Author Topic: Pesky Oil Leak  (Read 4597 times)

Offline 78ScottsdaleK20

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Pesky Oil Leak
« on: November 21, 2006, 10:37:00 PM »
Dropped in a 350 in my 78 Scottsdale K20 w/ 4spd. Ever since dropping the motor in (4k-6k miles ago) I have had an oil leak. Most of the oil is accumilating on the passenger side of the block (underside). Starter is saturated as is the clutch. Oil drips from mostly the pass side of the pan, bellhousing, and rear of the oil pan. I have checked the oil sending unit, the rear of the motor as much as I can, replaced the valve cover gasket 4 times, intake gasket once, oil pan gasket twice...still leaks oil. I suspect its the rear main, but the motor is brand new. I have really high oil pressure-oil pressure gauge pegged both cold and hot. It may drop a little to 50-55psi when idling once warm. The motor is a 9.5:1 with Hypereuctectic flat top fed mogul pistons, speed pro RV cam with .448" lift 112 degree seperation. Stock heads. Not looking forward to replacing the rear main but might have to as my clutch wont last long...Also I have to drop my transfer case to replace a blown seal between it and the trans. Wonder if it would behoove me to just go ahead and drop the transmission (remember its a 4 spd...uugghh) and do the rear main at that time. Will it make the job that much easier...?

Thanks for any tips and advice...this site is the best!

Mike
78 Scottsdale
350 / 4spd / NP205
4 inch lift w/33's

78 Scottsdale K20
350 SM465 NP205
4" w 35's

Offline Lt.Del

  • Andy aka:SgtDel
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Re: Pesky Oil Leak
« Reply #1 on: November 21, 2006, 11:05:00 PM »
I believe your worst thoughts are true.....three words....rear main seal.  Just because it is new really doesn't matter.  I know when i replaced mine on my stroker 383, I didn't have to remove the transmission (however it was an automatic--not sure if it makes a difference with a 4spd.--probably not ).

Take a dry rag and a flashlight and look up under the truck while it is idling...with wheels blocked (just in case) and just look all around your oil pan....wipe excess oil off and watch.  If it seems to come from around the flywheel, yep, rear main.  

If it is your rear main, it only takes a couple of hours, just wear some old clothes because oil will get EVERYWHERE as it drips from the crank.  Hint:  take oil out of the pan a couple of hours prior to taking pan off.

 
















SgtDel
aka "Andy"

www.delbridge.net

1979 Big 10 383 stroker
1991 Blu 'Burb 3/4 ton 4x4

Edited by: SgtDel  at: 11/21/06 11:18 pm

Offline ChevyGuy

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  • Posts: 268
Re: Pesky Oil Leak
« Reply #2 on: November 22, 2006, 01:09:00 AM »
Do you have a pcv valve hooked up and another hose looping from the other valve cover? sounds like to much crankcase pressure or a high volume high pressure pump.


Offline 78ScottsdaleK20

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Pesky Oil Leak
« Reply #3 on: November 22, 2006, 12:56:00 PM »
Thanks for the tips Andy. I have done this before to my old motor (without any luck it continued to leak after the rear main was replaced.) I do have a PCV valve located on the driver side valve cover hosed into the front of the carb. I have a breather on the pass. side of the valve cover.

Well I think i will be spending some time underneath the truck this weekend trying to stay dry in the rain between Turkey sandwiches. Have two seals to replace. 1. Seal between the transmission and transfer case (kinda like the rear main) 2. Rear main seal.

Thanks for the replies guys Happy Thanksgiving!
Mike
78 Scottsdale K20
350 / 4 spd / NP205
4" lift w / 33's

78 Scottsdale K20
350 SM465 NP205
4" w 35's

Offline cruppert77

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Re: Pesky Oil Leak
« Reply #4 on: November 22, 2006, 02:46:00 PM »
Had the same thing happen to my 383 when I put it in. Sorry to hear about your luck. Happy Thanksgiving.


Offline thirstycanadian

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  • Posts: 26
oil pan
« Reply #5 on: November 22, 2006, 09:34:00 PM »
have any of you guys had trouble removing your oil pans?  I have read in my repair manual that on some of these trucks you have to remove the engine mounts and jack up the engine a little to get the pan to clear that crossmember.  Has anyone had to do this?   Since I do not have a jack on hand other than the one in the truck, I do not want to break the seal on the pan only to find out that I cannot get it off.

Specifically, mine is a 454 in a 1 ton 4x4, with an oil leak that can be impressive at times.