drip, drip, drip: oil leak
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Joined: Apr 2005
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drip, drip, drip: oil leak
My L46 1970 350 is leaking from the oil pan / timing cover gasket area.
I rebuilt the motor last winter and used a standard cork / rubber 4piece set.
After about 300 miles, it started leaking. So I bought a $40 Felpro one-piece gasket. Still leaks.
So I bought a new GM timing chain cover, because the old one looked a little beat up on the flange. Still leaks.
So I took a hammer and a piece of wood and gingerly lessened the gap between the timing chain cover lip and the oil pan lip. Still leaks.
So I have looked for a new oil pan for my motor, but they no longer make them: it's a 5-quart, left side dipstick, small sized gasket front.
I don't want to put anything but an original correct pan on it.
So if you have a used one or know someone who does, I'm buying !
I rebuilt the motor last winter and used a standard cork / rubber 4piece set.
After about 300 miles, it started leaking. So I bought a $40 Felpro one-piece gasket. Still leaks.
So I bought a new GM timing chain cover, because the old one looked a little beat up on the flange. Still leaks.
So I took a hammer and a piece of wood and gingerly lessened the gap between the timing chain cover lip and the oil pan lip. Still leaks.
So I have looked for a new oil pan for my motor, but they no longer make them: it's a 5-quart, left side dipstick, small sized gasket front.
I don't want to put anything but an original correct pan on it.
So if you have a used one or know someone who does, I'm buying !
Last edited by AirTrafficController; Aug 14, 2006 at 04:22 PM.
Racer
Joined: Dec 2005
Posts: 368
Likes: 4
From: . New Zealand
SBC Pan oil leaks can be caused by more than one fault.
The most bizzarre leakage path, which caused the previous owners sale of the Vette I now own, is a 3/8" bolt hole which accesses the fuel pump pushrod cavity, which also has a path to the inside crankcase. This is located on the front of the engine to the passenger side of the balancer the upper most, which should have a bolt in it, seemingly attaching nothing. In all of my years of SBC experience, this is the usual cause of front engine leaks, especially in rebuilt engines, because the installers leave it out.
Another cause is the big timing cover seal sump to small seal.
Also, hows the timing cover balancer seal, these can leak and look as though its leaking from the sump.
The most bizzarre leakage path, which caused the previous owners sale of the Vette I now own, is a 3/8" bolt hole which accesses the fuel pump pushrod cavity, which also has a path to the inside crankcase. This is located on the front of the engine to the passenger side of the balancer the upper most, which should have a bolt in it, seemingly attaching nothing. In all of my years of SBC experience, this is the usual cause of front engine leaks, especially in rebuilt engines, because the installers leave it out.
Another cause is the big timing cover seal sump to small seal.
Also, hows the timing cover balancer seal, these can leak and look as though its leaking from the sump.
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Joined: Apr 2005
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Originally Posted by Thmprr
SBC Pan oil leaks can be caused by more than one fault.
The most bizzarre leakage path, which caused the previous owners sale of the Vette I now own, is a 3/8" bolt hole which accesses the fuel pump pushrod cavity, which also has a path to the inside crankcase. This is located on the front of the engine to the passenger side of the balancer the upper most, which should have a bolt in it, seemingly attaching nothing. In all of my years of SBC experience, this is the usual cause of front engine leaks, especially in rebuilt engines, because the installers leave it out.
Another cause is the big timing cover seal sump to small seal.
Also, hows the timing cover balancer seal, these can leak and look as though its leaking from the sump.
The most bizzarre leakage path, which caused the previous owners sale of the Vette I now own, is a 3/8" bolt hole which accesses the fuel pump pushrod cavity, which also has a path to the inside crankcase. This is located on the front of the engine to the passenger side of the balancer the upper most, which should have a bolt in it, seemingly attaching nothing. In all of my years of SBC experience, this is the usual cause of front engine leaks, especially in rebuilt engines, because the installers leave it out.
Another cause is the big timing cover seal sump to small seal.
Also, hows the timing cover balancer seal, these can leak and look as though its leaking from the sump.
The crankshaft seal is fine; in fact it's brand new. I can lay under the car while it's running and watch oil drip from the lip area. I know about those bolts in the front of the motor, and they're dry and fine. It's definitely leaking from somewhere between the left front oil pan bolt (if you're looking at it from the front) down to the center of the oil pan / timing cover gap. The rush of air from the fan causes it to splatter all on the left side of the motor (looking from front). I'm at a loss on what to do, other than take the pan off for the 3rd time and caulk the heck out of it and re-install it. I've never had this much trouble with such a "minor" thing! Mark
Racer
Joined: Dec 2005
Posts: 368
Likes: 4
From: . New Zealand
Apology in advance if this sounds like I'm stating the obvious, but when you fitted the one pc sump gasket, did you put sealant or weather stripping adhesive in the timing cover channel, and a dab of RTV in the corners?
