Help needed! Identify this bolt found loose in oil pan?

[85xjwoody]

I noticed the oil pan was sealed using a rubber gasket and had silicone in the corners- could that be a factory job or is it an indicator that the pan has been removed before?

In my opinion that pan has never been off before. The factory used the rubber gasket with silicone at the corners. Every 4.0 I have torn apart, which is over 20, has had that same set up.

 

[Red91Laredo]

So 85xjwoody in your observation the factory used a one piece rubber gasket? I was wrong, mine had cork gaskets on the side rails and rubber on the ends. So maybe someone else did have the pan off before.

That stupid cork was baked on solid. Gasket remover is helping me to scrape it off the block, but most of it was stuck to the pan and was taking forever to remove so I just hit it with a kleen strip disc. Definately the way to go there. I bought the one piece rubber gasket to reseal it.

 

[5-90]

So 85xjwoody in your observation the factory used a one piece rubber gasket? I was wrong, mine had cork gaskets on the side rails and rubber on the ends. So maybe someone else did have the pan off before.

That stupid cork was baked on solid. Gasket remover is helping me to scrape it off the block, but most of it was stuck to the pan and was taking forever to remove so I just hit it with a kleen strip disc. Definately the way to go there. I bought the one piece rubber gasket to reseal it.

I had an 87 that I was the second owner of - the PO had never had the sump off, and it had only silicone in there when I had to tear it off. Replaced it with the 96-up one-piece moulded gasket, no RTV, and didn't have any trouble at all.

 

[Red91Laredo]

Is the gasket different if I ask for one for a '96+ ? And if so whats improved about it? I told them '91 Cherokee and got a one piece Fel-Pro gasket that says it fits '87-'01 Jeeps. If there's a better option I'll take this one back.

 

[Talyn]

The felpro gasket is fine.

As for RTV, you are suppose to put it where the timing cover meets the block and where the rear main cap meets the block. Its not just a factory thing.

That bolt is not engine related. I haven't seen a serrated head like that on any engine related bolts.

 

[Shorty]

That bolt is not engine related. I haven't seen a serrated head like that on any engine related bolts.

X2^^ nothing I've torn into (most everything on a 4.0L) has come with that style head.

 

[Ecomike]

Truth.... Many years ago, I was replacing an 200 ci engine in '65 Ranchero. When I removed the oil pan and began scraping the sludge at the bottom, I found a relatively new 1/2" Snap On wrench at the bottom of the pan. The sludge kept it in place after all the years....

Must have been there from the factory as we were the original owners....

We had a 5-6 ton sand blast pot that had given us trouble for 2 years right out of the factory. Finally they opened up the inspection door and found a tool box of tools inside of it. It was shipped that way. LOL!!!

 

[Red91Laredo]

Well I'm extremely relieved to hear that the bolt didn't come off any internal engine parts. It's weird that I've changed the oil 7 or 8 times and never had that bolt end up sticking out the oil drain hole before. Maybe because I pulled the drain plug with the oil hot instead of just warm? I usually let it cool off for 20-30 minutes but this time I came home from running errands and pulled the plug immediately. I guess the hotter oil started flowing out with enough pressure that it picked up that bolt off the bottom of the sump and carried it to the drain hole.

I needed to replace the pain gasket and probably RMS anyway so at least I didn't pull the pan for absolutely nothing, although I was planning to wait for warmer/drier weather to do it, haha...

 

[ParadiseXJ]

This may be a wild shot in the dark here but it looks like the bolt from the front /bottom of the tranny inspection plate.

Could'a fell in there when the pan was off doing an RMS job. Wouldn't really be missed in reassembly, and could easily be overlooked, and after it was all back together the mechanic/owner could replace it with a diff cover bolt...it doesn't look like a pan bolt to me.

 

[Red91Laredo]

I didn't notice any bolts like this one holding the inspection cover on, just two really small ones and two really big ones, but maybe this one is supposed to be there too. I'll have to check later tonight.

What's up with those huge 17 millimeter bolts & nuts on the inspection cover anyway? They don't seem to be doing anything the smaller machine screws aren't already doing yet they're beefy enough to be control arm bolts...

