# chevy 350 rear main seal leak (new seal) **URL:** \ **Category:** NYSpeed Automotive\ **Created:** [August 26, 2010, 7:02pm UTC](https://forums.speedlife.net/t/chevy-350-rear-main-seal-leak-new-seal/159582 "2010-08-26T19:02:09Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Camaro079](https://avatars.discourse-cdn.com/v4/letter/c/d6d6ee/32.png) [@Camaro079](https://forums.speedlife.net/u/Camaro079)\ **Post date:** [August 26, 2010, 7:02pm UTC](https://forums.speedlife.net/t/chevy-350-rear-main-seal-leak-new-seal/159582/1 "2010-08-26T19:02:09Z")
i built a 1970 350 (30 over) at school (4 yrs ago), finally getting it running, working the bugs out etc…had it on a test stand and i was leaking oil from the back, either the pan seal or rear main seal. so i reinstalled the pan gasket and same thing. so i changed the rear main seal( being sure to follow direction explicitly), the oil pan gasket, and the oil pan( i had a spare anyway)…ran for about half an hour no problems, but the motor started to get alittle warm (i think my timing was wrong), it got up to about 225 degrees (and i shut it off-leaving the radiator fan running to cool it down), and i noticed dripping from the back of the motor. so did i melt the seal? or did it just take that long to leak reguardless of temp? thanks for your thoughts…i’m just wondering if i did something wrong on install or if temp would really play that much into it. ---
**Author:** ![Karter](https://avatars.discourse-cdn.com/v4/letter/k/e480ec/32.png) [@Karter](https://forums.speedlife.net/u/Karter)\ **Post date:** [August 26, 2010, 9:04pm UTC](https://forums.speedlife.net/t/chevy-350-rear-main-seal-leak-new-seal/159582/2 "2010-08-26T21:04:13Z")
you put it in wrong or you used the wrong seal. 225 wont hurt the seal. I spun the bearings in a stock car motor, burried the temp gauge until it seized trying to keep points, didnt hurt any seals, not even a HG ---
**Author:** ![Pauly](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/pauly/32/7493_2.png) [@Pauly](https://forums.speedlife.net/u/Pauly)\ **Post date:** [August 27, 2010, 1:38pm UTC](https://forums.speedlife.net/t/chevy-350-rear-main-seal-leak-new-seal/159582/3 "2010-08-27T13:38:40Z")
yeah somethings wrong there check the crank for any ridge/damage ---
**Author:** ![Spam16v](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/spam16v/32/5287_2.png) [@Spam16v](https://forums.speedlife.net/u/Spam16v)\ **Post date:** [August 27, 2010, 5:50pm UTC](https://forums.speedlife.net/t/chevy-350-rear-main-seal-leak-new-seal/159582/4 "2010-08-27T17:50:02Z")
felpro 1pc pan gasket FTW too. dab of RTV under the corners of the rear main cap, and make sure the pan’s not all mangled causing the leak. ---
**Author:** ![Karter](https://avatars.discourse-cdn.com/v4/letter/k/e480ec/32.png) [@Karter](https://forums.speedlife.net/u/Karter)\ **Post date:** [August 27, 2010, 6:37pm UTC](https://forums.speedlife.net/t/chevy-350-rear-main-seal-leak-new-seal/159582/5 "2010-08-27T18:37:01Z")
if its a chrome pan, throw it away and buy a stock pan ---
**Author:** ![challengermike](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/challengermike/32/5106_2.png) [@challengermike](https://forums.speedlife.net/u/challengermike)\ **Post date:** [August 27, 2010, 7:31pm UTC](https://forums.speedlife.net/t/chevy-350-rear-main-seal-leak-new-seal/159582/6 "2010-08-27T19:31:35Z")
i agree with pauly,theres probably a groove or a nick in the crank or rust pits. ---
**Author:** ![Camaro079](https://avatars.discourse-cdn.com/v4/letter/c/d6d6ee/32.png) [@Camaro079](https://forums.speedlife.net/u/Camaro079)\ **Post date:** [August 29, 2010, 8:31pm UTC](https://forums.speedlife.net/t/chevy-350-rear-main-seal-leak-new-seal/159582/7 "2010-08-29T20:31:02Z")
thanks for the help. yeah the first pan i tried was chrome so i’ll ditch that one. i’ll have to check the crank. it shouldnt have any issues, it was a reconditioned crank, but i’ll check anyway.