Chevy 454 Motor Oil Leak

[ScottyBye]

Hope that I am posting this in the right section!

After my last road trip this past weekend I noticed a small pool of oil under my RV...
Upon inspecting the undercarriage I found that the area of the engine oil pan and transmission bell housing was pretty saturated with motor oil.
OMG I thought....right....
So I immediately thought that maybe just maybe I has a loose oil filter or drain plug, since I recently changed the oil in the unit. NOPE....
So I cleaned up the mess as best I could using rags and degreaser, ect....

OK so now I figured it would be much easier to trace the leak to its origin.

Next thought was maybe an oil pan gasket leak, but that seems ok.

Kept looking down under the engine compartment, but no luck.

Next I inspected the top of engine via doghouse inside the coach.

Valve cover gaskets sweating a little but nothing obvious for the amount of oil that was on the ground. Did however find a small squirrel nest with some pine cones, and mushrooms that were not local to my area (Calgary, Alberta, Canada)...lol

So to no avail,,, I was at a stand still and decided to make a call to a mobile auto mechanic who just happened to be in my area, and dropped by to lend some assistance (for a fee of coarse)...

With 2 sets of eyes now, we started the engine and again began looking for leaks.

Here is what we found.....
The leak is somewhere on the top side of the engine.
He suspects either the rear intake gasket or maybe the distributer gasket.
But with out actually dismantling the mess that's on the top side of the engine via the doghouse that's just a best guess scenario at this point.

So before I go any further, and spend a bunch of money that I could definitely use elsewhere I thought that I would post my problem here and see if anyone has some input or knowledge they would like to share.

I was also told by a friend to check the oil sensor sending unit, but neither of us knows where that may be located...

If someone knows where I could get a diagram showing the parts, and components view of the 454 engine that would be great... The unit is a 1996 which I am told is the 1st year of the VORTEC 454.... but I don't know if that part is true.

I will be using MR Google as well, but posting here 1st

Ideas....???

[CampDaven]

I had a 96 with the 454.
If you take the cover (doghouse) off inside, you should be able to take off the air cleaner and other stuff so you can see the top rear of the motor. Flashlight and mirror may help.
Best wishes


Dave and Nola, RV Mutants

[NHRA225]

The Oil Pressure sending unit is or was near the Oil Filter Housing. 'Again we need more info ! Dripping or Pouring out Oil ?

[LETMGROW]

Finding an oil leak on a dirty engine can be difficult. Clean all surfaces you can get to with either an engine shampoo or brake clean and dry thoroughly. Do this on a cool engine. Some of these cleaners are highly combustable.
If the leak doesn't show up you can add a tracer dye to the oil which will look almost like it is glowing when it appears. You might have to run the engine several minutes before the leak shows up. Keep your hands away from any moving parts. The dye is available at most auto parts stores. If nothing shows up on the top of the engine you can remove the lower flywheel cover from the front of the transmission so you can look between the flywheel (flexplate ) and the rear of the engine block. It is possible you could have a leak at the rear main bearing seal. If that is the culprit you have a major job on your hands. This job would require removing the transmission and flexplate for access to the seal.
Lynn

[ScottyBye]

Originally Posted by CampDaven

I had a 96 with the 454.
If you take the cover (doghouse) off inside, you should be able to take off the air cleaner and other stuff so you can see the top rear of the motor. Flashlight and mirror may help.
Best wishes


Dave and Nola, RV Mutants

Thanks I will give it a try

[ScottyBye]

Originally Posted by NHRA225

The Oil Pressure sending unit is or was near the Oil Filter Housing. 'Again we need more info ! Dripping or Pouring out Oil ?

The oil drip seems to start about 1 minute after starting the engine.
Seems to be pooloing on the top side of the motor, then running down the side of motor near the oil filter, then onto the ground. The DRIP is about a drop ever 10-15 seconds...

