valve covers leaking - The 1947 - Present Chevrolet & GMC Truck Message Board Network

74 C-30 · 09-10-2009, 06:12 PM

hey guys so today I started my truck for the first time since i replaced the leaky valve cover gaskets, and it started leaking again. I'm going to pull the valve cover off again and re-clean all the surfaces and probably try a bit a gasket-in-a-tube. theyre the stock stamped valve covers. my question is does anybody have any helpful hints on how to keep the covers from leaking? thanks!

79gmcc15 · 09-10-2009, 06:23 PM

well for me Ive only used rubber gaskets and used the gasket sealer on the gasket and valve cover mating surface. I don't have a torque wrench, so I have always taken the bolts hand tight and then go one to two full turns on the bolts with wrench. and mainly make sure the out side bolts are tighter then the others because that seems to leak more then the other side. I am sure what I do is not by the book right, but it does work for me.

85Bowtie · 09-10-2009, 06:27 PM

You need to bolt them on, run the engine, then tighten them again. The gaskets get softer when the engine is hot, so you have to go back and take the slack out thats there. Just use a 1/4 drive ratchet and hold it by the head and just give it a firm turn until it tightens al the way, and tighten from the middle bolt outward criss-crossing. Then repeat the pattern until they're tight

I had to do this a couple of times on the 318 in my cop car.

79gmcc15 · 09-10-2009, 06:42 PM

what middle bolt? isnt there only 4 bolts on a SBC? they are at the corners, right? I know the vortec motors had the ones on top...

3r!c84 · 09-10-2009, 07:51 PM

just do a x

3r!c84 · 09-10-2009, 08:09 PM

do u have this?

85Bowtie · 09-10-2009, 09:21 PM

Quote:

Originally Posted by 79gmcc15

what middle bolt? isnt there only 4 bolts on a SBC? they are at the corners, right? I know the vortec motors had the ones on top...

Yeah thats right, haven't looked at one in awhile, maybe thats why they leak.....

Chrysler uses 5 bolts, bottom middle, 2 diagonal across at the top, then 2 at bottom corners, and they don leak.

Just cross them then, but you have to retighten them a few times to seat right.

1984 swb chevy · 09-10-2009, 09:46 PM

you should take your valve cover off and look at the bolt holes. If the valve covers were over tightened the sealing surface of the valve cover may not be flat. Check the area around the hole. If it isnt flat tap it down with a small hammer to get the surface area flat. When you put it back together do not over tighten them.

70k52wd · 09-10-2009, 10:02 PM

Quote:

Originally Posted by 1984 swb chevy

you should take your valve cover off and look at the bolt holes. If the valve covers were over tightened the sealing surface of the valve cover may not be flat. Check the area around the hole. If it isnt flat tap it down with a small hammer to get the surface area flat. When you put it back together do not over tighten them.

What he said is most likely the problem. Hold the edge of the cover upside down on a flat edge and carefully tap until the surface is flat. Or, I use a piece of 2x4 wood the length of the cover flange, then one good whack will get it nice and flat.

74 C-30 · 09-10-2009, 09:08 PM

yes i have the little load spreaders. after i ran it once i tightened down all the bolts again, and ran it again and she still leaked, but it took awhile to start leaking, i'll recheck the bolts and tighten them like 79gmcc15 said, then if all else fail, i'll take the valve cover off. btw its a cork gasket

silvereagle07 · 09-10-2009, 09:47 PM

I agree with 1984 swb chevy. Check the bolt holes. I scuff the valve cover, where the gasket sits, with a Scotchbrite pad and apllied "gorilla snot" (trim adhesive) between the gasket and the cover. It will help hold the gasket in place. That method always worked on stock or chrome valve covers for me.

