I have a chrome O-ring water neck that has been replaced twice. I have cleaned the manifold untill there is no gasket sealer, made sure manifold was level, scuffed the new water neck underneath in hopes to get a better seal, placed a nice thin bead of gasket sealer ....still I have a leak in the rear part of the water neck. Any suggestions on how to keep this from leaking? Thank you
The o-ring thermostat housings are a great idea, but they are usually badly cast or machined parts. I finally got sick of the leak on mine and replaced it with a good-ol GM gasketed housing.How often are you really gonna need to remove the t-stat anyway??
68RS/Z28 Klone, Long rod 357 , T-56, 3.89 9"
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Have you checked to see that the surface of the waterneck is true? And, have you checked to see that the mounting surface on the manifold is true? If either one is off, the water pressure will find the weak spot and cause the leak. I have used o-ring seal water necks on my 69 and 75 and have never had a leak.
Make sure that the o-ring doesn't have any cuts in it. Also make sure that the groove that the o-ring sits in is perfectly clean. I had one leak because of a very small cut in the o-ring that I overlooked. Hope this helps.
I always "true up" a stock thermostat housing on a piece of emery paper laid on a piece of glass; several swipes back and forth, and the pattern will tell you immediately if it's flat or not (many aren't). If not, keep working at it until it's flat. I use the blue Fel-Pro molded plastic gasket with the molded-in silicone rib seal - never had a leaker. [img]graemlins/thumbsup.gif[/img]
John - do you have the fel-pro part number? I've been getting the ones I use from a local corvette shop that said they are GM gaskets. Local Kragan and such don't know what I'm asking for and it's always turned out to be late Sat or Sun when I find myself needing one so I haven't had the chance to at at the Chevy parts counter...
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There are several problems to look at with oring sealing surfaces. First with an oring installation it is not critical how true the surface is except to the point of making sure that there is not metal to metal contact before the oring is fully compressed. It's not like a standard water neck installation, the oring is doing the sealing, not the water neck to manifold contact. In fact if you have waterneck to manifold metal to metal contact you are compromising your seal at your oring as it is not being loaded because you are distributing the load in the wrong place, should be metal rubber metal, not metal on metal. Second make sure the oring is the proper size and made of material compatible with antifreeze, orings are designed to be used with very specific fluids and temperature ranges. Third make sure the oring when sitting in the groove is of adequate cross sectional thickness to protrude significantly from it's oring groove, this will guarantee it's contact and proper compression when mating the water neck to the manifold. Also make sure the oring isn't rolled and most importantly that the entire groove the oring sits in is clean, true and free of even a MINOR scratch. One small insignificant looking scratch in the groove and it will leak. Never reuse an oring, they are designed to take a set and will cold flow to fill the groove when under compression.
Finally many automotive orings lack the quality controls of their aerospace counterparts. I've found many automotive orings with flashing at the seams where they were molded, I've never seen this on any aerospace orings that I work with daily.
Personally I'd toss the chrome water neck, but it should be able to seal if you make sure all the above are checked.
Try using the new FelPro "Blue" gaskets. they are a little more expensive but you can reuse them they cost about $7 bucks at auto zone but you can tighten them as much as you want. They are made of a polyurethane plastic and have the seal already in them. I have had no probs. with crome necks and them sealing after i used the felpro blue gaskets [img]smile.gif[/img]