I'm freezing "my boys" off and can't get the motor to run over 125 degrees (at least according to my temperature gauge). I'm not getting a great deal of heat thru the heater, so I'm replacing the 160 degree thermostat (which had two small holes drilled thru it for back in the day when all I did was overheat!) for a 180 degree thermostat (that I will NOT drill holes thru, since my overheating problem has been cured eon's ago). I've installed/reinstalled the new thermostat twice now, and both times it leaks. Man, I hate that lower bolt; you get about 1/8 turn each time... takes forever (nice design Ford, thanks!!!).

Question: what, besides the thermostat and gasket, do I need to install the new thermostat so it doesn't leak? When I took the old one off it had some kind of "goo" or sealant type stuff around it. What is it? What's best to use?

Maybe my procedure is wrong:
1. take off old water neck, looking to see how the old thermostat sat in there so I put the new one in the same way (confirmed by directions on new thermostat's packaging);

2. clean intake hole and surface of water neck;

3. put new thermostat in the "inside ring" where it seats/positions itself in the water neck;

4. put "sealant" stuff on gasket, and place gasket onto water neck (kind of holding the thermostat in place), let sealant dry so the whole thing doesn't go cadiwompus when I go to cram it back onto the intake manifold;

5. put sealant on the "intake" side of the gasket (which is now helping to hold the thermostat in place in the center "ring" on the water neck;

6. replace and tighten the two bolts, a little each at a time (like lug nuts on wheels), and tighten as hard as I can.

7. refill radiator and watch the fluid drip out again!!! Dowt!!!!

So what am I doing wrong? This is bonehead stuff, even for an apprentice like me!

Daryl

 

First of all, tightening it as tight as you can is not a great idea. Housings that are overtorqued can easily crack or warp causing a leak. When you take it back apart, carefully inspect the housing for cracks and flatness. If it is suspect in the least, get a new one. Most better parts houses carry them and they're not that expensive. When you go to put it back together, go easy on the gasket sealer. That stuff is the debbil!! I very rarely use it. The gasket is designed to seal the parts and typically doesn't need any help. Clean all the mating surfaces well and run a fine file across the housing surface and the manifold surface to knock down any high spots and make sure that they are true. SPARINGLY use a little RTV sealer in the thermostat groove in the housing and then set the 'stat in place. Let it cure for about 10-15 minutes so that it holds the stat where it needs to be in the housing and then assemble to the manifold with the gasket dry. Tighten the bolts evenly and firmly, but don't jump up and down on the wrench. The torque spec is only somewhere around 20 ft/lbs. It takes a skilled "calibrated elbow" to know about where to stop. Incidently, that bottom bolt on the housing is a lot easier to get to on a manly 351W.

 

Rage,
Thanks for the 4-1-1. I thought maybe it shouldn't be tightened down so hard. And, after inspecting the neck's inside and face where it mates to the intake manifold, I wondered if I should err on the side of caution and just replace the dern-thing? Think I will. I'll get another gasket, some RTV sealer, and gasket sealer (if it's different from the RTV sealer~ I'll ask my local parts store guy), and give her another go! I've got a torque wrench that I can get to the top bolt on. Based on the "feel" of that, I'll do my best to tighten the lower bolt the same.

BTW, I WISH I had a 351... so much so that I'm beginning to contemplate stroking my 302 to a 347. Grrr......
...And then the money issue rears its UGLY head....

Thanks again,
Daryl

 

Daryl

Couple more tips if you get desperate. Don't even think about a chrome t-stat housing that doesn't have an o-ring inset. A new stock housing is better if yours is damaged. Sealing chrome to aluminum intakes can be tough. Are you still running a Edelbrock Performer?

Is your 302 a little soft on the transition to OD? Have you given any thought to changing your rear end gears?

 

'Fenders,
I got a chrome replacement with an O-ring, put it on, checked for leaks (none).... THEN realized it didn't have the spigot on top for the heater hose. Dowt!!! After 3x taking the original water neck on/off, I was a little anxious to get the friggin' thermostat over and done with (as you can imagine). So, back to the original water neck. I filed it flat and cleaned it and the intake. Installed the thermostat, using the proper gasket sealers here and there. I even got the BOTTOM bolt back on with not too much hassle (guess I'm getting good at it by now ) . Then what happened, you ask? Yep, while using the torque wrench to DELICATELY apply the proper amount of pressure to the top bolt, the head tore off it. Aaaaaahhhhh..... @#$%! (parental discression advised; edited for adult, explict content; must be over 18 to read).
So........ I'm going to ask around to see if I can find someone to come up to the house and tap that little sucker outta there. Razzle-frazzle-gull-dernit..... Aaaarrrggghhhh !!!

Regarding the AOD/changing rear gears: I put the 3.50 gears back in before the AOD got installed; way ahead of you on that one (for once). Funny you should mention though... the throttle does "bog" a bit. Seems to be in no-man's land between kicking down and gettin good gas and givin her just enough gas to maintain current speed.

Daryl

 

Daryl

Just kidding on the gear swap, I know you have done more than one ring and pinion change already. You are likely to have a little flat spot on the 3-OD shift with anything but an engine that makes lots of torque on the very low end. From your previous posts, sounds like the AOD swap was acceptable overall. Did you see a significant increase in MPG?

 

Haven't been through a tank of gas yet, so can't give you any mpg numbers as yet. I'll let you know after I refill and break out the calculator! FYI: old mpg before AOD= 10mpg.

Daryl