Engine/Transmission (1994 - 1998) oil leak, long and frustrated!!

[BIG C]

Need some help with my oil leak. I have 2 leaks, one coming from the rear of the oil pan and bellhousing adapter. The other is coming from the front driver side of the motor. If I clean everything of and start it up and idle there is NO leak. If I rev it a little to build up some oil pressure the rear of the oil pan starts to leak a little. The front stays dry. If I go for a drive the rear leaks bad and the front is leaking to. The problem is now it is blown all over and I cant tell where it is coming from. The front looks like its comng from the front cover. The rear is definatly coming from the back of the oil pan where it seals to the block. I have replaced this seal twice now and it still leaks in the same spot. Again not at idle but after a drive. Im at a loss and getting frustrated. What should I do. I dont want to drop the transmission again just to have it leak again. Maybe the pan is warped? Could something be pressurizing the oil pan? The blow by tube is dry. The rear main seal is dry. The valve covers are dry in the back. The KDP has been tabbed. The vacuum pump to gear housing is dry however the steering box, trac bar, and hole front end on that side is slobbered with oil. I give up. Maybe its time to take it in to the shop?



Thanks,

Chad

 

[Extreme1]

Could the front leak be coming from the seal at the power steering pump/vacuum pump? Have you replaced the pan gasket? When you did the seal did you pull the housing or leave it on and pull the seal out of it?

 

[WDimig]

be sure to check the tappet cover gasket, mine is leaking right now, and it almost looks like it's coming from the pan, but it's not. could also be the rear crank seal leaking, if you have an auto, take the bottom transmission bell housing cover off, and look up there and see if you see any oil. if its good, look at the tappet cover gasket, or the oil pan. the front oil leak could be from a front seal, possible KDP damage on the gear housing it'self. hard to tell without getting a a good look at the engine. good luck.



wes



edit: you mentioned that the blow by tube it dry?? you should have a slight amount of oily residue on the inside of the tube. with the engine running, check the tube to see if you can feel any blow by coming out of the tube, if not your tube may be somehow clogged up, and creating excessive crankcase pressure. that would lead to a oil leak eventually.

 

[BIG C]

Ill answer the suggestions in the order received..... the ps and vac pump are clean, no leaks here. Ive replaced the oil pan gasket twice. Ive never replaced the rear main seal, its dry as a bone. The seal I replaced was the oil pan gasket/seal.



The tappet cover might be a possibility since I havent checked it yet. Rear crank seal is dry. The KDP is tabbed. Blow by tube... ... there might be a bit of oil coming from the tube but not nearly what accumulates on the ground when I shut it down. I cant really tell if there is any air coming from the tube. I put my thumb over it and nothing happens even when I release it I dont hear or feel anything. I thought it might be plugged too so with the engine off I blew into the tube and didnt feel any pressure or resistance. If it was plugged I would think I would feel some resistance.



Im almost positive its the very rear of the oil pan gasket. After a drive with the motor still running I can wipe the bottom of the bell housing adapter and I can see oil from both sides of the oil pan come running down the sides of the bell housing adpater. This would indicate that its not the tappet cover since both sides are leaking. The part that pisses me off is Ive replaced that oil pan gasket twice and it still leaks in the same spot. Thats why Im starting to think the oil pan is warped or bent. Any other suggestions??

 

[Joe G.]

I've had a leak like that a few times. Each time it was #5 or #6 valve cover gasket. The oil runs down both sides to the bottom rear corners of the engine.

 

[WDimig]

Ill answer the suggestions in the order received..... the ps and vac pump are clean, no leaks here. Ive replaced the oil pan gasket twice. Ive never replaced the rear main seal, its dry as a bone. The seal I replaced was the oil pan gasket/seal.



The tappet cover might be a possibility since I havent checked it yet. Rear crank seal is dry. The KDP is tabbed. Blow by tube... ... there might be a bit of oil coming from the tube but not nearly what accumulates on the ground when I shut it down. I cant really tell if there is any air coming from the tube. I put my thumb over it and nothing happens even when I release it I dont hear or feel anything. I thought it might be plugged too so with the engine off I blew into the tube and didnt feel any pressure or resistance. If it was plugged I would think I would feel some resistance.



