wwiiavfan

Had a slight weeping from the chrome water neck some former PO installed. After removal, cleanup of a ton of permatex, thread chasing etc. I’m left with a slightly corroded sealing surface. (Original intake ‘71 base 350). What is the most likely path to a successful seal? I think all scenarios involve a film of ultra black on the intake to fill in those pits, but what would be the best housing to follow that with? Another o-ring setup? Cast iron flat OEM style with a quality gasket like fel-pro?



Thanks
edit: the existing o-ring housing seems ok, no warping or cracks but the o-ring is used up. I might be able to get an o-ring from work.

67:72

JB-Weld to fill the pits and then sanded flat to the surrounding cast iron. After that I suppose the o-ring would seal fine; I have the original outlet so use the flat gaskets with a light smear of Permatex on each side.

lars

Ditch the o-ring. Sand the crap out of the housing on a piece if 150 sandpaper on a flat workbench surface - get rid of all the chrome plating on the gasket surface. Then, install it with a regular thermostat housing gasket sealed with Permatex Ultra gasket sealant.

Lars

C6_Racer_X

A new O-ring should seal that up just fine. No other sealant is needed, and additional sealant can cause leaks by preventing the O-ring from sealing properly.

The O-rings are available in the "dress up" section at most FLAPS. I know O'Reilly has them.

if you'd rather use a regular thermostat gasket, you'll need to fill and smooth that surface.

lars

I've never seen a chrome housing with o-ring that did not leak. You have to get rid of the chrome on the sealing surface and throw the o-ring in the trash - sand it, or get a stock aluminum or iron water outlet. Most of the chrome o-ringed housings are warped due to the owner trying to tighten it tight enough to stop leaking - you may have to sand it quite a bit to make it flat. Your pitted manifold will seal up just fine using a regular gasket with sealant, as long as its clean. No filling needed of either surface. This is a common problem, and I deal with it regularly.
Lars

Fly skids up!

Ditch that hokey chrome garbage for a stock one.
Remember, chrome won't get you home.

wwiiavfan

I went after the manifold surface with a machinist’s file and got it pretty decent and followed up with some 220 on a flat disc to knock down the heavy file marks. So that side’s good to go, I think. I’ll see if I can find a cast iron one at a local auto parts store. Rock Auto has them but shipping is more than the parts!

Bikespace

Here's the super-fancy cast aluminum water neck I use:
https://www.jegs.com/i/Chevrolet-Per...08470/10002/-1

$5-, and a genuine Chevy part, 10108470

And the $17- gasket:
https://www.jegs.com/i/Fel-Pro/375/2202/10002/-1

HeadsU.P.

Its your car, use what YOU want and not what somebody else's take is on it. If you want anodized color, billet, orange or chrome, do as suggested above, sand.

Chrome does not allow any sealant to adhere to its slippery surface. However, its nothing some sanding won't fix.

Mr. Gasket and others makes a orange silicone water neck gasket. I have no part number handy but instead of a couple bucks, its $25.
But here is the thing. It seals and can be used over & over again.

Also, Permatex makes a special sealant called Water-neck & Water-pump RTV. (AutoZone) Its a little pricey for the small tube you get but works well.
Why is it special? Its glycol proof. Not all Permatex is. Have to read the label.

<<<<<<<<<<< Note the chrome water-neck to the left <<<<<. 12 yrs, not a drop.

HeadsU.P.

Forgot a tip on Water-neck bolts:

In some rare cases with aftermarket units, they come with bolts a smidge too long.
You think you are torquing the housing down tight, but in reality, the bolts are bottoming out in their respective holes (one short, one long)
To check this issue, put both bolts in the Intake w/o the housing and snug by hand. Next, slide the water neck into position (no gasket) and see if the bolt head is below the bolt boss.

pedantic

OP did a good job w/ that flat file.
permatex #2 non-hardening in a small tube. it's not rtv or even its cousin. predates rtv by many decades.

scottyp99

I've always had great luck with thermostat housings and water pumps by making sure both mating surfaces are flat and clean. A very little bit of "tooth" on the mating surfaces won't hurt anything, the crucial thing is flat and clean. A thin smear of Permatex High Tack on both mating surfaces. A thin smear of High Tack on both sides of a regular, ordinary paper gasket. Give it 5 minutes or so to set up a little bit, bolt it together, and then forget about it. I use the same procedure on intake manifold gaskets, and it works great. Also, I concur with those who say ditch the o-ring thermostat housing, those things have always given me nothing but trouble.


Scotty

Duane4238

Permatex #2 is awesome! I've used it for well over 50 years and haven't bothered to try the new stuff when the old stuff works.
Duane