[ScottyBye]

Originally Posted by LETMGROW

Finding an oil leak on a dirty engine can be difficult. Clean all surfaces you can get to with either an engine shampoo or brake clean and dry thoroughly. Do this on a cool engine. Some of these cleaners are highly combustable.
If the leak doesn't show up you can add a tracer dye to the oil which will look almost like it is glowing when it appears. You might have to run the engine several minutes before the leak shows up. Keep your hands away from any moving parts. The dye is available at most auto parts stores. If nothing shows up on the top of the engine you can remove the lower flywheel cover from the front of the transmission so you can look between the flywheel (flexplate ) and the rear of the engine block. It is possible you could have a leak at the rear main bearing seal. If that is the culprit you have a major job on your hands. This job would require removing the transmission and flexplate for access to the seal.
Lynn

Thanks for the input.
I have used brake clean and got 90% of the oil mess cleaned up.
The leak seems to be coming from the top side of the engine.
So far I am thinking the rear gasket on the intake or even possible the distributor seal. I will keep digging.

God!.... I hope it's not the rear main engine seal as you mentioned...

[ga traveler]

Originally Posted by ScottyBye

Thanks for the input.
I have used brake clean and got 90% of the oil mess cleaned up.
The leak seems to be coming from the top side of the engine.
So far I am thinking the rear gasket on the intake or even possible the distributor seal. I will keep digging.

God!.... I hope it's not the rear main engine seal as you mentioned...

The rear main seal would not leak at the top of the engine. Have you checked the PCV valve?

[LETMGROW]

Originally Posted by ScottyBye

Thanks for the input.
I have used brake clean and got 90% of the oil mess cleaned up.
The leak seems to be coming from the top side of the engine.
So far I am thinking the rear gasket on the intake or even possible the distributor seal. I will keep digging.

God!.... I hope it's not the rear main engine seal as you mentioned...

If it is at the top of the engine this more than likely is either the distributor shaft seal and gasket or the seal is leaking between the engine block and the intake manifold. Most of these engines do not have a seal between the block and intake but use a high temperature RTV sealer in place of the seal. Using the RTV sealer is my preferred method.
How many miles do you have on this engine?
Lynn

[NHRA225]

Originally Posted by ScottyBye

The oil drip seems to start about 1 minute after starting the engine.
Seems to be pooloing on the top side of the motor, then running down the side of motor near the oil filter, then onto the ground. The DRIP is about a drop ever 10-15 seconds...

Check the Valve Cover gasket.
If you checked it then check it again !

[dwhit]

Your description fit our problem exactly. But our oil pressure GAUGE registered ZERO which lead us straight to the problem.

Our 1999 454 Damon Daybreak had her oil pressure sender leak a lot of oil...scary problem. Remove the doghouse the sending unit is far to the rear close to where the transmission mounts. It's right on top...left of center and easy to access and obvious where it's leaking.

[dieselclacker]

Originally Posted by dwhit

Your description fit our problem exactly. But our oil pressure GAUGE registered ZERO which lead us straight to the problem.

Our 1999 454 Damon Daybreak had her oil pressure sender leak a lot of oil...scary problem. Remove the doghouse the sending unit is far to the rear close to where the transmission mounts. It's right on top...left of center and easy to access and obvious where it's leaking.

Oil pressure sending unit would be the first place to look for the leak as described above. Next would be rear surface sealing of intake manifold to engine block.

[ScottyBye]

Originally Posted by LETMGROW

If it is at the top of the engine this more than likely is either the distributor shaft seal and gasket or the seal is leaking between the engine block and the intake manifold. Most of these engines do not have a seal between the block and intake but use a high temperature RTV sealer in place of the seal. Using the RTV sealer is my preferred method.
How many miles do you have on this engine?
Lynn

Thanks for this info... I will check it out.

[ScottyBye]

Originally Posted by dieselclacker

Oil pressure sending unit would be the first place to look for the leak as described above. Next would be rear surface sealing of intake manifold to engine block.

I will hopefully get my ass in gear and start working on this over the weekend...Thanks for the input