# 1991 Suburban 350 oil pan gasket woes



## daniel_bergamini (Aug 25, 2003)

1991 Chevy V1500 Suburban 4wd 350ci (5.7l) v8

Last weekend it started a pretty serious leak from what I believe (hope) to be the oil pan gasket around the lower pulley. I can't see any evidence of oil from any higher, and it’s definitely coming from that general area. I spoke with a few people who all believe it’s likely to be the oil pan gasket. Anyway, I got all my tools together and started on the project early this morning but I’m having a few problems.

I’ve managed to get to almost all the bolts out except the rear two (near the bell housing). Do I need to remove that bell housing cover to get those two last screws out?

I started to remove the bell housing, got the two supports off, but snapped head of the first (15mm!?!) bolt holding the bell housing cover on (the bottom driver side bolt). What exactly does this cover protect and am I going to have trouble if I snap a few more trying to get them off?

If I don’t need to remove it, what is the best approach for getting those last two 1/2 inch bolts out?

If I do need to remove it, what is the best way to keep from snapping any more bolts?

Assuming I do get this project ever done and the truck drives again is the broken bolt something to worry about? Should I try and get it out myself or bring it to someone?

Thanks in advance.


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## Tarkus (Nov 19, 2004)

If it started suddenly and seriously I doubt it is the pan gasket. My bet is that the front main seal is leaking. It is not to hatefull to change and actually I would rather do one of them than a pan seal. You will need to borrow or buy a harmonic damper puller though.


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## daniel_bergamini (Aug 25, 2003)

Tarkus said:


> I would rather do one of them than a pan seal.


I'm not attached to the theory it's the pan gasket, especially now. Now I wish I wasn't doing it, but I need to at least decide if I can finish this project or try and put it back together and limp/tow it over to a mechanic to take care of. Any thoughts on getting the pan down or shold I bail?

And the snapped bolt?


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## Tarkus (Nov 19, 2004)

daniel_bergamini said:


> I'm not attached to the theory it's the pan gasket, especially now. Now I wish I wasn't doing it, but I need to at least decide if I can finish this project or try and put it back together and limp/tow it over to a mechanic to take care of. Any thoughts on getting the pan down or shold I bail?
> 
> And the snapped bolt?


It is not hard to take pan down if it is a 4x4 but I would not bother. Pans tend to seep slowly over time. Sudden leaks are usually a seal failure. You do not need to drop pan to change front seal.


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## daniel_bergamini (Aug 25, 2003)

Tarkus said:


> It is not hard to take pan down if it is a 4x4 but I would not bother. Pans tend to seep slowly over time. Sudden leaks are usually a seal failure. You do not need to drop pan to change front seal.


We only really drive the trunk on weekends, and it's recently dropped below freezing at night. For us it seemed pretty sudden and I think I would have noticed a slow leek. I never poped the seal on the pan, I left the front 2 and rear 2 bolts in place. Think it's worth trying to bolt it all back up again and hope it doesn't now leak? I'll probably just bring it somewhere for the front seal, unless it's a real quick job. What is it and what is the procedure for replacing it? Thanks in advance.


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## Tarkus (Nov 19, 2004)

daniel_bergamini said:


> We only really drive the trunk on weekends, and it's recently dropped below freezing at night. For us it seemed pretty sudden and I think I would have noticed a slow leek. I never poped the seal on the pan, I left the front 2 and rear 2 bolts in place. Think it's worth trying to bolt it all back up again and hope it doesn't now leak? I'll probably just bring it somewhere for the front seal, unless it's a real quick job. What is it and what is the procedure for replacing it? Thanks in advance.


If you never pop'ed it, I doubt it will leak. On the front main seal. You may have removed fan blade and radiator shroad to gain some room but basically you remove belt and maine pulley from engine dampner (on front of crankshaft) and remove the singel large bolt in center of it. You can buy a dampner puller for 10 or 15 bucks and use it to pull dampner and expose seal. Pry out old seal, tap in a new one into place. Wet the seal contact area with oil then install dampner and use large center bolt and crank to pull dampner back into place. Put the rest back together and you are done.


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## daniel_bergamini (Aug 25, 2003)

That sounds like much more fun and a good reason to head back to autozone and another justification for strangling the guy who gave me the oil pan gasket for a 94-98 Ford 5.8L V8.


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## lawnmedic (Jan 9, 2004)

Yes it is a fairly easy job, but a would pull the radiator out first. This will give you a lot more room, and if you slip one time with a wrench you will be buying a new one....


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## Tarkus (Nov 19, 2004)

lawnmedic said:


> Yes it is a fairly easy job, but a would pull the radiator out first. This will give you a lot more room, and if you slip one time with a wrench you will be buying a new one....


In that year 4x4 burb there is a lot of room between radiator and front of engine. No need to pull it. I do tape a thick piece of cardboard or such on back of radiator though as a safety.


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## daniel_bergamini (Aug 25, 2003)

Tarkus said:


> It is not hard to take pan down if it is a 4x4 but I would not bother. Pans tend to seep slowly over time. Sudden leaks are usually a seal failure. You do not need to drop pan to change front seal.


I buttoned up the oil pan (which I never got off in the first place), put a new filter on and put enough oil into it to pull the truck into the garage where it's a little warmer and easier to get under.