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Originally Posted by Thmprr
Apology in advance if this sounds like I'm stating the obvious, but when you fitted the one pc sump gasket, did you put sealant or weather stripping adhesive in the timing cover channel, and a dab of RTV in the corners?
I only put red RTV sealant in the corners, as per instructions. They were explicit that if you did any different, it might leak. I think I'll take your advice and load up the timing cover channel. Stay tuned
Racer
Joined: Mar 2006
Posts: 366
Likes: 1
From: Houston Texas
Hi ATC
I chased down one of these non-obvious leaks in the front that was coming from the corner of my intake manifold. The oil would run down the seam between the head and the block, and re-appear as if from the timing chain cover down at the pan.
A little bead of black rtv at the manifold and my garage floor is now dry.
I chased down one of these non-obvious leaks in the front that was coming from the corner of my intake manifold. The oil would run down the seam between the head and the block, and re-appear as if from the timing chain cover down at the pan.
A little bead of black rtv at the manifold and my garage floor is now dry.
Melting Slicks
Joined: Jul 2002
Posts: 3,128
Likes: 3
From: Deltona (son of Deland and DAYTONA) FL
i had the same exact leak last year. I thought I'd do it right by using a new timing cover and oil pan. Both looked to be original and the lips were far from straight. After 2 of those 1-piece Felpro gaskets, I STILL had a leak.
It turned out that the leak was coming from the new timing cover between the u-shaped lip that the front of the seal fits in and the timing cover itself. I reused the original pan and timing cover (as crummy as they looked) with a 3rd 1-piece seal and the leak stopped.
If your original timing cover is leaking, try a matched set from GM, or a reputible aftermarket company like Miloden, Edelbrock, or Moroso.
My guess is a high quality timing cover will fix it, but with the trouble you're having, I'd replace the oil pan too. Jsut don't buy anything cheap, I learned the hard way.
It turned out that the leak was coming from the new timing cover between the u-shaped lip that the front of the seal fits in and the timing cover itself. I reused the original pan and timing cover (as crummy as they looked) with a 3rd 1-piece seal and the leak stopped.
If your original timing cover is leaking, try a matched set from GM, or a reputible aftermarket company like Miloden, Edelbrock, or Moroso.
My guess is a high quality timing cover will fix it, but with the trouble you're having, I'd replace the oil pan too. Jsut don't buy anything cheap, I learned the hard way.
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
I have fixed leaks with this method from intake manifolds to oil pans
Use an Xacto knife to V out the sealant that is exposed
Spray the area with starting fluid, let it dry.
Then use the HI- Temp RTV to fill in the area you cleaned out... If its not going to be visible then dont be afraid to be liberal with the RTV
Give it at least 12 hours to dry.
At this point you dont have anything to lose by trying this method.
Use an Xacto knife to V out the sealant that is exposed
Spray the area with starting fluid, let it dry.
Then use the HI- Temp RTV to fill in the area you cleaned out... If its not going to be visible then dont be afraid to be liberal with the RTV
Give it at least 12 hours to dry.
At this point you dont have anything to lose by trying this method.
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Joined: Apr 2005
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Thanks for the suggestions, all.
The old timing cover leaked, so I bought a GM one from the dealer and it continues to leak. Unfortunately, the oil pan is unavailable: I have the L-46 motor that uses the 5-quart pan. No one stocks a stock-type 5 quarter, to my knowledge. The dealer says they're no longer available, and all the vette catalogs sell the 4 quart. The one I have looks good (no dents or visible warpage). My plan is to remove the pan, caulk the heck out of it, especially the seal channel on the timing cover, and let it dry for 2 days and then try again. It's just weird, I drove this car over 1k miles before this started, and now it's like a bullet wound! Glad I'm older now and have more patience....
The old timing cover leaked, so I bought a GM one from the dealer and it continues to leak. Unfortunately, the oil pan is unavailable: I have the L-46 motor that uses the 5-quart pan. No one stocks a stock-type 5 quarter, to my knowledge. The dealer says they're no longer available, and all the vette catalogs sell the 4 quart. The one I have looks good (no dents or visible warpage). My plan is to remove the pan, caulk the heck out of it, especially the seal channel on the timing cover, and let it dry for 2 days and then try again. It's just weird, I drove this car over 1k miles before this started, and now it's like a bullet wound! Glad I'm older now and have more patience....
