Leaking 455 valve cover
March 10th, 2021, 06:40 PM
#1
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Join Date: Jul 2013
Location: Alexandria Virginia
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Leaking 455 valve cover
I replaced both valve cover gaskets as they were leaking and old. I bought a sett off of eBay Fel Pro the cork/rubber type. The driver side one turned out perfect, no leaks, tighten to 7 lbs with a calibrated Match torque wrench. The passenger side one is a real problem as it leaks at the center lower bolt (tightened at 7 lbs & re-torqued all bolts after driving it a few hours) but it still leaked. I replaced the new gasket with another new gasket and the leak is bigger than before. Could it be bad (old) gaskets? Do i need to put black RTV around the gasket were it leaks? I am at a loss, as any one experienced a similar situation in the past? Is it a common leak in this spot? Also i flattened the valve cover flange portions were the original bolts attach.
March 10th, 2021, 06:50 PM
#2
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Location: St. Michael, MN
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Stop using cork gaskets. If you use felpro buy the rubber ones. Then only hardening permetex on valve cover side of gasket other side dry. I've never had a leak. Now if you really don't want any sealer on it buy the rubber with metal reinforcement in them and keep using them. That's the very best gasket for them.
March 10th, 2021, 07:27 PM
#4
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March 10th, 2021, 09:24 PM
#5
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Location: Poteau, Ok
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If the valve covers are not perfectly straight and flat you'll get leaks. I like to use weather stripping cement on the valve cover side of the gasket. Use a thin coat on both the gasket and the valve cover, let it cure for a bit and then stick the 2 parts together. Then the only real sealing surface is the head and the gasket.
March 11th, 2021, 03:46 AM
#6
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Location: central Indiana
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If the sealing surface is dented or bent, the best gasket in the world won’t help. I bet your going to find the metal around the bolt holes is dimpled from over-torquing the hardware.
Use some wood to support the flange, and use a small hammer to straighten things out. I bet that solves your problem.
Use some wood to support the flange, and use a small hammer to straighten things out. I bet that solves your problem.
March 11th, 2021, 09:16 AM
#9
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Location: Alexandria Virginia
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Chris, you it on the nail. The low spot is right were the lower center bolt is. Some bozo (previous to my ownership) welded an exhaust stud onto the head rite below the low spot which explains everything. I have a spare set of rebuilt heads but for now i will JB Weld that area and see how it goes. Thanks to everyone that contribute it.
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