Timing cover oil leak question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

skillet · 09-15-2005, 01:12 PM

My timing cover is leaking oil at the bottom. Is there supposed to be oil behind the timing cover and what would be the sources, or most common source for a leak? Like, is there a crank seal that fails or what? Or is the oil just woriking it's way from the oil pan? I noticed before the problem began, a high pitched noise from the front of the truck had developed. You could hear the noise around 60 mph and above, but it would stop if I dropped down below 60. I'm trying to figure out how much to take apart to diagnose and fix it and also to decide if it can be done in an apartment parking lot. Thanks very much for any comments.

dubie · 09-15-2005, 01:48 PM

I had the same problem on my 350 . i replaced the oil pan gasket with a 1 piece and never had to worry about it again

sneakysnake · 09-15-2005, 02:09 PM

Clean around it real good, and then look closely for the leak,if its leaking around the crank shaft, pull the harmonic balancer and replace seal.if its leaking lower then you will have to pull the oil pan to replace the gasket.

Fred T · 09-15-2005, 05:39 PM

Also, if it's the oil seal leaking, there is usually a groove in the shaft of the balancer. This is easily fixed with a redi-sleeve, slides over the shaft.

I'm concerned about the noise, though. Does it occur when the engine is at speed?

skillet · 09-15-2005, 07:02 PM

There is no noise when the engine is idling or at low speeds, just when I get on the highway and start getting above 55 mph. I will replace the oil pan gasket with a 1 piece and also install a new timing cover gasket and go from there.

tomatocity · 09-15-2005, 07:30 PM

Quote:

Originally Posted by Fred T

I'm concerned about the noise, though. Does it occur when the engine is at speed?

Sounds like a body part or antenna that is causing the noise.

fastwillie 696969 · 09-15-2005, 08:02 PM

this would be a good time to replace the timming cover with a two pc timming cover

skillet · 09-29-2005, 08:53 PM

Problem fixed! I replaced my oil pan gasket with the 1 piece blue gasket from Fel-Pro and so far so good, no oil leak! Gasket # 0S 34509T, fits '57-'74. Thanks very much for all the help!

*bisquik65* · 09-29-2005, 09:49 PM

I have had the front seal leak bad after 30 miles on fresh machine shop rebuild,changed the front crank seal,same thing...when them align bore a block...it moves the crankshaft up into the block deeper...Is there i fix for this? Anyone ever have this problem?

Fred T · 09-29-2005, 10:51 PM

Bisquik - Are you using an old balancer? If so, did you put a redi-sleeve on it? Any grooves in the balancer will cause leaks.

If it's a new balancer, then you need to center the timing cover on the crankshaft. What I can't recall is if there are alignment pins for the cover. If there are, they need to be taken out of action, easiest way is to open up the holes so the cover can move up.

Pull the balancer and cover and clean things up. Put a new seal in and glue the gasket to the cover and let it dry. I prefer a non-hardening sealer, such as the aviation sealer. Apply a thin coat to the back side of the gasket and the block. Put the cover on with two bolts that are loose. Then put the balancer on far enough to engage the seal, allowing the cover to move in alignment. Snug down the bolts and put in the rest of the bolts. You might have to pull the balancer off to install the bolts, depends on the application. Should solve your problem.

70c10 · 09-30-2005, 07:26 AM

skillet- I just saw on advance auto parts site the part number changes in 1975. What's the difference in pans?

skillet · 09-30-2005, 09:16 AM

I'm not sure the difference in pans, but the number does change.

0S 34509T -- Chevrolet small-block V-8 '57-'74

OS 34510T -- Chevrolet small-block V-8 '75-85

Os 30061T -- Chevrolet big-block V-8 '65-90

*bisquik65* · 09-30-2005, 03:01 PM

I never wold have thought of doing that,Thanks.....Erick

Quote:

Originally Posted by Fred T

Bisquik - Are you using an old balancer? If so, did you put a redi-sleeve on it? Any grooves in the balancer will cause leaks.

If it's a new balancer, then you need to center the timing cover on the crankshaft. What I can't recall is if there are alignment pins for the cover. If there are, they need to be taken out of action, easiest way is to open up the holes so the cover can move up.

Pull the balancer and cover and clean things up. Put a new seal in and glue the gasket to the cover and let it dry. I prefer a non-hardening sealer, such as the aviation sealer. Apply a thin coat to the back side of the gasket and the block. Put the cover on with two bolts that are loose. Then put the balancer on far enough to engage the seal, allowing the cover to move in alignment. Snug down the bolts and put in the rest of the bolts. You might have to pull the balancer off to install the bolts, depends on the application. Should solve your problem.

skillet · 09-30-2005, 07:06 PM

Egad! My leak reared it's ugly head again today. So now I am repalcing the timing cover gasket and seal. The Fel-Pro gasket set I bought includes everything you need, timing cover gasket, harmonic balancer seal and a repair sleeve.

