283 Oil Leak? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

66gmckid123 · 10-01-2008, 06:55 PM

Hey I've been lurking the site for a while, but haven't made any posts yet. I have a 66gmc fleetside, 283 out of a 61 impala. I have an oil leak here's whats been replaced valve covers, intake (siliconed the ends), oil pan, oil pressure switch, and distributor ring. The oil runs down the side of the bellhousing and runs from under the crossmember and drips out the inspection cover. The back top of the engine looks a little wet like the oil breather is leaking, is that possible? I thought rear main, which it could still be but it's running down the side of the bellhousing and drips down from the back of the motor? Any thoughts would be much appreciated
Thanks Andrew

283 Man · 10-01-2008, 07:03 PM

Welcome to the forum!! check your value cover gaskets and your pans that cover your heads.I had a pair of crome value covers on my 283 that leaked the same way needless to say took them off not useing them any more.

**Corts60** · 10-01-2008, 08:19 PM

Also, where is your crankcase breather? Are you running a PCV valve or is that early '61 a "road draft" type ventilation? If it is coming out of the breather than there is too much crankcase pressure...

fchava · 10-01-2008, 09:03 PM

Quote:

Originally Posted by Corts60

Also, where is your crankcase breather? Are you running a PCV valve or is that early '61 a "road draft" type ventilation? If it is coming out of the breather than there is too much crankcase pressure...

I agree with corts60 also check your oil pressure sending unit or oil pressure fitting if using a mechanical gauge

66gmckid123 · 10-01-2008, 09:11 PM

I'm using the road draft ventilation system. I have replaced the valve covers gaskets twice, first rubber, and then cork (siliconed too). I looked at the valve cover gaskets from underneath and they didn't seem wet. The oil pressure switch is a new mechanical one, which isn't leaking. Oh yeah and the oil pan gasket has been replaced. The oil just runs off each side of the bellhousing so I don't know. Maybe I didn't silicone the intake enough?

Fred T · 10-02-2008, 09:58 PM

You need an inspection mirror to look at the rear of the engine.

There mainly 3 places it could be leaking. The valve covers, the oil sending unit and the end of the intake manifold.

I am not a fan of RTV on valve cover gaskets. With cork I use yellow weatherstrip adhesive on the cover side. With the good rubber gaskets no sealant is required, but they are a pain to get lined up right. If the covers are sheet metal they need to have the flanges straight and don't over-tighten the bolts.

You didn't say if you had the intake off. If that's what leaks, you need a 1/4" bead of sealant on the ends. And check with a mirror while the sealant is wet so you can pull it off to fix it.

protrash64 · 10-02-2008, 10:13 PM

I like Fred T's info...about the valve covers, I will only use cast covers with steel/rubber gaskets. I have had no issues and they can be removed many times w/out damage.

soba_03 · 10-06-2008, 09:52 AM

Only thing I might add is look at your oil dipstick tube as well. Maybe bent or pulled up out of the block even cracked which will allow some oil out as well..YES definately cast valve covers with rubber seal IS the only way to go.....

10-01-2008, 06:55 PM	#1
66gmckid123 Registered User Join Date: Jul 2008 Location: Shoreline, WA Posts: 26	283 Oil Leak? Hey I've been lurking the site for a while, but haven't made any posts yet. I have a 66gmc fleetside, 283 out of a 61 impala. I have an oil leak here's whats been replaced valve covers, intake (siliconed the ends), oil pan, oil pressure switch, and distributor ring. The oil runs down the side of the bellhousing and runs from under the crossmember and drips out the inspection cover. The back top of the engine looks a little wet like the oil breather is leaking, is that possible? I thought rear main, which it could still be but it's running down the side of the bellhousing and drips down from the back of the motor? Any thoughts would be much appreciated Thanks Andrew

10-01-2008, 07:03 PM	#2
283 Man Registered User Join Date: Apr 2007 Location: Jane,Missouri Posts: 844	Re: 283 Oil Leak? Welcome to the forum!! check your value cover gaskets and your pans that cover your heads.I had a pair of crome value covers on my 283 that leaked the same way needless to say took them off not useing them any more.

10-01-2008, 08:19 PM	#3
Corts60 Just here to tinker Join Date: Jun 2008 Location: Holland, MI Posts: 3,697	Re: 283 Oil Leak? Also, where is your crankcase breather? Are you running a PCV valve or is that early '61 a "road draft" type ventilation? If it is coming out of the breather than there is too much crankcase pressure... __________________ 78 C10 SWB Diesel #1 (wrecked)http://67-72chevytrucks.com/vboard/s...1978+silverado 78 C10 SWB Diesel #2 (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=650751 60 GMC Suburban (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=445526 60 GMC 1000 (sold)http://67-72chevytrucks.com/vboard/showthread.php?t=298235 67 GMC 1500 (sold) http://67-72chevytrucks.com/vboard/s...d.php?t=803695 73 Chevy C20(Daily)http://67-72chevytrucks.com/vboard/s...d.php?t=852767 86 Suburban(summer unit) http://67-72chevytrucks.com/vboard/s...d.php?t=810697 88 Suburban 4x4(sold)

10-01-2008, 09:11 PM	#5
66gmckid123 Registered User Join Date: Jul 2008 Location: Shoreline, WA Posts: 26	Re: 283 Oil Leak? I'm using the road draft ventilation system. I have replaced the valve covers gaskets twice, first rubber, and then cork (siliconed too). I looked at the valve cover gaskets from underneath and they didn't seem wet. The oil pressure switch is a new mechanical one, which isn't leaking. Oh yeah and the oil pan gasket has been replaced. The oil just runs off each side of the bellhousing so I don't know. Maybe I didn't silicone the intake enough?

10-02-2008, 09:58 PM	#6
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	Re: 283 Oil Leak? You need an inspection mirror to look at the rear of the engine. There mainly 3 places it could be leaking. The valve covers, the oil sending unit and the end of the intake manifold. I am not a fan of RTV on valve cover gaskets. With cork I use yellow weatherstrip adhesive on the cover side. With the good rubber gaskets no sealant is required, but they are a pain to get lined up right. If the covers are sheet metal they need to have the flanges straight and don't over-tighten the bolts. You didn't say if you had the intake off. If that's what leaks, you need a 1/4" bead of sealant on the ends. And check with a mirror while the sealant is wet so you can pull it off to fix it. __________________ Fred There is no such thing as too much cam...just not enough engine.

10-02-2008, 10:13 PM	#7
protrash64 Resistance is Futile Join Date: Dec 2006 Location: Mesa,Arizona Posts: 3,520	Re: 283 Oil Leak? I like Fred T's info...about the valve covers, I will only use cast covers with steel/rubber gaskets. I have had no issues and they can be removed many times w/out damage. __________________ 64 CHEVY PICK-UP > http://67-72chevytrucks.com/vboard/s...otrash+re-hash 64 CARRYALL >http://67-72chevytrucks.com/vboard/s...=1964+suburban 66 LB >http://67-72chevytrucks.com/vboard/s...d.php?t=427852 STRENGTH/DETERMINATION/MERCILESS/FOREVER .......posted via stationary device

10-06-2008, 09:52 AM	#8
soba_03 Registered User Join Date: Sep 2007 Location: Fairdale, Kentucky Posts: 560	Re: 283 Oil Leak? Only thing I might add is look at your oil dipstick tube as well. Maybe bent or pulled up out of the block even cracked which will allow some oil out as well..YES definately cast valve covers with rubber seal IS the only way to go.....



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