74 C-30 · 09-10-2009, 09:53 PM

as posted above, stock stamped with cork gaskets

ghettoluxury · 09-11-2009, 12:03 AM

Quote:

Originally Posted by 74 C-30

as posted above, stock stamped with cork gaskets

Put rubber in! cork will always leak

74 C-30 · 09-10-2009, 10:06 PM

ok guys thanks for all the ideas! hopefully once this is solved, for the first time in 12 years I'll get the ol' truck inspected and on the road!

Rons86 · 09-11-2009, 01:48 PM

All the things mentions above are great and I agree with them all. Another thing to keep in mind is that the crankcase builds pressure and needs ventilation. Do you have and vents on the valve covers? I say this because of a similar experience with non vented valve covers that I could not get stopped leaking. We fnially bought some with vents and the leaking stopped immediately bacause of crankcase pressure.

09-10-2009, 06:12 PM	#1
74 C-30 Dually Pride Join Date: Jun 2008 Location: NH Posts: 540	valve covers leaking hey guys so today I started my truck for the first time since i replaced the leaky valve cover gaskets, and it started leaking again. I'm going to pull the valve cover off again and re-clean all the surfaces and probably try a bit a gasket-in-a-tube. theyre the stock stamped valve covers. my question is does anybody have any helpful hints on how to keep the covers from leaking? thanks! __________________ If I have to explain, you wouldn't understand. '74 Chevy C-30 350/4 speed/dually '94 Ford Ranger

09-10-2009, 06:23 PM	#2
79gmcc15 Gettin It One Pice At A Time Join Date: Oct 2004 Location: everett, washington Posts: 2,688	Re: valve covers leaking well for me Ive only used rubber gaskets and used the gasket sealer on the gasket and valve cover mating surface. I don't have a torque wrench, so I have always taken the bolts hand tight and then go one to two full turns on the bolts with wrench. and mainly make sure the out side bolts are tighter then the others because that seems to leak more then the other side. I am sure what I do is not by the book right, but it does work for me. __________________ RIP ELJAY Work In Progress 1979 GMC C1500 Trailering Special. Getting the truck done, one piece at a time. “You can tell a lot about a fellow’s character by his way of eating jellybeans.”Ronald Reagan “I don’t know the key to success but I know the key to failure is trying to please everybody.” Bill Cosby

09-10-2009, 06:27 PM	#3
85Bowtie Registered User Join Date: Mar 2009 Location: TN Posts: 410	Re: valve covers leaking You need to bolt them on, run the engine, then tighten them again. The gaskets get softer when the engine is hot, so you have to go back and take the slack out thats there. Just use a 1/4 drive ratchet and hold it by the head and just give it a firm turn until it tightens al the way, and tighten from the middle bolt outward criss-crossing. Then repeat the pattern until they're tight I had to do this a couple of times on the 318 in my cop car. __________________ '69 Dodge Charger R/T 440, 727, 3.55 Sure Grip '68 Plymouth Road Runner 383, 727, 3.23 Sure Grip '89 Dodge Diplomat ex cop car 408, 727, 3.55 Sure Grip '77 Dodge Monaco ex cop car 440, 727, 2.71 '79 Dodge 'Lil Red Express pickup 360, 727, 3.55 Sure Grip '12 Dodge Challenger SRT8 392, M6, 3.92 '85 Chevrolet C-10 SWB 2wd 305, TH350, 2.73 Last edited by 85Bowtie; 09-10-2009 at 06:28 PM.

