Truckoholic
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- Colorado Springs, CO
So I just today finally bought me another M925A1 after a three year hiatus of not owning any military vehicles. I bought a house and property here in northwestern Oregon a year and a half ago, and there was no extra money or time to be messing around with military trucks for a while. ha haBut here lately I'd been dying to get my hands on another M925, so I started scanning craigslist, and the auction sites, and finally came across one for a good price not too far from me. Went and looked at it, and ran it a little today, and decided I definitely wanted it for the price asked.
It is a 1987 M925A1 that was rebuilt in 2005 and has 2,300 miles showing on the odometer. So it's in really good shape. Has ABS and the spare tire rack and crane together with new spare tire which I was happy to see. It has really nice 14.00-R20 tires on it. The guy I bought it from, bought it 3 years ago to turn it into a water truck, had it hauled from the base to his house, and there it sat ever since. Well, he's moved it around his yard now and then, but when he discovered the water in the oil, he didn't run it much anymore, and then after a while decided to sell it.
So, the water in the oil doesn't concern me so much on that particular engine. I have read multiple threads here in the forums using the almighty "search" feature, and have learned a lot about the usual culprits such as the oil cooler, and cylinder liners, and freeze plugs in the heads. While I was there looking at the truck, I pulled the oil cooler off to look at it, and it did look quite corroded and very clearly a possible suspect. But I covered one of the oil passages and blew into the other one, and could not detect any air escaping through the water passages. But the reason I highly suspect that that probably is where the problem is, is because when I took one of the coolant lines off specifically to see where the water level in the engine was, to get an idea of where the problem is, the water level happened to be right at the level of the bottom of the oil cooler. So I'm pretty sure I can rule out freeze plugs in the heads, or cracked heads or head gaskets. The water level was right smack, level with the lower part of the oil cooler. Which would make perfect sense if there is a hole in it, and the truck sat there slowly leaking water into the oil pan through that hole. And over years, of the truck sitting there, it could have leaked through a hole that I couldn't detect by blowing on it.
But what sucks is....I also realized that the oil cooler sits at about the same level as the cylinder liners do. So if there is a hole in a cylinder liner, or bad cylinder liner o-ring, I am guessing the water would have been about the same level. I'm trying to look through the TM's for that engine to see if there is an exploded view of the engine, that shows the water passages, so I can verify that the water level would be at the same spot whether it was a cylinder liner, or the oil cooler that was bad. I'm having the truck hauled home, since I don't know yet where the water is coming from. I am tempted to bring new oil, and changing the oil where the truck sits, and put more water in and drive it the 180 miles home, and hope it is just a small enough leak that it would make it home fine, but I don't want to take that risk, and want to just have it hauled home and take the oil pan off, pressurize the cooling system, and see where the water is really coming from.
Had I been able to verify that the oil cooler did indeed have a hole in it, I most definitely would have just ordered a new oil cooler core, and taken that, together with what I needed to change the oil, and gone up there, and changed out the core, changed the oil, added water, and would have driven the truck home with no worries. But since I was not able to tell by my blow test, that the oil cooler core was indeed the culprit, I figure it's safest to spend the thousand dollars to have the thing hauled to my shop.
But do any of you happen to know what page, or have a picture, or have any independent knowledge yourselves as to whether the water level in the engine would indeed be at the same level whether it was a hole in the oil cooler core, or a cylinder liner problem? Looking at the outside of the engine, it appears the cylinder liners and the oil cooler are about the same level, but I've never had the liners out of an NHC250 before, so I don't know exactly what level on the engine the water jacket is, in relation to the oil cooler.
Anyway......... I've very excited to finally have another military truck! This will be the 5th one I've owned, but the first one purchased from a private party and not through GL. Yet at a GL price. haha. I've got a turbo, and exhaust manifold off a 350 cummins I've been holding onto for years now. I intended to put it on my last M925A1, but never got around to it. So after I get the water in oil thing figured out, that's one of the first things I plan to do to this truck. Put the turbo on it, and then straight pipe it. The paint is nice enough that I don't think I'll feel a need to sandblast it and repaint it like I did all of my other ones. And this one I plan to actually keep this time. That's what I said about my last one, but that didn't last long. ha ha. They are just way too easy to sell for a profit after they are all fixed up nice. So I think the key to keeping it, is to just not fix it all up nice.
Went up to where the truck sits today to change the oil, and see if I could make the thing road worthy enough to drive it home. When I took the oil drain plug out, I found only the normal tiny bit of metal substance stuck to it like you would find on any good condition diesel engine, so I was quite happy about that... But after the oil drained out, I decided to stick my finger in the drain hole and feel around, and to my horror, I felt multiple large chunks of cylinder liner, together with multiple cut up chunks of cylinder liner o-ring. DAGNABBIT!!!!! What do you guys suppose the chances are of the liner being destroyed to that extent and the block still being good? I'm betting slim, with that connecting rod and piston bashing around in there, and who knows how long it was run like that. But, I'm having it hauled to my place, and will drop the pan, and look up in there and asses the damage.
