6.2 rear main Q?

[desertrat67]

Would my 90 have a different rear main than an earlier year?

I aks because I replaced the oil pan gasket an rear main seal last year, and the new RMS was about 1/4" longer than what was replaced(I did ask for a gasket for my year truck). I put it in thinking it wouldn't be an issue.

Now I watch oil drip out of the engine at a bout a drop per second or two. I am going to replace this again, but want to make sure there aren't two style seals.

 

[tRustyK5]

2 piece RMS? I think they all were for our era of trucks anyways. I recall trimming mine to suit, then running a very thin bead of rtv from the seal itself out to the gasket area for the pan. Dry as a bone back there now...

Without the rtv oil finds its way out between the block and the rear main cap in the area between the seal and the pan gasket.

Rene

 

[desertrat67]

It was only a single piece.

This is the same as what I put in.

There really wasn't a way to trim it because it flares out at the ends to fit into the notches in the block.

 

[kennyw]

That is just the oil pan gasket... there is another seal that goes around the crankshaft. Your engine has a 2 piece rear main seal that requires the removal of the last main cap to replace it.

 

[desertrat67]

See the piece on the far right of the pic? That is what I am talking about. The horseshoe looking thing. This is what I replaced that was a little longer than the one I removed. I always thought this was the rear main.

 

[tRustyK5]

There is a two piece seal that goes in a groove in the rearmost main cap and the block above that main cap. You need a small wooden dowel to push the old upper seal out of the block, and to push the new seal half back into the upper groove. The lower half of the seal just drops into the removed main cap. A very thin line of RTV along the part line from the seal half's out to the pan gasket and you're good to go.

The rear main seal rides on the the end of the crankshaft itself just behind the last main bearing

This talks about an asbestos rope seal, but I don't know if that is even available anymore. When I replaced mine all they had was a two piece rubber seal. The rubber seal has two 'lips' raised up that ride on the polished end of the crank. I put a slight skim of oil on both halfs to keep the rubber from 'friction burning' at intial start-up.

Rene

 

[kennyw]

See the piece on the far right of the pic? That is what I am talking about. The horseshoe looking thing. This is what I replaced that was a little longer than the one I removed. I always thought this was the rear main.

No, that is just an oil pan gasket. It probably was not the only source of the leak when you did the work. Replace the whole pan gasket again while you replace the rear main and you should be good to go.

 

[AJMBLAZER]

Any truth that you can do this without dropping the pan? I heard someone say that on SteelSoldiers.com a while ago.

 

[tRustyK5]

Ummm, no. The rear main cap is inside of said pan...so feel free to let that person know they are grossly mis-informed.

Rene

 

[AJMBLAZER]

Maybe it was the pan gasket then...I dunno. I'm not terribly good with engines and their internal workings. I've done exactly one cylinder head on a 4 cylinder engine and taken the intake manifold and valve covers off of a TBI 350. Nothing else.

Guy said something about making some kind of a scraping tool and such. I dunno.

If the pan comes off to do this...can you do the front main seal? I'm pretty sure mine are both leaking. I have leaks out of each end and they're the most likely culprits.

 

[kennyw]

You have to drop the pan for the rear main seal or you can not remove the bearing cap. The front main seal does not require removing the oil pan. It does require removing the harmonic balancer though.

 

[desertrat67]

The rear main seal rides on the the end of the crankshaft itself just behind the last main bearing

Rene

As soon as I saw this, I remeber having seen it in the one 6.2 I took apart aobut 4 years ago. My leaks are solely oil pan gasket related. I think my pan is not flat along the surface though. I relpaced the gaskets today and it started lkeaking immediately from the front(engine not running) and down the left side.

Would using RTV be recomended? I really need this to stop leaking and don't have the dough to get a new oil pan. I just found out I also have a head gasket leaking(you can see small bubbles forming at the left rear of the engine where the block and head go together).

I am getting really pissed off right now.

 

[kennyw]

I have a good used oil pan I can sell you cheap if you don't think yours is very flat. It should only need a little RTV at the joints between the two gaskets.

