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oil pan gasket installation


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I'm trying to properly reinstall the oil pan on my '72 Z, and I'm getting conflicting advice. I have read some previous threads on this site from 2005, but questions remain. The engine was just rebuilt by a "pro", yet the new cork gasket he installed (with apparently some form of black silicone sealer, too), did not prevent leaking along the rear edge on the right side of the block. I found all 31 bolts to be quite loose, so I torqued them to about 3 ft./lbs (two of my manuals suggested anywhere from 3-7 ft./lbs for pan bolts),. The leaking continued, and the gasket material actually started to spread and split. After removing the pan, I found the gasket to be completely shot.

 

I have a new Fel-Pro gasket, and I want to install it properly. Fel-Pro's instructions call for a gasket adhesive and a silicone sealant, but no specific brand is mentioned. Previous threads have suggested using Copper spray to keep the gasket in place, or nothing at all. The pan seems true enough, but the flange immediately surrounding each bolt hole does seem to have a slight flare toward the engine block. Is this distortion, or is the pan made this way to firmly engage the gasket material? Previous threads indicate I should probably flatten the area around each bolt hole?

 

It also sounds as though oil leakage can occur from the two square plugs that fit into the rear main cap. Where exactly are these caps? Are they easily accessible with the oil pan off?

 

Specific advice on how to proceed would be greatly appreciated! Thanks.

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First, there must be a twist in the pan to cause the leak. Second, the cork gasket will disintegrate immediately if you remove the oil pan and he installed some black silicone adhesive.

 

Make REAL SURE that that the pan is FLAT and that the sealing area has no gouges in it from previous removals. Install a new gasket with simple hi-tack gasket dressing to hold it in place. DON'T USE SILICONE because you don't want to glue the basket material in place and that most people with a leak will glob on way too much and it will pinch off inside the pan when compressed and end up in the oil strainer!

 

Nothing is "wrong" with using a cork gasket. All it has to do is prevent oil from sloshing out of the pan; it's not even under any pressure. If the leak was that severe, why not take it back to the guy that just rebuilt it and have him correct it?

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yeah, maybe have the guy who messed it up fix it... the cork gasket is supposed to expand a little when oil gets on it. Some people say to use the silicone, but I've always had leaks from that. You might do like he said above use some hi tack dressing to hold it in place. The kind I've had good luck with looks sorta like thin molassis, very sticky stuff, but seals well.

 

Make sure both your block and your pan are clean and smooth, you'll need to flatten those dimpled bolt holes. as for the square caps, I'd have to look at my manual again. I don't remember them. it's been a few years since I did a pan though. While your pan is out, you might as well clean it up and paint the OUTside. I used a drill with a 10mm adapter to help me get all the bolts out and back in, then torqued to about 7lbs or so. Haven't had a leak in 3 years now.

 

Phar

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without a doubt, the biggest single thing to do to keep it from leaking is to flatten out the dimpled holes. Later cars had a thick metal strip that went between the pan and the bolts, around the rear of the pan, and if you have this piece you need to make sure it's flat too. Once some gorilla overtightens those pan bolts and dimples and deforms the pan, it is impossible to get the even, uniform light pressure on the gasket that you need. And when you reinstall your pan, don't be a gorilla. If the pan leaks, overtightening it will not help, it will just re-dimple it. To get the dimples out, don't just hit them with a hammer, you must back them with a "dolly"...something hard, flat, and at least three times as heavy as the hammer.

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I always use that copper gasket spray on the pan side and leave the block side dry so I have the option to remove the front cover later if I have to. I have had bad experiences with using any type of RTV other than the spray on the oil pan gasket.

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You should never use a sealer with a cork gasket. Just lightly oil it on both sides prior to installation. With fiber gaskets I would use some sealant. Just make sure to use it sparingly and not have it squeeze into the pan. Also, do NOT over tighten your bolts. It also helps to go around and tighten each one a little bit at a time.

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Thanks for all the input. A long-time friend, but GERMAN car mechanic, has checked my oil pan, and we agree that the bolt holes are dimpled. So, I've got some hammer and dolly work to do on that. Opinions are still all over the map re: what type of sealer/adhesive to use, if any, when reinstalling the pan and Fel-Pro gasket, but a number of votes have been in favor of a simple sticky "Hi-tack" product, like Permatex makes. Definitely avoiding any silicone products.

 

Torquing the pan bolts seems like a "black art". Torque settings of anywhere from 1-7 ft/lbs have been mentioned. The last suggestion was to not even use a torque wrench, but slowly tighten the bolts by hand in a sequential pattern, watching for the gasket to begin to displace around the sides of the pan. How's that for precise?

 

I finally figured out what the rear main cap side plugs are. They are two elongated rubber plugs, about 1.5" long, with a very small rectangular profile. They seem to be "captured" within the pan gasket area, so I'm not sure how they would cause a leak by themselves. But, I did remove one of the plugs, and it came out pretty easily with a needlenose pliers. Does this mean I should replace both plugs with new ones, or can I get by with applying some form of sealant to the plugs and reinstalling them? I'm not really too interested in trying to remove the main cap itself to reapply sealant as directed in the Service Manual. What type of sealant should I use? My manuals only refer to using a "jointing compound", whatever that means. Any specific suggestions here?

 

Thanks again for your help.

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