Engine/Transmission (1998.5 - 2002) oil leak tappet cover?

[woodtrucker]

In my 02 cummins I'm a gallon low after oil change. Usually 1/4" above stick at oil change and 1/4" below stick when it's time to change. After last oil change I tightened down my oil pan gasket bolts to be sure that wasn't where the leak was coming from and cycled again and it leaked a little less but was still almost a gallon low.
Now I see that it looks like the oil is leaking down the side of the block behind the starter. Would that most likely be the tappet cover? It looks like it's leaking down the side of the block then down to back edge of the oil pan gasket and off the truck.
Strangely, I don't hardly see any oil in my driveway ever so it always leaks when running but not sitting. And it's apparently leaking a lot more than I had thought since it's a gallon low at each oil change interval?
Any suggestions? Should go ahead pull tappet cover? Would anything else leak near starter area?
All else is solid as a rock on that baby! Got 106k on it now. Bought it at 83k.
sp

 

[petersonj]

Should go ahead pull tappet cover? Would anything else leak near starter area?

There are several sources for oil leaks on the left side of the engine - vacuum pump seal or mounting flange, vacuum pump oil feed and drain, engine oil pressure sensor, front timing cover, oil pan, valve cover, and the tappet cover. The tappet cover and the oil pan are the most labor intensive repair, but the least likely cause. All of the mentioned leaks can be difficult to diagnose because leaking oil usually does not travel in a vertical path as one would think and it doesn't take much leaking oil to make a mess.

I would start by cleaning the affected area with Brake Kleen and begin monitoring the leak.

Also, leaking vacuum lines can contribute to the problem since the vacuum pump exhausts into the engine crankcase.

At 260,000 plus miles I have had to repair two leaks - the vacuum pump mounting flange and the vacuum pump seal. I also had to replace leaking vacuum lines at various times (indicated by excessive vapor coming the crankcase breather). At this point in the life of the truck, oil consumption is less than two quarts between 8,000 mile oil changes.

Maybe the tappet cover is leaking on your truck, but I recommend checking other oil leak sources first.

- John

 

[dward]

I'm in the process of pulling my vacuum pump now to replace the seals. This is a common area for a leak and while running it would leak a drop about every 5 secs. It will cover the left side and bottom of the truck with oil.
A shop wanted $1200 to replace it but I just got the seal kit from Goulds Gear for around $50.
I'm also pulling the radiator to clean it and replace belts and hoses etc. I'm thinking around 6-8 hrs taking my time and removing more stuff than needed for just the pump.
Gould makes a great video and it looks like a straight forward job.
Not sure about the tappet cover but I think that may be a more involved job.
Look behind the IP at the cover to see if its leaking. Fortunately, mine is dry. Also, reroute your crankcase vent hose from the bottle to under the truck. This will keep the radiator clean.

 

[BigPapa]

There is also a gasket behind the lift pump bracket. It seals the hole in the block where the 12V mechanical lift pump goes.

 

[klcammie]

If the tappet cover is leaking it is not to hard to fix, just takes a bit of time. This is a pix of mine. It didn't seem to be a bad leak until I got to this point.

 

[klcammie]

If the tappet cover is leaking it is not to hard to fix, just takes a bit of time.

 

[woodtrucker]

I think it's leaking back there near the lift pump b/c I don't see much oil except back toward the back of the engine.
Gonna get under the hood tonite and find it! Thanks for the tips!