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skilew
03-21-2005, 08:04 AM
Engine acts as though the thermostat is stuck open. Will not get over 120 degrees F so I decided to replace it.

Tried to replace thermostat this weekend, removed the two cover bolts but the cover acts as though it were welded on. It will not budge. I did not want to be too aggressive and crack the cover. Any suggestions?

jsonova99
03-21-2005, 08:12 AM
Could you try heating it up a little with a heat gun or something? That little bit of expansion might be enough to knock it loose. I can't picture what mine looks like right now so I don't know if this is feasible or not. I'm sure somebody else will chime in with some ideas.

PeteS
03-21-2005, 08:18 AM
I had a similiar problem in my '88 with the thermostat, and the cover was seized a bit as well. Here's what I'd do. Squirt some PB Blaster down the bolt holes, and around the seams of the cover. Tap it gently with a hammer, or rubber mallet. Repeat, then pull it off.

Once you access the t-stat, if you notice it OPEN, that explains your temperature problems -- mine was corroded wide open. Let us know how it goes.

Footin
03-21-2005, 08:30 AM
You said you removed the "two" cover bolts, I believe your are removing the wrong cover. Doesn't the t-stat houseing have 3 bolts holding it together? You are probably removing the neck into the manifold and the stat is in the other housing.

dsoby
03-21-2005, 10:12 AM
Lew,
I can't tell what kind of boat you have but my engine (LTR) has a 120 deg. thermostat as standard equipment.

jimmer2880
03-21-2005, 11:17 AM
You said you removed the "two" cover bolts, I believe your are removing the wrong cover. Doesn't the t-stat houseing have 3 bolts holding it together? You are probably removing the neck into the manifold and the stat is in the other housing.

I have to agree - on my '95 PS190, it's 3 bolts holding the cover on the T-stat. What boat do you have?

Lance
03-21-2005, 11:54 AM
My 87 prostar also has three. The cover is the triangular shaped housing at the very top front of these older Ford engines.

skilew
03-21-2005, 12:54 PM
I have a 1993 Ford 351 with the GT-40 heads.

It sounds like I may have missed a bolt only saw two but will recheck today. I am removing the cover that has the three hoses going to it. Is this the right cover for the thermostat?

G-man
03-21-2005, 12:58 PM
I don't think you have the correct cover. Should be top left front side triangle in shape.

Lance
03-21-2005, 01:24 PM
Should only have two hoses going to the cover... the two hoses go to the exhause manifold (right & left).

Lance
03-21-2005, 01:47 PM
I tried to find a picture in the forum that shows the triangular cover with three bolts. This is a good picture of it but unfortunately the thingy with the knob on it kind of covers it. Although this looks like it is a chevy engine (based on distributor location) you can still see the triangular cover that houses the thermostat. Basically follow the water hose from the exhaust manifold and you can't miss it.

http://www.tmcowners.com/photopost/showphoto.php?photo=969&sort=1&cat=501&page=1

rem_pss308
03-21-2005, 03:08 PM
Here is a pic of the housing with three bolts. It goes on the ford engine. ( 351) I am not sure about the chevrolet.

AirJunky
03-21-2005, 03:58 PM
It's on the '94 Chevy also. It's interesting.... when I went to change the thermostat the first time, I went for the housing below it. When I didn't find one in there, I opened the triangular one up & there it was.

jimmer2880
03-21-2005, 07:00 PM
Here is a pic of the housing with three bolts. It goes on the ford engine. ( 351) I am not sure about the chevrolet.

That's about what mine looks like on my '95 PS190 also (Not LT1).