Oil Leak

[D265]

I've got a 4.3L Mercruiser with an oil leak. It's coming from the timing cover area. I just pulled the engine, dropped the pan and installed a new oil pan gasket and timing cover. I torqued everything down good and added some gasket sealant to the corners before doing so.

Finally get everything back together and it still leaks! Hard to see up there what it could be exactly. Leak is definitely a lot less than it was before, looks to come straight down. I took the harmonic balancer puller back to AutoZone so I haven't pulled it again to see if maybe the leak is coming from somewhere else.

Is it possible something else is leaking in that area? I felt like I did a pretty good job. Can't believe I might have to take it to a shop after all that.

 

[alldodge]

What is the motor serial number?
Hey achris this is in your area

 

[dubs283]

I torqued everything down good and added some gasket sealant to the corners before doing so.

torqued good vs. torqued to spec is different. if its the plastic cover and aluminum pan the torque specs are pretty light, over torquing can warp stuff pretty easily

did you put a dab of permatex in the keyway on the balancer?

 

[D265]

I did put a dab on the keyway, maybe it needed more. Engine serial number is 0W653916. Really doubt the timing cover is over torqued, maybe the pan a bit.

 

[alldodge]

I found the threads from Chris, he says need to replace the pan and cover with GM and not Merc

https://forums.iboats.com/forum/eng...outdrives/10289148-mercruiser-4-3mpi-oil-leak

 

[D265]

I found the threads from Chris, he says need to replace the pan and cover with GM and not Merc

https://forums.iboats.com/forum/eng...outdrives/10289148-mercruiser-4-3mpi-oil-leak

I've looked at his thread. Cover is GM. I didn't replace the pan for two reasons:

1. There wasn't anything wrong with it I could see. Everything looked uniform across the mating surface

2. GM doesn't have a direct replacement for my pan from what I can tell. There's two "fins" on each side at the back that line up with the flywheel cover. They don't do anything to hold oil but they do align with that cover. Not sure if that would really make a difference or not.

 

[Furbird]

After having done an oil pan reseal on my 6.0 4X4 truck and having it still leak, never again will I replace a gasket without using a secondary layer of permatex or equivalent (that black stuff is AMAZING) on every mating surface along with the gasket. I did this to the trans pan gasket and it's dry as a bone.

 

[D265]

After having done an oil pan reseal on my 6.0 4X4 truck and having it still leak, never again will I replace a gasket without using a secondary layer of permatex or equivalent (that black stuff is AMAZING) on every mating surface along with the gasket. I did this to the trans pan gasket and it's dry as a bone.

This is what I'm thinking is going to have to be done. I plan to pull the harmonic balancer and get a look back there to see where the leak is. Might be that crankshaft seal above the oil pan gasket.

If it's not, I'll pull the engine and use a generous amount of sealant along the oil pan gasket where it mates with the timing cover.

 

[Furbird]

Wouldn't the new cover have a new crank seal in it?

 

[dubs283]

Might be that crankshaft seal above the oil pan gasket.

the new cover should have had a new seal in it, you need to oil the lips before installing the balancer

Really doubt the timing cover is over torqued

106 lb/in which equals 8-9 lb/ft, very easy to over torque without a calibrated wrench

 

[achris]

Your engine serial number is very close to mine, so it's very possible you have one of the 'bad' sumps. The deformation is VERY small, around 1mm, incredible difficult to detect by eye. But it's enough to crack to timing cover, every time.

The ONLY way to fix it permanently is to replace the sump with a new one. Trust me, I tried all the options... :facepalm:

Chris....

 

[D265]

Your engine serial number is very close to mine, so it's very possible you have one of the 'bad' sumps. The deformation is VERY small, around 1mm, incredible difficult to detect by eye. But it's enough to crack to timing cover, every time.

The ONLY way to fix it permanently is to replace the sump with a new one. Trust me, I tried all the options... :facepalm:

Chris....

Could you post a link to the one you recommend? Does yours have the fins on the back?

Also my timing cover isn't cracked and it's leaking immediately after replacement. Are you saying your leak was from a crack in your timing cover?

 

[D265]

the new cover should have had a new seal in it, you need to oil the lips before installing the balancer



106 lb/in which equals 8-9 lb/ft, very easy to over torque without a calibrated wrench

Have you installed one of these personally? When you put it on, the bolts seat super firmly with almost no torque. It's like they hit a wall, that's why I'm saying I doubt they're over torqued.

 

[achris]

Have you installed one of these personally? When you put it on, the bolts seat super firmly with almost no torque. It's like they hit a wall, that's why I'm saying I doubt they're over torqued.

They are a 'shouldered' bolt. Inside a rubber sleeve in the cover. If you over-torque them, all you'll do is damage the block casting.

 

[dubs283]

Have you installed one of these personally?

only about two dozen, torqued to spec

never had one leak, even when reusing the original oil pan, some of which leaked before the repair

ymmv

 

[D265]

only about two dozen, torqued to spec

never had one leak, even when reusing the original oil pan, some of which leaked before the repair

ymmv

Seems like the leak is more on the oil pan side of things. I didn't use a torque wrench but I know the timing cover isn't over torqued. All the timing cover does is hang there, it's the pan that pushes up to it.

Seems weird I don't have the same issue at the back of the engine which has a similar gasket.. Maybe it's the plastic timing cover that has too much flex.

 

[D265]

What do you guys think of this one?

https://www.holley.com/products/accessories/timing_covers/parts/21-152

 

[achris]

What do you guys think of this one?

https://www.holley.com/products/acce...s/parts/21-152

That's a 10 bolt cover, for a V8, not for a V6 with a balance shaft.

Could you post a link to the one you recommend? Does yours have the fins on the back?

They are all the same. It's a GM product, not a Mercruiser product. Merc buy then, put a 'Mercury Marine' label on it and add 40% for the privileged, and sell it to unsuspecting clients.

Here's the first one I found...

https://www.gmpartsdirect.com/oem-parts/gm-oil-pan-12597153

Chris......

 

[D265]

That's a 10 bolt cover, for a V8, not for a V6 with a balance shaft.



They are all the same. It's a GM product, not a Mercruiser product. Merc buy then, put a 'Mercury Marine' label on it and add 40% for the privileged, and sell it to unsuspecting clients.

Here's the first one I found...

https://www.gmpartsdirect.com/oem-parts/gm-oil-pan-12597153

Chris......

Says on the Holley website it's good for the v6 you just omit the bolts at 10 and 2.

 

[Scott Danforth]

Says on the Holley website it's good for the v6 you just omit the bolts at 10 and 2.

it may fit the non-balance shaft motor (1985-1992), however it will not fit the 93 and later balance shaft motors.