09-10-2009, 06:42 PM	#4
79gmcc15 Gettin It One Pice At A Time Join Date: Oct 2004 Location: everett, washington Posts: 2,688	Re: valve covers leaking what middle bolt? isnt there only 4 bolts on a SBC? they are at the corners, right? I know the vortec motors had the ones on top... __________________ RIP ELJAY Work In Progress 1979 GMC C1500 Trailering Special. Getting the truck done, one piece at a time. “You can tell a lot about a fellow’s character by his way of eating jellybeans.”Ronald Reagan “I don’t know the key to success but I know the key to failure is trying to please everybody.” Bill Cosby

09-10-2009, 07:51 PM	#5
3r!c84 Badass Join Date: Jan 2009 Location: lox. fl Posts: 4,586	Re: valve covers leaking just do a x __________________ Think outside the box? -84c10 (1stcar)→My Build← -00 Saturn 5spd drop a gear and disappear! 1/4:13:90

09-10-2009, 08:09 PM	#6
3r!c84 Badass Join Date: Jan 2009 Location: lox. fl Posts: 4,586	Re: valve covers leaking do u have this? Attached Images __________________ Think outside the box? -84c10 (1stcar)→My Build← -00 Saturn 5spd drop a gear and disappear! 1/4:13:90

09-10-2009, 09:46 PM	#8
1984 swb chevy Registered User Join Date: Nov 2007 Location: New Jersey Posts: 466	Re: valve covers leaking you should take your valve cover off and look at the bolt holes. If the valve covers were over tightened the sealing surface of the valve cover may not be flat. Check the area around the hole. If it isnt flat tap it down with a small hammer to get the surface area flat. When you put it back together do not over tighten them. __________________ 2010 Tahoe 1984 C10 2005 Harley FLH 1941 Willys Pickup (will never get it done) not for sale

09-10-2009, 09:08 PM	#10
74 C-30 Dually Pride Join Date: Jun 2008 Location: NH Posts: 540	Re: valve covers leaking yes i have the little load spreaders. after i ran it once i tightened down all the bolts again, and ran it again and she still leaked, but it took awhile to start leaking, i'll recheck the bolts and tighten them like 79gmcc15 said, then if all else fail, i'll take the valve cover off. btw its a cork gasket __________________ If I have to explain, you wouldn't understand. '74 Chevy C-30 350/4 speed/dually '94 Ford Ranger

09-10-2009, 09:47 PM	#11
silvereagle07 Registered User Join Date: Sep 2008 Location: Bailey, NC Posts: 2,462	Re: valve covers leaking I agree with 1984 swb chevy. Check the bolt holes. I scuff the valve cover, where the gasket sits, with a Scotchbrite pad and apllied "gorilla snot" (trim adhesive) between the gasket and the cover. It will help hold the gasket in place. That method always worked on stock or chrome valve covers for me. __________________ Jeramy '84 GMC project truck '85 Chevy 4X4 SOLD '07 Chevy Trailblazer SS 5th Annual SHPHC Car/Truck Show Pics http://67-72chevytrucks.com/vboard/s...d.php?t=543605 UPDATED PICS! CHECK 'EM OUT Last edited by silvereagle07; 09-10-2009 at 09:52 PM.

09-10-2009, 09:53 PM	#12
74 C-30 Dually Pride Join Date: Jun 2008 Location: NH Posts: 540	Re: valve covers leaking as posted above, stock stamped with cork gaskets __________________ If I have to explain, you wouldn't understand. '74 Chevy C-30 350/4 speed/dually '94 Ford Ranger

09-10-2009, 10:06 PM	#14
74 C-30 Dually Pride Join Date: Jun 2008 Location: NH Posts: 540	Re: valve covers leaking ok guys thanks for all the ideas! hopefully once this is solved, for the first time in 12 years I'll get the ol' truck inspected and on the road! __________________ If I have to explain, you wouldn't understand. '74 Chevy C-30 350/4 speed/dually '94 Ford Ranger

09-11-2009, 01:48 PM	#15
Rons86 Registered User Join Date: Sep 2008 Location: Holt, Missouri Posts: 94	Re: valve covers leaking All the things mentions above are great and I agree with them all. Another thing to keep in mind is that the crankcase builds pressure and needs ventilation. Do you have and vents on the valve covers? I say this because of a similar experience with non vented valve covers that I could not get stopped leaking. We fnially bought some with vents and the leaking stopped immediately bacause of crankcase pressure.



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