I take it to run one of the kids around and I get the dash flashing a battery issue followed by no power steering and overheating. I found the belt not where it should be
Its on its way to my mechanics right now and I'm trying to be proactive incase their is something that needs to be ordered - a tensioner perhaps
There may be some issues with looking up parts since 1998 G320's were not imported into Canada. In case a tensioner is needed could someone please post the part number for me.
Any info would be appreciated.

 

[gerryvz]

A 1998 G320 would be the second year of the M112 V-6 engine in the G-class, not the M104 that I have. However, I have seen some 1997 and even 1998 models (at least, billed as such) but with M104 engines. 1997 was sort of a transition year for "rest of world" trucks. So, which engine does your truck have? V-6 or inline-six? I'd think the M112 V-6, but just making sure.

If you have the V-6, then your belt tensioner should be 112 200 09 70, but you should definitely double-check this part number to make sure. It should be the same tensioner that is used with the MLs, E320s, etc.

Fairly common part that just about any "stealership" should have.....

 

[joef]

Thanks for the reply Gerry. Its a m112. I figure it should be common part, but just wanted to make sure.
I have my old daily driver, an ml320 which I waiting to be pillaged, so I may have a backup plan - fingers crossed!

 

[gerryvz]

Just so I can be sure, what are the first 9 characters of your VIN/chassis number? Should be something along the lines of "WDB4632XX"

That will allow me to triangulate it "for sure"

Mine is WDB463231, (indicating a G320 with M104) but the last two digits on yours should be higher than mine.

 

[Klink]

Unless the tensioner has been replaced in the last five years or hundred thousand miles, it should be replaced for good measure no matter what its condition appears to be. Make sure that the small rectangular cover on the oil filter housing, as well as any of the oil cooler and/or housing seals (if your engine is so equipped) are not leaking. If any of these are leaking the oil tends to drip straight down and infiltrate the belt tensioner, eventually disintegrating the friction damper plates inside of it. The resulting excessive belt oscillation will cause problems. If you have one of the rare M112 engines fitted with a telescopic belt damper, replace it at the same time you replace the tensioner. These dampers are functionally identical to the ones already known to most of us from the M103/M104/etc. Also replace the uppermost guide pulley for the belt. It is the most common source of belt woes on the M112/113. I don't have a computer awake to give you a part number on that one right now. When replacing that pulley, also replace its plastic dust cover. They are frequently omitted for no good reason, allowing the engine fan to constantly assault it with dirt, and occasionally moisture. Except for the tensioner itself, which still isn't too bad, none of these parts are expensive, and they are all easy to change.

Take care whatever work you may do on this motor to blow out any bolt holes, and lubricate the bolt threads with a light oil. Most of the fastener bores on this and newer engines are un-threaded as cast and are fitted with self tapping bolts when it is assembled. These bores have channels that catch and contain the shavings that occur as the threads are cut. Once you remove a bolt, this debris gets displaced into the working threads, and you can find yourself with cross threading and seizing fasteners upon reassembly.

A little safety note: These and later engines are assembled by robots. Nothing has rounded edges, or gets de-burred during manufacture. Expect scalpel sharp edges on every component that you handle, including the block itself. Actually, most especially the block and cylinder head castings!

 

[joef]

Just so I can be sure, what are the first 9 characters of your VIN/chassis number? Should be something along the lines of "WDB4632XX"

That will allow me to triangulate it "for sure"

Mine is WDB463231, (indicating a G320 with M104) but the last two digits on yours should be higher than mine.

I'm 463233.

 

[joef]

So it turns out one of the pulley's had a faulty bearing. I didn't get all the details from the mechanic. I could only pop in quickly Saturday morning on route from an appointment. He showed me the part, and was missing all but 4 of the metal balls that occupy the bearing.
He had it up and going by noon saturday.
The shame of it all, the m112 engine is quite close to the rad/fan. Made for very tight quarters for getting at what needed to be got to. More so since there is 10" spare at the back of the engine to the firewall.

 

[gerryvz]

Thanks for the resolution. I wonder if it was the upper guide pulley that Klink mentioned.

 

[jaymanek]

I chose to do the water pump on my G500 M113 engine recently... NOT FUN.
Especially since the first time I must have not seated the bottom hose to the water pump correctly which resulted in a slow leak... so I had to strip it all again a week later to be able to get to the hose clip to replace the hose.

No room at all and the missing skin from my hands proves it!

Much easier working on our M119's... although I cant say the water pump on that was particularly easy either.