09-15-2005, 01:12 PM	#1
skillet Registered User Join Date: Sep 2000 Location: denton, tx, usa Posts: 176	Timing cover oil leak question My timing cover is leaking oil at the bottom. Is there supposed to be oil behind the timing cover and what would be the sources, or most common source for a leak? Like, is there a crank seal that fails or what? Or is the oil just woriking it's way from the oil pan? I noticed before the problem began, a high pitched noise from the front of the truck had developed. You could hear the noise around 60 mph and above, but it would stop if I dropped down below 60. I'm trying to figure out how much to take apart to diagnose and fix it and also to decide if it can be done in an apartment parking lot. Thanks very much for any comments. __________________ 69 SB GMC LWB Fleetside 350, 09 Pontiac Vibe 2.4 liter

09-15-2005, 01:48 PM	#2
dubie Registered User Join Date: May 2000 Location: Flin Flon, Manitoba, Canada Posts: 8,855	I had the same problem on my 350 . i replaced the oil pan gasket with a 1 piece and never had to worry about it again __________________ My name's Tim and I'm a truckaholic My 56 Chevy shop truck build http://67-72chevytrucks.com/vboard/s...d.php?t=562795

09-15-2005, 02:09 PM	#3
sneakysnake It's a catastrophic success. Join Date: Jan 2003 Location: Oklahoma Posts: 2,077	Clean around it real good, and then look closely for the leak,if its leaking around the crank shaft, pull the harmonic balancer and replace seal.if its leaking lower then you will have to pull the oil pan to replace the gasket. Attached Images

09-15-2005, 05:39 PM	#4
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	Also, if it's the oil seal leaking, there is usually a groove in the shaft of the balancer. This is easily fixed with a redi-sleeve, slides over the shaft. I'm concerned about the noise, though. Does it occur when the engine is at speed? __________________ Fred There is no such thing as too much cam...just not enough engine.

09-15-2005, 07:02 PM	#5
skillet Registered User Join Date: Sep 2000 Location: denton, tx, usa Posts: 176	There is no noise when the engine is idling or at low speeds, just when I get on the highway and start getting above 55 mph. I will replace the oil pan gasket with a 1 piece and also install a new timing cover gasket and go from there. __________________ 69 SB GMC LWB Fleetside 350, 09 Pontiac Vibe 2.4 liter

09-15-2005, 08:02 PM	#7
fastwillie 696969 ~Rest In Peace~ Join Date: May 2005 Location: CALIFORNIA NOR CAL Posts: 9,707	this would be a good time to replace the timming cover with a two pc timming cover __________________ is it fast ? it has a lighting bolt donut? B___H please, I can remove 90% of your so called "beauty" with a kleenex

09-29-2005, 08:53 PM	#8
skillet Registered User Join Date: Sep 2000 Location: denton, tx, usa Posts: 176	Problem fixed! I replaced my oil pan gasket with the 1 piece blue gasket from Fel-Pro and so far so good, no oil leak! Gasket # 0S 34509T, fits '57-'74. Thanks very much for all the help! __________________ 69 SB GMC LWB Fleetside 350, 09 Pontiac Vibe 2.4 liter

09-29-2005, 09:49 PM	#9
bisquik65 Account Suspended Join Date: Apr 2004 Location: N.C. high country Posts: 6,107	I have had the front seal leak bad after 30 miles on fresh machine shop rebuild,changed the front crank seal,same thing...when them align bore a block...it moves the crankshaft up into the block deeper...Is there i fix for this? Anyone ever have this problem?

09-29-2005, 10:51 PM	#10
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	Bisquik - Are you using an old balancer? If so, did you put a redi-sleeve on it? Any grooves in the balancer will cause leaks. If it's a new balancer, then you need to center the timing cover on the crankshaft. What I can't recall is if there are alignment pins for the cover. If there are, they need to be taken out of action, easiest way is to open up the holes so the cover can move up. Pull the balancer and cover and clean things up. Put a new seal in and glue the gasket to the cover and let it dry. I prefer a non-hardening sealer, such as the aviation sealer. Apply a thin coat to the back side of the gasket and the block. Put the cover on with two bolts that are loose. Then put the balancer on far enough to engage the seal, allowing the cover to move in alignment. Snug down the bolts and put in the rest of the bolts. You might have to pull the balancer off to install the bolts, depends on the application. Should solve your problem. __________________ Fred There is no such thing as too much cam...just not enough engine.

09-30-2005, 07:26 AM	#11
70c10 67-72 Addict! Join Date: Feb 2002 Location: The TAX State! Posts: 7,857	skillet- I just saw on advance auto parts site the part number changes in 1975. What's the difference in pans? __________________ Jim 1970 C/10 Fleetside w/Ghost Flames Lowered 4.5" front and 4" rear (Raked) 355/350 Turbo w/shift kit 10" Redneck Performance Verter w/2500 stall Hooker Super Comps part#2808-1 Performer RPM Air-Gap 12 Bolt w/3:73 gears- Eaton Posi Comp Cams XE262 with 1.6 Crane Energizers, Road Demon 625 and Brodix IK 180 heads Last edited by 70c10; 09-30-2005 at 08:02 AM.

09-30-2005, 09:16 AM	#12
skillet Registered User Join Date: Sep 2000 Location: denton, tx, usa Posts: 176	I'm not sure the difference in pans, but the number does change. 0S 34509T -- Chevrolet small-block V-8 '57-'74 OS 34510T -- Chevrolet small-block V-8 '75-85 Os 30061T -- Chevrolet big-block V-8 '65-90 __________________ 69 SB GMC LWB Fleetside 350, 09 Pontiac Vibe 2.4 liter

09-30-2005, 07:06 PM	#14
skillet Registered User Join Date: Sep 2000 Location: denton, tx, usa Posts: 176	Egad! My leak reared it's ugly head again today. So now I am repalcing the timing cover gasket and seal. The Fel-Pro gasket set I bought includes everything you need, timing cover gasket, harmonic balancer seal and a repair sleeve. __________________ 69 SB GMC LWB Fleetside 350, 09 Pontiac Vibe 2.4 liter



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