Who knows if the anecdotal information I gave you is anywhere near accurate as far as when it started leaking and the rate... I got the front main seal and balancer puller and once I got the balancer off, I could clearly see the front main seal and the front of the oil pan gasket. The front main seal is dry as a bone, and I can clearly see where the fresh oil is coming out of the front of the oil pan gasket.

Back to my original question… How do I get the rear 2 bolts out of the oil pan gasket, and once I have it out will I have any other problems removing the pan and replacing it with the engine in the truck. Please remember I was having trouble getting the bolts out of the flywheel cover without breaking. Thanks again guys.

Any chance that some of that "leak stopper/gasket freshener" stuff will get a me few more miles without leaking or is it just a waste of time/money and chance gumming up the engine?


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## Tarkus (Nov 19, 2004)

daniel_bergamini said:


> I buttoned up the oil pan (which I never got off in the first place), put a new filter on and put enough oil into it to pull the truck into the garage where it's a little warmer and easier to get under.
> 
> Who knows if the anecdotal information I gave you is anywhere near accurate as far as when it started leaking and the rate... I got the front main seal and balancer puller and once I got the balancer off, I could clearly see the front main seal and the front of the oil pan gasket. The front main seal is dry as a bone, and I can clearly see where the fresh oil is coming out of the front of the oil pan gasket.
> 
> ...


My son blew his engine with some gasket sealer in it within a few days of putting it in. The solvent in it that is supposed to swell seals cut some sludge loose too (it was a old car) and plugged filter and took out bearings. You can use a flexible drive on a socket to get rear bolts out and back it and I trust that you did replace front seal anyway while it was down.


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## daniel_bergamini (Aug 25, 2003)

Tarkus said:


> My son blew his engine with some gasket sealer in it within a few days of putting it in. The solvent in it that is supposed to swell seals cut some sludge loose too (it was a old car) and plugged filter and took out bearings. You can use a flexible drive on a socket to get rear bolts out and back it and I trust that you did replace front seal anyway while it was down.


Hopefully I can get at it better in the garage. From the last time I looked those two bolts were at least 1/2 covered by that plate/cover. Maybe I can get in there and get it out with an open-end wrench or crows foot or something.

It's still all apart, I'll probably pull the seal while I can get at it. For the record I ended up pulling the top radiator shroud and fan/cluch assembly and put a rug down in front of exposed radiator and there was plenty of space.

Edit: What should the torque be for the pan when I'm finished, and what would you try tightening to maximum to see if that will stop/slow the leak with the old gasket?


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## Tarkus (Nov 19, 2004)

You can remove the splash shield on bell housing front if you want to for better access. On torque no more than about 25 to 30 inch lbs of torque ans recheck them after engine heats up and cools back down the first time.


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## daniel_bergamini (Aug 25, 2003)

Ok, I'm still working on this one. I have been systematically removing everything from the undercarrage of the truck trying to get the oilpan off. This truck has the expansion oil cooler (I think that's what it's called) and there is this little manifold with 2 pretty big oil lines that is held onto the block with a few allen headed bolts. While trying to take it off, I think I snapped the hard gasket that went between it and the block. Anyone know what the official name of that gasket is?


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## Rick Loncosky (Dec 14, 2002)

The component you're talking about is the oil cooler adapter. It's between the block and the oil filter. I had mine off same kind of vehicle, don't remember a gasket. Not to say there isn't one. I found my leak to be oil coming out around the crankshaft and the inside of the balancer. I put a little sealer on the inside of the hub before you reinstall it. Any excess will come out the front under the big washer. Aren't the bolts at the rear of the pan the next size up then the ones on the side? Hope this helps, Rick.


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## daniel_bergamini (Aug 25, 2003)

Rick Loncosky said:


> Aren't the bolts at the rear of the pan the next size up then the ones on the side? Hope this helps, Rick.


The 2 front bolts and rear nuts are bigger than the ones all up the sides. The ones in the back (next to the tranny) are actually threaded male torx bolts with nuts.


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## Rick Loncosky (Dec 14, 2002)

Dan, have you gotten the pan off yet? I think this is a one piece gasket and you might have to pry the pan down with putty knife. They get stuck along the front and rear from my experience. Rick.


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## daniel_bergamini (Aug 25, 2003)

Rick Loncosky said:


> Dan, have you gotten the pan off yet?


I finally got everything down. The rubber gasket set I bought is 4 piece 2 gaskets for above the oil cooler adapter, the pan gasket and an o-ring I don't immediately see. It's got some nice plastic contractable bolts that will temporarily hold the gasket up while you get the pan on. We'll see how it goes. Anyone in NH want to buy a 91 burb?


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## daniel_bergamini (Aug 25, 2003)

*Success! sort of.*

Ok, I got everything buttoned back up and it's no longer leaking... from the oil pan. I must have put too much stress on the oil cooler lines as one of them appears to be leaking from where it is crimped steel lines to the hose around the front engine support. Do I need to replace the whole set of lines, or can I just recrimp this connection? Is it called an oil cooler line? Thanks in advance.


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## JMR (Feb 24, 2003)

Yes, it sounds like you need to replace the lines. I would NOT recrimp, you would be just asking for trouble.


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