 

[5-90]

Is the gasket different if I ask for one for a '96+ ? And if so whats improved about it? I told them '91 Cherokee and got a one piece Fel-Pro gasket that says it fits '87-'01 Jeeps. If there's a better option I'll take this one back.

Sounds like Fel-Pro got tired of making two different gaskets, and cut out the four-piece.

You'll be fine. If you have trouble getting the holes to all line up, it helps to tie the gasket to the pan at intervals with fishing line or 4" ny-ties - get it in place, start the screws in the holes with nothing in them, then cut the ties and finish the job.

NB: Do not tighten the first screw until the LAST screw is started! I usually put screws in finger tight, then back them off one full turn - this gives you that little bit of "slop" you so often need to get the rest of the screws lined up...

 

[Ivan]

...........You'll be fine. If you have trouble getting the holes to all line up, it helps to tie the gasket to the pan at intervals with fishing line or 4" ny-ties - get it in place, start the screws in the holes with nothing in them, then cut the ties and finish the job...

I tried the zip tie / rubber band trick to hold the pan gasket in place on the oil pan, and fail miserably with that method. The gasket still managed to move around on me.

I found it a lot easier to tack the gasket to the engine block with a little RTV to hold it in place. Plus you are less likely to wind up with an oil leak from the rear if the gasket doesn't seat well into the rear bearing cap groove, when installing the oil pan.

You don't have to glop the RTV on the mating edge of the engine block ...just a nice thin bead on the engine block works great. Work your way from the back of the engine block to make sure the gasket fits in the rear bearing cap groove. As you move forward, use some of the pan bolts to hold the gasket in place while you set it. Go back and press the gasket really well to the engine block. Wait a bit to let the RTV set, then remove the pan bolts holding the gasket in place. Reinstalling the oil pan will be less challenging that way, than sticking the gasket to the pan itself, and trying to keep the gasket in place with zip ties and such....

 

[2X_01_Jeeps]

Coming late to the thread but it looks like it could be a timing chain cover bolt.

Could have been factory lost debris. I pulled the pan on my '84 and found scads of bearing shavings in the bottom so I pulled the bearing caps and all was fine. Was just scary debris from the factory.

But you have to look hard to prove it's not something coming apart. Don't accept the easy answer first on something like this.

 

[5-90]

I tried the zip tie / rubber band trick to hold the pan gasket in place on the oil pan, and fail miserably with that method. The gasket still managed to move around on me.

I found it a lot easier to tack the gasket to the engine block with a little RTV to hold it in place. Plus you are less likely to wind up with an oil leak from the rear if the gasket doesn't seat well into the rear bearing cap groove, when installing the oil pan.

You don't have to glop the RTV on the mating edge of the engine block ...just a nice thin bead on the engine block works great. Work your way from the back of the engine block to make sure the gasket fits in the rear bearing cap groove. As you move forward, use some of the pan bolts to hold the gasket in place while you set it. Go back and press the gasket really well to the engine block. Wait a bit to let the RTV set, then remove the pan bolts holding the gasket in place. Reinstalling the oil pan will be less challenging that way, than sticking the gasket to the pan itself, and trying to keep the gasket in place with zip ties and such....

True.

I've also worked on some Fords over the years, and Fel-Pro used to do little split plastic studs with a 1/4"-20 thread for Fords. I keep them.

They thread into the hole, then you push the gasket up, and it 'clicks' past shoulders on the plastic stud. Push the sump up, click it onto the plastic bits, and start screws.

Remove the plastic bits (but I don't throw them away until they don't "click" anymore...)

I'm ruminating on making something semi-permanent one of these days, I just haven't figured out how. Once I do, I'll probably make them in 1/4"-20 (engine oil sump) and M6-1.0 (AW4 oil sump) and have them as kits of six or eight.

I also found it helpful to put four or six studs spaced wide on the "long rails" - put the gasket up, put the pan up, and it stays put with one hand while starting screws with the other. Nuts go on last, and come off last next time (loosen the stud nuts down to the end, but don't take them off until you have all of the screws out.) Get 1/4"-20x3/4" or 1" studs (1" is overkill, but works well,) last time I used a kit for stamped valve covers on a Small Block Chevvy. Retain with LocTite #242.

I do the same thing on the AW4 oil sump (M6-1.0x20m/m or 25m/m) with widely-spaced studs. The crossmember gets in the way of using too many, but you really only need a few anyhow.