Im almost positive its the very rear of the oil pan gasket. After a drive with the motor still running I can wipe the bottom of the bell housing adapter and I can see oil from both sides of the oil pan come running down the sides of the bell housing adpater. This would indicate that its not the tappet cover since both sides are leaking. The part that pisses me off is Ive replaced that oil pan gasket twice and it still leaks in the same spot. Thats why Im starting to think the oil pan is warped or bent. Any other suggestions??

in that case you should check your valve cover gaskets, especially #5&#6

ive had times wheere the #6 was leaking and you couldnt really see it, and thought it to had been the tappet cover, but there was oil on both sides of the engine. probably wouldnt hurt to replace all 6 gaskets, they are cheap. and it would eliminate a possible cause of the problem.



wes

 

[JGK]

I'm not familiar with the rear leak, but there's one that occurs in the front more often than it should. It shows up just above the oil pan on the left side of the block. The gasket between the gear case and the block leaks there. It's a bit if trick to spot it. Use a good flashlight. Clean real well with degreaser and wash it off and let it dry. Then drive down the street a block or so and back. You should see it weeping by then.



Sometimes it can be fixed (for a while) by tightening the gear case bolts (those you can get to) by removing the cover. If not, its time to remove the case. That's a major chore. Done that one already!



-Jay

 

[BIG C]

The more I think about it Im hoping its the valve covers. I checked them awhile back(before I changed the first oil pan gasket) and they seemed OK. Ill do some more investigating tonight after work.



Can I get these valve cover gaskets at a regualr auto parts store like NAPA or Autozone??



Thanks!

Chad

 

[Clinton]

Could the front leak be your oil pressure sending unit? Located just below the injection pump and behind the power steering pump. That would put oil right in the neighborhood you describe. They are known to fail and give erratic readings on the guage before they start leaking.

 

[BIG C]

Update

Looks like the leak in the rear was the #6 valve cover. I must have been a little careless and in a hurry the last time I retorqued the head studs. The stud on the #6 rocker was not seated all the way and the valve cover was hitting it and not creating a good seal to the head.



Thanks Guys!!



Chad

 

[Joe G.]

Don't feel bad. I've done that a few times. Now after I THINK I have it right, I get out a little extension mirror and double check it.

 

[trucknut]

Timing pin

Check the timing pin below the inline pump - is a little devil to check but has been known to leak.

 

[CumminsPower98]

Vacuum pump to gear case is where I have had the most trouble on mine and others. I have since gone to no gasket and a thin bead of RTV only and so far it's great.

 

[JPittinger]

I'm not familiar with the rear leak, but there's one that occurs in the front more often than it should. It shows up just above the oil pan on the left side of the block. The gasket between the gear case and the block leaks there. It's a bit if trick to spot it. Use a good flashlight. Clean real well with degreaser and wash it off and let it dry. Then drive down the street a block or so and back. You should see it weeping by then.



Sometimes it can be fixed (for a while) by tightening the gear case bolts (those you can get to) by removing the cover. If not, its time to remove the case. That's a major chore. Done that one already!



-Jay

Hey Jay- This is exactly where mine is leaking. I was gonna try to tighten the bolts first, but if it doesn't work... Is there any possibility that a new gasket could be slipped between the case and the block??? After studying my service manual I still can't tell. Maybe I'm grabbing at straws, but I really don't want to pull the cam... Thanks, JJ

 

[GAmes]

Hey Jay- This is exactly where mine is leaking. I was gonna try to tighten the bolts first, but if it doesn't work... Is there any possibility that a new gasket could be slipped between the case and the block??? After studying my service manual I still can't tell. Maybe I'm grabbing at straws, but I really don't want to pull the cam... Thanks, JJ

I have also replaced that gasket. The simple answer is no. But before you do a major engine teardown, check to see if the rear mounting brace for the injector pump still has it's mounting bolt. When my injector pump was removed we found the bolt mssing. My theory is the weight of the pump hanging on the front mounting bolts warped the case enough to allow the gasket to leak. I know for a fact that the mounting bolt missing from the vac pump/power steer pump bracket caused that gasket to leak.

 

[bmoeller]

I've had a leak like that a few times. Each time it was #5 or #6 valve cover gasket. The oil runs down both sides to the bottom rear corners of the engine.

That would be my first guess as well. Mine seep, even after replacing them after a while.

 

[BIG C]

Mine turned out to be the valve cover gasket on #6. The ARP stud was not turned in all the way and the valve cover was hitting it not causing a good seal. The front turned out to be the bolts came loose on the front cover to the gear housing. Tightened them down and no more leaks. Actually Im still getting a few small leaks but from what I can tell its just the left over residue oil from the major leaks that I did have. They are getting smaller each time I drive the truck and I can finally park in the garage again!!!



Thanks everyone!!



Chad