 

[desertrat67]

I am on a short deadline to get this thing ready for a trip to So Cal. I appreciate the offer, but there are about 5 6.2s and a 6.5 at the local yard I could go get If it comes down to it. There usedto be a Sub with 2 6.2s in the cargo area. Would have made pulling the pan cake. I didn't see it on the last trip out though. :

 

[tRustyK5]

Using a straight edge and a small hammer you can massage the sealing surface back to straight enough in most cases. I do oil pan gaskets the same way I used to do sbc valve cover gaskets. Firstly I only use the neoprene gaskets...I'm done with cork. I thoroughly clean the sealing surface of the pan, brake kleen and a scotch brite pad until it's completely clear of any oily residue, or old gasket material.

I then do a very thin bead of RTV on the pan and drop the gasket onto the pan. I let it set up for a few hours so I know the gasket is completely sealed to the pan, then add a thin bead of rtv on top of the gasket and put the pan into place. I try to keep very even pressure on the center of the pan while I turn in the 4 corner bolts. Then I spin in all the other bolts...

I don't tighten a single bolt until they're all in, and when I do tighten them it's methodically. Think OCD. bring them all up just til there is a little rotational resistance. Starting with the corner bolts first I turn them in another 1/4 turn, then ever second bolt between the corners, then the remaining until they're all 'tighter'. Repeat until they're all to spec and you should get a nice even crush and a good reliable seal.

Rene

 

[desertrat67]

Using a straight edge and a small hammer you can massage the sealing surface back to straight enough in most cases. I do oil pan gaskets the same way I used to do sbc valve cover gaskets.

I just used a hammer and tapped the area around the holes until they looked mostly flat when viewed from the side.

Firstly I only use the neoprene gaskets...I'm done with cork.

I don't like cork either. The only ones available locally are paper/cardboard thingys. If this one goes again, I will search for a neoprene one.

I thoroughly clean the sealing surface of the pan, brake kleen and a scotch brite pad until it's completely clear of any oily residue, or old gasket material.

Yup.

I then do a very thin bead of RTV on the pan and drop the gasket onto the pan. I let it set up for a few hours so I know the gasket is completely sealed to the pan, then add a thin bead of rtv on top of the gasket and put the pan into place. I try to keep very even pressure on the center of the pan while I turn in the 4 corner bolts. Then I spin in all the other bolts...

I went straight RTV this time. I laid a good bead makign sure to circle the bolt holes, then I let it dry for about 10-15 minutes. I put the pan on, then added the bolts in a similar fashion to what you mentioned. got a couple rear ones in, then a few fronts, only enought to hold it up then added the rest and tightened only enought to get the RTV let me know the RTV was flattened all the way around.

I don't tighten a single bolt until they're all in, and when I do tighten them it's methodically. Think OCD. bring them all up just til there is a little rotational resistance. Starting with the corner bolts first I turn them in another 1/4 turn, then ever second bolt between the corners, then the remaining until they're all 'tighter'. Repeat until they're all to spec and you should get a nice even crush and a good reliable seal.

Rene

I then proceded to the hospital with my 15 month old and stayed there for 3 nights. Upon return I tightened all the bolts in an side to side/front to back pattern. I added oil and have yet to see any drips. THe last replacement was dripping as soon as I added oil. I have the batteries on a charger now and will be starting it up in about an hour to see if it leakes while running.

Thanks for the help and clarification.

 

[Mikey von]

I hope your 15 month old is all right.

 

[desertrat67]

He is home, breathing well, finishing up some antibiotics(he had pneumonia), and terrorizing the dog. DOing much better. Thank you.

The oil pan no longer leaks either! Now I get to replace a head gasket this weekend. yeah

 

[tRustyK5]

Glad your son is doing better! Also glad to hear the pan no longer leaks...I hate leaky vehicles.

Rene

 

[desertrat67]

Me too. On both. As for the leaky vehicle, this thing has left a huge stain on the road where I park it. I hated that. Now, off to drain the cooling system and replace a head gasket.