[Pepi]

So I have been battling a leak at my thermostat for quite a long time. Last year I took the housing to a piece of sandpaper that was stuck to a piece of glass, so that is perfectly smooth. I then tried taking the housing to to the intake with sandpaper stuck to it and tried to make sure the intake was true. Hard to do with such little space. Well it was still leaking after I did all of this, even though it took a while to show up.

I pulled the housing today and the housing still looks really good, but the intake doesn't look all that great. My thought was to pull the intake and take intake and housing to a machine shop and see of they could true them both up and then make sure to cut in the groove for the thermostat to sit in to make sure it doesn't sit up too high.

Any thoughts on this? Is there a decent way to true it up on the car without removing intake?

Here is some pictures of the intake and a picture of the still clean housing.

Thanks,
Karl

[b-man]

You should be able to get the thermostat gasket sealing surface on the intake flat enough by using a large flat file that's nice and sharp.

As long as it hasn't sat on the bottom of a lake for an extended period of time it should clean up fairly quickly.

Cutting that surface on a mill and boring that groove for the thermostat to seat down at a machine shop will cost you more than simply finding another intake that's in better shape.

Dress it down with a flat file and get it done.

[dataway]

Don't over tighten the housing either .... find out what the torque spec is and use that. Sometimes on odd shaped parts, over tightening can actually cause them to warp in a way that will make them leak worse ... specially aluminum parts.

If that is all pitting that I see on the intake side ..specially on the front bolt ... you are going to have to clean that up a lot to make it seal.

Yep ... go out and purchase a new, quality, flat file, smoke some pot and spend a couple of hours listening to your favorite music and patiently file that intake flat and smooth again

[steve25]

Remove it again , clean up both sides and then wipe both sides down with Actone, enough to to get into any corrosion pores in the manifold side or the T stat side.

It all must be 100 % free of antifreeze !

Next get some blue silicone gasket maker and apply a bead to the intake side and let it set up for 20 minutes.
After 20 minutes bolt on the water outlet and let it cure over night.

You need to apply a big enough bead of sealer to have come out the sides a good amount , then the next day you can trim it back with a single edge blade and your golden!

[FrankieT/A]

The file trick works great. The pot smoking is optional, but I would use Ultra Grey Permatex...

[Pepi]

Thanks guys, I will try what you all suggested. There is just so little room to do this in the car, but I'll try removing the alternator to get more room and make sure I am going flat and true. This is the original intake, and would like to keep it especially with the date code being correct.

Steve, when the engine was rebuilt back in 96 and the engine re-builder I think did that, because he used a black RTV or similar. It oozed to the inside also, and a few years ago when I pulled my radiator, you could see it coming through some of the rows. That just has me leary of using anything like that again. Battling how this thing likes to run a little hot and I often wonder if he used that stuff anywhere else and if it could be blocking any passages in the block.

Thanks,
Karl

[grivera]

This stuff works great for applications like yours:

Permatex 22071 Water Pump and Thermostat RTV Silicone

https://www.google.com/url?sa=t&rct=...UXZq_FJtv7ms-A

[tjdjr]

coat both surfaces with dykem or color with marker and do the file trick, when both surface have no coloring on them they should be flat enough for a good seal..

[Pepi]

So I started on the intake with a file, a couple of passes took the real light stuff off. I think it was more staining, but there has always been some deep corrosion going on towards the passenger side.

I pulled the EGR ported Vacuum switch, fuel line and alternator just to give me more room. I am going to color it with a marker and get a small piece of glass to put self adhesive sand paper on so that way I go across the whole surface at the same time. Otherwise I am worried with a file that I might push down too much as I cross in certain spots and will end up getting rid of the corrosion, but will create a low spot.

[BLANK1]

Get a Teflon gasket from Tin Indian Performance. No need for sealers and they don't leak and are reuseable.

[lust4speed]

The specific Permatex gasket sealer would be your first choice, but the Ultra Gray will be too a close second to call. Reason we recommend Ultra Gray is that it really likes to stick to itself, and I've never seen it come off inside an engine and migrate. Same goes for Ultra Black and The Right Stuff, but the list ends there. I've fished clear, red, and blue out of all sorts of places inside engines we've taken down.

Always a good idea to wait 24 hours to let any silicone set up. I've seen guys get away with slapping engines together and firing them up, but the waiting period really insures the silicone is fully bonded to the parts and to itself.

I do like the Teflon gaskets, but the Ultra Gray will do the job even if surfaces are heavily pitted and tore up.

[luvagoat]

Also make sure your bolts aren't just a hair too long

[rickschabener]

I used Permatex's The Right Stuff on my son's S10 thermostat housing that had a bad nick in one surface, and it has worked great. Use it instead of any other gasket, and I would always let it dry overnight before I added any fluid. Also, make sure you use it inside and outside the bolt holes.

And, as mentioned above, screw both bolts in all the way without the housing in place and measure how much thread is exposed. Measure that against the housing thickness to make sure your bolts aren't bottoming out.

[Goatracer1]

Have you pressure tested the system? All too often I have seen the gasket blamed for a leak when it is actually the hose that is leaking. The fluid is seeping between the hose and the housing. The cheap screw clamps don't help the situation. You need the spring loaded type of clamp. Just a suggestion.

[hurryinhoosier62]

Cast iron or aluminum thermostat housing? I've never had anything but trouble with the aluminum housings.

[tom s]

this stuff is really good.
http://www.valco-cp.com/Hylomar.htm

[Pepi]

Originally Posted by Goatracer1

Have you pressure tested the system? All too often I have seen the gasket blamed for a leak when it is actually the hose that is leaking. The fluid is seeping between the hose and the housing. The cheap screw clamps don't help the situation. You need the spring loaded type of clamp. Just a suggestion.

Yes, I have done that. I can actually see it seeping from the gasket area. That area that it does seep from has a lot of pitting/corrosion. I have also checked the bolt lengths and those are good.

As an update: I sanded it down after taking the alternator off and fuel line to the carb and removed my ported vacuum switches, so I would have more room to get to it. I used a large DA sander to be able to cover the whole area at once. It took quite a bit to get it all gone. So much that now the thermostat doesn't sit in the lip anymore on one side. I tried putting the thermostat housing back on without gasket or thermostat and I could fit a .013 feeler gauge under the middle of it on both the front and back. If you considered the sides where the bolts go.I put the housing on a piece of glass and tried checking that I had a hard time even getting a .0015 under it. So the housing is good and true.

I could send mine to a place in Michigan that can build the intake up and then machine it down and cut the lip into it so you wouldn't even be able to tell it was done. But HFR had an intake that had a date the next day from mine, so we worked out a deal. I'll post pictures tomorrow of my finished intake.

[Pepi]

Originally Posted by hurryinhoosier62

Cast iron or aluminum thermostat housing? I've never had anything but trouble with the aluminum housings.

It is the original Aluminum housing. But that is actually good and true. I sanded that down last year on a sheet of glass with DA paper stuck to the glass.

[Pepi]

Originally Posted by tom s

this stuff is really good.
http://www.valco-cp.com/Hylomar.htm

I have tried that also, and have always had good luck, this one just didn't want to seal up.

[Squidward]

Originally Posted by lust4speed

Always a good idea to wait 24 hours to let any silicone set up. I've seen guys get away with slapping engines together and firing them up, but the waiting period really insures the silicone is fully bonded to the parts and to itself.

This. I like to do a light assembly after coating both sides of gasket with Ultra black/grey. I put on the water neck, start threading the bolts, and give the neck a little wiggle with the slop of the bolt holes to help rtv distribution. Then I delicately finger tight the bolts to keep even contact. I wait until the next day and then do final torque.

I have used JB Weld on a water crossover surface with severe pitting, and then used a file to true it up. But for the most part, rtv should be able to take care of business.