oil leak suggestions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Benrs86 · 05-20-2003, 11:52 PM

ive had this oil leak for a while and finally drove me insane. its a smallblock 350. the leak is on the lower half (not valve covers or back of intake). today after school i pulled the engine out, and took the oil pan off. the rear rubber gasket was sealed good, but part of the cork one looked like it could have been leaking. do i just put new gaskets there or should i put a new rear main seal while its out? it was 3 years ago now that i rebuilt that motor and cant remember how that seal works. i would have to take all the caps off and lift the crank out a little or how would i do that? thanks, Ben

Bowed · 05-21-2003, 12:29 AM

If the rear seal was replaced 3 years ago it should be alright but then again it might be a good idea to replace it just to be on the safe side seeing the engine is out any way . If you remove the rear bearing cap the lower half of the seal comes out with it and and then just work the other half of the seal out with some thing small and blunt so you do not damage any surfaces. Then work in the new top half ( carefuly ) and assemble the rest and you do not have to touch the crankshaft . On the oil pan gasket it might be best to use a one piece rubber gasket , a little more expense but better . Good luck .

cdowns · 05-21-2003, 12:44 AM

most good auto parts stores have an inexpensive tool kit for removing and replacing the main seals like he said just taking off the main cap slide the old one out and the new one in

jimfulco · 05-21-2003, 02:57 AM

If you use cork gaskets next time, retighten them after a few months. Cork gaskets tend to loosen a little due to shrinkage. Usually they need a quarter-turn or so. Just don't over-tighten them to where the cork pinches apart. Same goes for valve covers.

TROYLV · 05-21-2003, 08:22 AM

another trick i use on the two peice rear seal is to leave the ends about a 1/4 to1/8 inch offset from where the bearing cap mates up to the block. this stagers the seal in relation to that line and helps prevent a leak. if you need a pic let me know. troylv@lvcm.com

Benrs86 · 05-21-2003, 11:20 AM

thanks a lot, i might go return the cork one i bought for a one peice rubber and then get a seal. TROY i think i get what you mean, like twist both halves of the seal a little so the cab lines and the seal lines are offset. if i get a rubber seal i still use rtv silicone right? thanks a lot, Ben

theo70 · 05-21-2003, 04:36 PM

I would recommend Fel-Pro's one piece gasket. Hasn't failed me yet.

**old Rusty C10** · 05-21-2003, 04:39 PM

after hesitating to try the one piece gaskets i now swear by them they make life so much esier

**68 Stepside** · 05-21-2003, 07:09 PM

I'm with the rest of the guys on the one piece rubber gaskets. I swear by them now too. Felpro's is nice too, comes with new, longer bolts and everything.

05-20-2003, 11:52 PM	#1
Benrs86 Registered User Join Date: Feb 2000 Location: Brandon, SD, USA Posts: 1,292	oil leak suggestions ive had this oil leak for a while and finally drove me insane. its a smallblock 350. the leak is on the lower half (not valve covers or back of intake). today after school i pulled the engine out, and took the oil pan off. the rear rubber gasket was sealed good, but part of the cork one looked like it could have been leaking. do i just put new gaskets there or should i put a new rear main seal while its out? it was 3 years ago now that i rebuilt that motor and cant remember how that seal works. i would have to take all the caps off and lift the crank out a little or how would i do that? thanks, Ben __________________ Brandon, SD 69 GMC 1/2 ton 2wd wide long bed with wood 3 on the tree 350 engine 4 bolt main rv cam AIM = Alphray04

05-21-2003, 12:29 AM	#2
Bowed Registered User Join Date: Oct 2002 Location: where it's hot Posts: 1,059	If the rear seal was replaced 3 years ago it should be alright but then again it might be a good idea to replace it just to be on the safe side seeing the engine is out any way . If you remove the rear bearing cap the lower half of the seal comes out with it and and then just work the other half of the seal out with some thing small and blunt so you do not damage any surfaces. Then work in the new top half ( carefuly ) and assemble the rest and you do not have to touch the crankshaft . On the oil pan gasket it might be best to use a one piece rubber gasket , a little more expense but better . Good luck . Last edited by Bowed; 05-21-2003 at 12:38 AM.

05-21-2003, 12:44 AM	#3
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	most good auto parts stores have an inexpensive tool kit for removing and replacing the main seals like he said just taking off the main cap slide the old one out and the new one in __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

05-21-2003, 08:22 AM	#5
TROYLV Registered User Join Date: Oct 2002 Location: LAS VEGAS, NV. Posts: 157	rear seal another trick i use on the two peice rear seal is to leave the ends about a 1/4 to1/8 inch offset from where the bearing cap mates up to the block. this stagers the seal in relation to that line and helps prevent a leak. if you need a pic let me know. troylv@lvcm.com __________________ troy wilson

05-21-2003, 11:20 AM	#6
Benrs86 Registered User Join Date: Feb 2000 Location: Brandon, SD, USA Posts: 1,292	thanks a lot, i might go return the cork one i bought for a one peice rubber and then get a seal. TROY i think i get what you mean, like twist both halves of the seal a little so the cab lines and the seal lines are offset. if i get a rubber seal i still use rtv silicone right? thanks a lot, Ben __________________ Brandon, SD 69 GMC 1/2 ton 2wd wide long bed with wood 3 on the tree 350 engine 4 bolt main rv cam AIM = Alphray04

05-21-2003, 02:57 AM	#4
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	If you use cork gaskets next time, retighten them after a few months. Cork gaskets tend to loosen a little due to shrinkage. Usually they need a quarter-turn or so. Just don't over-tighten them to where the cork pinches apart. Same goes for valve covers.

05-21-2003, 04:36 PM	#7
theo70 COMING SOON... Join Date: Feb 2003 Location: Ft Worth TX Posts: 406	I would recommend Fel-Pro's one piece gasket. Hasn't failed me yet.

05-21-2003, 04:39 PM	#8
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,310	after hesitating to try the one piece gaskets i now swear by them they make life so much esier __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

05-21-2003, 07:09 PM	#9
68 Stepside huh? Join Date: May 2000 Location: Washington, Illinois Posts: 5,690	I'm with the rest of the guys on the one piece rubber gaskets. I swear by them now too. Felpro's is nice too, comes with new, longer bolts and everything. __________________ Someday when I'm lonely, Wishing you weren't so far away, Then I will remember Things we said today. RIP El Jay

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