NHC250 oil leak - Steel Soldiers::Military Vehicles Supersite

M215 · 02-26-2008, 13:20

Hello SS
I've decided the time has come to fix an oil leak on the front of our M813, I'm tired of oil coating the inside of the engine area. I have assumed it was the front crank seal behind the harmonic balancer. Pulled the grill, radiator and harmonic balancer to get to the seal. Looking at the exposed front of the motor the seal may not be the source, the timing cover is covered with oil as well as the entire front of the motor. The leak appears to be near the bottom, not the heads or the oil pan, the fan blows so much air around it looks hard to pin point the source of the leak.

My question is there a common issue with these motors leaking oil that I maybe over looking?

I plan to replace the front crank seal, tighten all the oil cooler connections, replace the belts and lower radiator hose while access is easy.

Thanks in advance for any suggestions,
Karl

WillWagner · 02-26-2008, 21:34

Do the accessory drive seal too. It's the seal behind the pulley that drives the w/p and fan. Comming off is the easy part. Use a regular T bar puller. Going back on is the tough part IF you don't have the installer. Depending how it is built, there is a slinger washer or most likely, an "L" seal that seals the key way. You should also replace the wear sleeve on the pulley. BTW, you should have the puller/installer for the front seal too. If they have been in the cover a long time, the red sealant around the outside of the seal sticks real good to the bore in the cover, and they push into the cover a ways. If you dent the carrier, it deforms the seal lip. They are both teflon seals, not rubber. Very unforgiving when it comes to abuse when installing.

M215 · 02-27-2008, 16:49

Will,
Thanks for taking the time to respond!!

Pulled everything apart, looks like the seal behind the accessory drive may have been the leaker, lots of oil on the back side of the pulley. The drive flange for the harmonic balancer is pitted, so it will get a speedy sleeve.

Karl

Andydieselpower · 02-27-2008, 17:17

We found when putting on new belts on our M812 that the idler pully had bad bearings. You will notice a grease zerk on it but ours was obviously strictly ornamental for the previous maint. div. I can provide the bearing numbers if yours is bad.

Andy

joec · 02-27-2008, 20:35

Ahh new Juice maker i see. Hows the water pump?

WillWagner · 02-27-2008, 23:21

Karl, was there a little rubber, angled lookin piece in the keyway under the washer on the acc. drive shaft? Don't forget to put a new one in or it will leak as bad as b-4.