3116 timing housing leak

[hugo_koss]

Hey guys, I'm looking at getting 1998 M1078 with 20,000 miles on it. The only problem the owner identified is a timing housing leak. He said it's coming from the timing housing cover and when ran for about an hour it lost about a shot-glass of oil. I was debating on driving it for 200 miles, but now I'm worried that might be more than just a bad gasket. Has anyone dealt with the same issue? Thank you

 

[ramdough]

I would figure out where it leaks….. they are known to crack if the air compressor is not bolted secured. That can lead to more damage.


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[Third From Texas]

I would NOT drive it w/o repair

One of the very first M1078 recovery videos I watched was where I guy tried to nurse one home with a cracked cover and destroyed his engine. They discovered the crack, repaired it, but did not notice the nut inside had backed off the shaft. Things grenaded,

As Ronmar said, pretty common crack/failure there when the compressor bracket comes lose.

 

[GeneralDisorder]

One of the many benefits of the later trucks was the realization that the excessive driveshaft angles and speeds caused vibration and problems with fasteners all over the engine coming loose. Alternator bolts back out, the bracket for the air compressor and power steering hydraulic pump will back out, the starters can come loose. This is a sign of a deeper problem of the driveshafts possibly being out of balance compounded by the high angles and speeds and the lack of Nord Lock washers. Later trucks added Nord Locks to almost everything on the engine and eventually they eliminated the high driveline angle on the LMTV's rear shaft.

Also the Army likes CAT engines over other options and one of the reasons they like them is they don't typically leak. So a leak is usually not a simple gasket problem

I know it probably seems like a good deal and cheap but if you are going to buy that truck you should tow it and just assume it has a cracked timing cover or worse. And if that hasn't been addressed then likely the driveshafts haven't been balanced, the oil line of death hasn't been addressed, and probably a TON of other stuff. Many of these early trucks are approaching 30 years old at this point. Anything can and probably will happen trying to drive something that old with problems and neglect and probably relatively low mileage. The difference is that these are expensive to recover if you break down and you might cause more damage that could also be hugely expensive to fix.

 

[Ronmar]

The bracket in question is #17 in this pic. Missing, broken or loose, you probably have a timing case crack. People have welded the case cracks in place, but the support bracket needs re-installed properly at any rate…

 

[Awesomeness]

More info about the air compressor bracket, with references to previous threads and stuff, in the document here in my signature. Lots of other distilled info too.