The aggravation continues...same oil leak at flywheel

[CaptainMak]

Took the 2003 5.0L Merc out this winter to fix an oil drip at the back of motor (flywheel area).

Replaced the oil pan gasket and rear main seal, making sure all corners and joints of the oil pan were properly sealed with RTV silicone.

Put everything together, popped the block into the boat, started up and got the same leak. After running the motor about 2 mins, I get a drip about every 5 - 10 seconds onto the bottom of the flywheel bellhousing (inside).

It seems like it's dripping off the main seal, but with limited space it's hard to see if it's dripping from there or dripping down the block and then off the main seal housing. I KNEW I should have run it on stands before popping it back in. :faint2:

Anything else that could be causing the engine oil leak back there ? I've looked, I don't see anything else it might be.

 

[K-2]

Re: The aggravation continues...same oil leak at flywheel


Did you remove the flywheel when you had the engine out? See anything oily under it?

 

[CaptainMak]

Re: The aggravation continues...same oil leak at flywheel

View attachment 227783 View attachment 227784
Did you remove the flywheel when you had the engine out? See anything oily under it?

Yeah, the flywheel came off and rear main seal got replaced. What is the first diagram showing? I didn't notice the plugs when it was off.

It was oily, just wasn't sure where it was coming from so I replaced the two things that I though would cause this leak, the oil pan gasket and rear main.

 

[K-2]

Re: The aggravation continues...same oil leak at flywheel

The 3 small plugs are the oil galleries, middle one is the main oil gallery, each side of that is galleries for lifters, when the engine is running
there is oil under pressure under these plugs. The big center shiny one is the cam plug, kind of like a freeze plug but it covers the
rear of the cam bore, oil could also leak from there . I can't remember if the oil gallery plugs are screwed in plugs or small press in plugs, kind of like mini freeze plugs. Hopefully some one will know .

 

[Bt Doctur]

Re: The aggravation continues...same oil leak at flywheel

Have installed both types, threaded and core plug like

 

[Watermann]

Re: The aggravation continues...same oil leak at flywheel

Did you check to make sure there wasn't even the tiniest of a groove in the crank main seal surface that would make it continue to leak no matter how many times you put in a new main seal. I believe they make a spedi sleeve to repair them if it does.

 

[NHGuy]

Re: The aggravation continues...same oil leak at flywheel

Stinks that it still leaks. Our motors, with their black paint, can be hard to see oil leaks on. Maybe you could put in some fluorescent oil dye to help be sure you know where its leaking from.
Then run the motor, don't wipe it down, and check all over. Use lights, mirrors, cell phone camera, whatever you can to be sure where the oil is coming from.
By the way, check the power steering too. When I regasketed my motor last year I put it back in the boat and got oily fluid in the bilge. I about cried, I thought it was motor oil. I figured my gasket job had failed til I found my steering leak.
I ended up rebuilding the PS actuator.
Maybe your gasket job is OK. Give it a good inspection to be positive what the problem is.

 

[CaptainMak]

Re: The aggravation continues...same oil leak at flywheel

This leak is definitely coming down the center of the block in the back.
As you know, it tough getting into between the flywheel and the block. I'll try to stick a mirror back there and check out where the leak originates. Quite possibly, as Watermann stated, there might be something with the crank seal housing.

As I stated before, the top of the engine is bone dry (distributor clamp, pressure senders, intake manifold, etc). I'll take a look in the a.m. and let you guys know.

 

[Volphin]

Re: The aggravation continues...same oil leak at flywheel

Well, if it's still leaking, bite the bullet and burn and hour pulling it out. Build a engine cradle out of an old pallet and fire her up. You didn't skimp on parts did you? JK

Some blocks have a oil gallery plug behind the flywheel. You may get lucky.

 

[CaptainMak]

Re: The aggravation continues...same oil leak at flywheel

Well, if it's still leaking, bite the bullet and burn and hour pulling it out. Build a engine cradle out of an old pallet and fire her up. You didn't skimp on parts did you? JK

Some blocks have a oil gallery plug behind the flywheel. You may get lucky.

I'm going to pull it either way considering the second time it will be much faster and easier.

Not sure what parts I could have "skimped out" on ? The seal was a National brand. (pretty good I think). The oil pan gasket was a Fel-Pro brand. Also pretty descent. The RTV silicone I put in the corners where the manual calls for it was also liberally applied. I guess it might be something else I missed... not sure

It's raining pretty darn hard down here today, so working on the boat is outta the question. No luxury of a big enough garage.

 

[CaptainMak]

Re: The aggravation continues...same oil leak at flywheel

Well, I guess I was in a bit of a hurry to install the rear main seal last time, that I think I forgot to replace the crank oil seal HOUSING gasket. (#6 in the pic I attached). If I was a betting man, I'd guess this is the first place I should look when the motor comes out.

One quick Question: Is the oil pan gasket re-usable on the 5.0's ? I'd hate to throw this one away practically new.

 

[Volphin]

Re: The aggravation continues...same oil leak at flywheel

Well, I guess I was in a bit of a hurry to install the rear main seal last time, that I forgot to replace the crank oil seal HOUSING gasket. (#6 in the pic I attached). If I was a betting man, I'd guess this is the first place I should look when the motor comes out.

One quick Question: Is the oil pan gasket re-usable on the 5.0's ? I'd hate to throw this one away practically new.

View attachment 227894

If the gasket is rubber then yes, it is reusable. However, if you are like me, you get a little happy with the RTV in the corners. The gasket can get stuck pretty good and I usually damage it during teardown.

 

[alldodge]

Re: The aggravation continues...same oil leak at flywheel

There is good and bad with silicone. It seals and can take the heat. The bad part about silicone is it is also sort of a lubricate before it dry's. You can use the stuff on both sides of a rubber gasket, and when it gets tightened down it can slide it self out from under where it was put. I use it but sparingly.

 

[CaptainMak]

Re: The aggravation continues...same oil leak at flywheel

If the gasket is rubber then yes, it is reusable. However, if you are like me, you get a little happy with the RTV in the corners. The gasket can get stuck pretty good and I usually damage it during teardown.

Yeah, it was on there pretty good after I went happy with it last time. Ended getting a new one.

Found the leak also. Felt really stupid when I realized that I put the metal brackets that go UNDER the pan between the gasket and block. Don't ask me how. Plain case of dumb assitis.

 

[Bondo]

Re: The aggravation continues...same oil leak at flywheel

Yeah, it was on there pretty good after I went happy with it last time. Ended getting a new one.

Found the leak also. Felt really stupid when I realized that I put the metal brackets that go UNDER the pan between the gasket and block. Don't ask me how. Plain case of dumb assitis.

Ayuh,..... That's a Tough one to diagnose over the internet,..... :lol: