R & R Thermostat w/203 and now I cant get it to seal. Put the o-ring in place, put the bolts in holes, started bolts and then slowly dropped the housing, with a bead of orange Permatex, onto the o-ring and tightened. Still leaks Did I just get out of bed on the wrong side this week?
BTW/all the surfaces were clean and smooth.

 

i had similar issues when trying to reuse my old one. it looked perfect, but just would not seal. 20 bucks put an end to that headache- bought a new neck.

 

The flange could be streched from being over torqued.
Check it on a sheet of glass. Sometimes you can peen it back.
Or just get a new neck.

Bill

 

When I did my 203 I purchased a new neck and it leaked.

Went back to the old neck but this time followed directions .. make sure the surfaces are completely dry. Then used a bit of RTV (gray) I think .. on the seal itself and put it on pump housing. Let it set up for 30 min or so then like you started bolts together and slowly tightened all three so no one bolt could deform the housing.

Worked for me .. no more leaks

 

And I thought I was the only one...I posted just a couple nights ago when I installed my 203 and had the same troubles.

I fixed mine last night with (another) new neck. I don't think that was the problem though as it looks like the o-ring had slipped out of place. I found that when using RTV the o-ring likes to stick to the water neck and it's very easy to get it out of place.

 

Thanks to all of you. Will try it tomorrow in the daylight as its sitting on the drive. We had 57 degrees today so I stripped and of course the neighbors complained, about the stink I mean.

 

I replaced the neck last time because it wouldn't seal.

It held for about 4 months, and now it weeps when cold. I didn't use RTV, and I'll be rectifying that soon.

 

7.3 diesel silicone from ford fixes everything.........

 

mine leaked with a new housing also even with permantex...my solution..add gobs of permatex and it went ahaid and sealed

 

I have never used RTV. Gasket only and never had any leaks.
Cannot even count how many i have changed.

Question for the leakers.
Any rust or eroding/pitting inside the neck or on the mating
flange. Or the pump?

Bill

 

New neck, leaked. Used 'The Right Stuff'' under and over O ring, didn't wait-just tighten, no leaks.

 

New pump, new neck, new 203 stat, new seal = leaked
New pump, old neck, 203 stat, another new seal + rtv = no leak

Not a lot of rtv though, just as if you were lubing an o-ring. That's my story and I'm sticking to it. In reality though I probably just purchased a neck with bad flange although it look OK to me. Did not try the glass test. I still have the new neck so I'll check that out.

 

IH produced a few mil of 7.3 units.
Not one left the factory with RTV. Hmmmm.
The 7.3 in the as built T444E does not have this leak problem. Hmmmm.

Bad installs? Cheap replacement parts? Ford application thing?
Granted the oem neck is a stamped part and press fit with 3 tack welds.
With just the gasket sometimes its tuff to remove the neck after a year.

I hate RTV. You installed it to seal the t-stat but down the road you find
it in the oil cooler.
Bill

 

OK It's snowing so I'm going out and do it anyway. If you hear loud unidentifiable sounds comeing from your stereo it's just me. Thanks to All

 

K maybe you should shower first this time....