My C12 Cat has a rubber/foam kinda thing that's wrapped around the oil pan. It's bolted on somehow, (I haven't really looked yet), but it's a 1" thick molded piece, not something that's sprayed on like undercoating.

I'm wondering what the purpose of this thing is and if I can remove it. Somewhere around the oil pan I have an oil leak, (might be the front seal, might be the oil pan gasket), but I can't tell where it's coming from because this wrapper hides the whole oil pan.

It must keep a LOT of heat trapped in the oil pan because when the motor is hot, the oil level 'grows' by 2 or 3 quarts. It goes back down when it cools off, but I've never had a motor like this thing before.

I've said it before and I'll say it again... with this Cat I don't need a mechanic, I need a vet!

 

That is a noise barrier, it will degrade and fall apart. I am, surprised that it has not already started to come off in chunks. It goes up the side of the block also. You should be able to remove the lower half to inspect for oil leaks, I'm betting on the front cover leaking oil.

 

So I assume I can just remove the whole thing with no negative mechanical effects?

Thanks Tim! As always, I appreciate your answer.

I don't remember if I told you or not, but I *think* the fuel in the oil problem has been resolved. We replaced the injector seals and it seems to be ok now. $113 for 18 tiny Rubber O-rings. Surprisingly simple to do, just a lot of part removing and replacing.

I've been carefully monitoring the oil level ever since and have noticed that the oil level will grow substantially when the oil/engine is hot. On the stick it will show the equivalent of an extra 2 quarts when hot, then return to normal when it completely cools down. I've never had anything do that before. I guess it's the 'Cat Learning Curve'!

 

I have pulled the barrier off when it starts to fall apart, you will notice some extra engine noise but no big deal. I should have also told you it is also a heat barrier, Cat likes them to run hot for emission purposes.

Glad you got the oil fuel dilution solved.

 

Thanks Tim. Yeah, I'm happy the problem appears to be solved as well. Now if I can just wrap my mind around the oil growing and shrinking as much as it does I'll be doing good. Maybe that rubber wrap keeps in a LOT of heat.

 

My C12 "had" the same on it........

 

Is it noticeably louder in the cab now?

 

Honestly, I didn't notice any difference at all.

 

I think I'm gonna yank it off of there then. Thanks!

 

Front gear housing like to leak on C10/12's. The bolts come loose, sometimes go thru the gear train. There is an updated, stronger bolts and higher torque. Also the oil dipstick tube can go in 4 different places on those engines. So the 3 other holes, have a rubber plug installed. They kinda look like a 45gallon drup, but its about 3/4" tall or so. Bet our shop had couple of those engines apart each month for yrs. Then seem to kinda disapper, then boom, 2 in this week for overhauls.

 

Thanks! I haven't had a chance to clean it all up and see what's leaking yet. I got the rubber cover off and that will make it easier tho. Now I've found I have an air fitting leaking on the top of the tranny. Not a big deal to fix except I have to find a way to get my fat butt up in there to replace it!

 

If its toward the middle of the tranny pull the shift tower boot.

 

It's not. It's on the right side towards the bell housing. Almost to the side but not close enough to be able to see it when you look up from the bottom of the frame rail. If I had a pit I might be able to wiggle up between the back of the tranny and the next rearward crossmember, between the drive shaft and frame rail and reach forward, but laying under the truck I just don't bend that way anymore!

 

Can not notice any difference,