 

[Andy in Pa.]

I find the easiest way to re-seat the oil pan gasket is to replace every other bolt with a stud. Slip the pan up over the studs, and start tightening the nuts up until the bolts can go in.

 

[5-90]

I find the easiest way to re-seat the oil pan gasket is to replace every other bolt with a stud. Slip the pan up over the studs, and start tightening the nuts up until the bolts can go in.

True - but that's an awful lot of studs, and it can eat up space you need quickly. Recall that the front axle is in the way down there - if you're not lifted, you're due for trouble.

I find a 3" lift is about the minimum needed to make removing the oil sump easy - else you have to jack the front end up to "full droop" and force the front axle down with a bottle jack (which is usually enough for me.)

 

[ehall]

I use that copper adhesive spray, works pretty well for most things if you're quick and the pan is clean

 

[kastein]

Diff cover screws are 5/16"-18x3/4", just like the "corner" screws on the oil sump. Probably come out of the same bin at the factory, if it's a 35C.

My money's on this or an inspection cover bolt, though I don't seem to recall those being serrated.

This is on your 91 right? Looks like bolts for the inspection cover (unless I'm misreading my catalog/diagram) are 3x M8x1.25x20 2x M12x1.75x35mm (those are the big honking 18mm head ones) and 1x M8x1.25x30mm. So if they're metric, that's probably where they came from, if they're SAE I'd guess a diff cover bolt or something else. Could also be one of the bolts holding the various cable straps onto the sides of the block, IIRC those are almost all non serrated 5/16" and 3/8" bolts though. Maybe a distributor hold-down bolt (1/4-28 1.625" long, says the internet, which seems wrong to me. Part number is 6033 479 if you want to verify yourself.) The short bolt holding the oil pump to the block is a 5/16-18 that is either 3/4 or 7/8 long, not sure which, and the 4 bolts holding the cover plate onto the oil pump housing are 1/4-20 1/2" long.

It could also be any of a handful of short stubby metric bolts on top of the intake manifold holding various brackets and the fuel rail down, though I don't recall any of them looking like that.

In any case, I'd check the oil pump very carefully, make sure both the long and short bolts are present and the 4 bolts holding the cover plate on are installed, and then button it back up and forget about it.

I didn't notice any bolts like this one holding the inspection cover on, just two really small ones and two really big ones, but maybe this one is supposed to be there too. I'll have to check later tonight.

What's up with those huge 17 millimeter bolts & nuts on the inspection cover anyway? They don't seem to be doing anything the smaller machine screws aren't already doing yet they're beefy enough to be control arm bolts...

I thought they were 18mm heads? That's what I seem to recall using last time.

Either way, I believe it's because the bolt pattern for the bellhousing was originally designed for a V8 (doesn't the 4.0/258 share a bellhousing pattern with the old AMC 304/360/390/401 in '72 and later? I've been lead to believe so though I'm not certain) which could have mounting bosses much further below the crankshaft as it's a 90 degree V block instead of an inline. Either that, or they are intended to have pressed steel braces bolted to them, as the chryco V6-239, V8-318, and V8-360 have - the braces bolt to the lower bellhousing bosses as well as to the engine mount pattern and (at least on the Dakota) to the bracketry which attaches the IFS diff housing to the frame.

edit: verified bellhousing pattern is the same, '81 CJ with a 6 or 8 cylinder engine uses the same part number auto trans w/ bellhousing. Still haven't verified what the lower bolt holes are for and can't find a pic of the back of an AMC V8, but reasonably certain...

edit2: AMC V8 doesn't appear to have block skirts that go down anywhere near that low, so I'd put money on them being intended for attaching pressed brackets to hold an IFS diff and/or stiffening braces to the engine mounts, which were then never needed on the XJ.

 

[Talyn]

Coming late to the thread but it looks like it could be a timing chain cover bolt.

Its not. Size doesn't match anything on the timing cover.

 

[Red91Laredo]

I have RE 3.5" coils up front (which actually gave 4.25" of lift) so I have pretty good clearance to get the oil pan in & out. I was thinking of securing the gasket to the oil pan using gasket spray or a thin coat of RTV. Is that a good plan or would it be better to adhere the gasket to the block?