replace oil pan gasket

I have an aviad oil pan 351 w. the rear of the pan was leaking. Replaced it with a a one piece ford gasket. it previously had the 4 piece cork gasket. I coated all surfaces with black silicone. button it all up torgue to 15 lbs. still have a leak at the rear of the pan where the curved section goes arround the rear main. I want to stop this leak makes a mess, Is the secret more silicone. any tips would be appreciated

LLoyd
 
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First..check it is the pan & not the rear main seal....dry off the rear face of the #5 cap & pan and then run motor while watching for the first drop of oil, if it only comes from the pan fine, but if its evident on the cap rear face its the seal or even higher up- gallery plugs, cam plug, valley etc.
Early blocks had pin in seal groove of cap to prevent rope seal from spinning, this must be removed for 2 piece rubber seal. If this has been removed & the remaining hole not blocked off it could be the source of your leak .
 

Randy V

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I have an aviad oil pan 351 w. the rear of the pan was leaking. Replaced it with a a one piece ford gasket. it previously had the 4 piece cork gasket. I coated all surfaces with black silicone. button it all up torgue to 15 lbs. still have a leak at the rear of the pan where the curved section goes arround the rear main. I want to stop this leak makes a mess, Is the secret more silicone. any tips would be appreciated

LLoyd

RTV silicone will make gaskets slip in many cases and not seal properly..

I use this stuff in the corners with a thin film of it on the oil pan where it contacts the front and rear of the gasket (over the hump)...

http://www.permatex.com/products/Au...uto_Permatex_the_Right_Stuff_Gasket_Maker.htm

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If all your surfaces are super clean (I use lacquer thinner) to start with and you let this stuff cure for 6-8 hours before putting it to work - I've not yet had a leaker...
 
Randy's right on. Right Stuff is great gasket sealant.

RTV can (especially when not cured fully) promote leaks, and also get into the oil supply if applied liberally to the point where it drools down on the inside face. I always cringe when taking an engine apart and I see that it was assembled with lots of RTV (obviously, I'm not a fan of RTV). Others use it however, and give it good reviews.

I happen to use permatex aviation gasket sealant stuff called form-a-gasket. Great stuff too. Like Randy says, get both metal faces absolutely dry and clean. I usually only put sealant on the face of the part which attaches to the engine (so the part and the gasket come off cleanly later on) and leave the other face dry.

Never had a leak.
 

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Ok guys the right stuff it is. Ja i remember seeing the hole you are talking about inthe grove where the gasket rides i put a pin in it and it was open. how do you seal it?

LLoyd
 
Ok guys the right stuff it is. Ja i remember seeing the hole you are talking about inthe grove where the gasket rides i put a pin in it and it was open. how do you seal it?

LLoyd

Clean & dry the hole out and the just push a bit of 'Right Stuff' into the hole before you refit the gasket & pan.

Could still be an issue with the rear main seal bottom half though as it has a rib that could possibly intersect with that hole & still leak slightly. That might depend on whether you or whoever assembled the motor used a small amount of sealant to OD of seal halves.

The correct way if you think this is a possible is remove the rear main cap, block that hole with a bit of alloy rod or epoxy & then reassemble.
 
thanks for all the good advice. this is getting expensive with 8 quarts of syn oil gasket and whole lot of time. I just hate leaks. Is everyone in agreement with the one piece gasket as opposed to the 4 piece cork. I think working against gravity 4 pieces would be a nightmare. I bought a stud bolt kit thinking that will help with the alignment and holding the gasket in place while i slide the pan on.
i'll let you know if i'm jumping with glee or on a big sword.

Lloyd
 

Randy V

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Lloyd, I much prefer the one piece gasket over the other - even though the price is substantially higher.

Why not just drain the oil you have into a clean pan and reinstall it in the engine when done?
 
Loyd I just helped a fellow eliminate pesky leaks in his Cobra that sports a Milodon pan with a 351 Windsor. He had been using 4 piece gaskets and silicone. Get a Felpro 1 piece gasket (Blue) that has the metal rib down both sides that prevents overtightening of the gasket. Use "The Right Stuff" in the corners and put a small bead around each bolt hole and on the surface where the pan goes over the main caps. Let it set overnight before filling with oil. You'll never go back to silicone.
 
i under estimated my skill. the pan was not the source of the leak. its the rear main. the pan serfaces were all bone dry. This is a hand built racing engine thats gets driven very little. The engine was built in 2004. so i'm sure its a neoprene seal.
how much of a job is it to pull the rear main and change the seal?????
the other option is to button it up put in a seal conditioner
lastly just let it leak all summer and fix it next winter down time.
So if you guys with any experience with changing the rear seal in the car chkme in here

LLoyd
 
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Since you have the small pin hole its fairly likely that it already has the 2 piece rubber seals, these can 'stick' to the crank and fail early in life if they are left to sit for some time between assy & startup if assembled with only oil on the seal surface- a light coating of grease on the crank surface usually prevents this. It can be replaced 'in situ'-- just takes some care & patience to feed the top half in while preventing it from damage on its 'OD' @ the cap/block surface---remember to get it facing the right way also, these seal halves have a 'front/rear' orientation.

Attached dwg should help.. You might have to enlarge it to 200% to read text, I am still stuffing something up on this dwg program..:sad:...:)
 
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two years between assy and startup. i read somewhere about putting sealer on cap arround where the seal is to prevent leaks throught the joint
after research on the internet it doesnt sound difficult. 96-105 lbs torque 3 stages
it has always leaked it just got worst this season.
thanks for the info
Lloyd
 
i read somewhere about putting sealer on cap arround where the seal is to prevent leaks throught the joint

Lloyd

I wouldnt put any on the top half, it could make fitting it a problem in your situation & removal in the future an issue also, a small amount on the bottom half might help along with a smear on the cap/block interface, but just a smear, any on the sealing surface of the seal halves could undo all your good work..:)... and dont forget a light smear of grease on the seal lip/crank seal area will help the fitting process.
 
pull the rear main to see the seal. I'm sure this is my problem. It was highly pitted. The leading edge of the seal was pitted as well. it was actually easy to change. i have everything buttoned up. i'll let it sit overnight and fill it with oil tommorrow, I'm keeping my fingers crossed no leaks

Jac thanks for your input

LLoyd
 
Success. Anyone contemplating changing that two piece seal. Go for it. Very easy to do. first time in 4 years it hasn't left an oil spot whereever i parked it.

I think if you were going to change the pan gasket change that rear seal as precaution
Jac thanks for your help

LLoyd
 
I pulled my pan twice before realizing it was the rear main seal. I could not believe the rear main seal was leaking on a new rebuild. Replaced the standard black rubber seal with a felpro performance 2 piece seal. Cocked the seal so the edges did not line up with cap and block. Used a little dab of the Right Stuff on the seal edges and the edge of the cap (Haines Manual). I have a Canton pan and used a Moroso 4 piece seal. The best sealer is the Ford grey gasket sealer used for diesel engins. $23 for a small tube that you use with a calking gun. Used a couple of studs to line up the pan and gaskets. It is dry as a bone.
 
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