Easy (I hope) thermostat q.

bauble

Registered User
So I'm about to replace the thermostat in my '93 SC and it occurs to me that while this sounds like an easy job, I've never done it before and I thought I'd ask if anyone can offer any hints or tips for a relatively unskilled newbie. Buddies I've talked to (shadetree mechanics) tell me this should be pretty straightforward, but think I may have to take off part of the supercharger.

If anyone can offer words of wisdom, they would be greatly appreciated.

bauble
 
its pretty straight forward--not much to take off
make sure you clean the gasket mating surfaces real well and be sure you
have the right gasket-match it up
also this will be a great time to flush the cooling system and put in new coolant
also you may want to use a 180degree thermostat
g/l
 
Why are you replacing it? You might check the old one when you get it out to see if its opening properly. I fought a..what i thought was warmer than normal..running condition and weird acting temp gauge for awhile. Finally ended up putting a new radiator in. That helped it, but SC's do run warmer, naturally. Others here can give a more technically experienced opinion.
 
You don't have to take off the supercharger. I usually take off the belt tensioner for the serpentine belt, it helps. Then I put a little loctite on the t-stat to hold it to the housing, let it dry. Then line up the gasket and put the bolts in, that way you don't have to worry about the t-stat sliding down.

It's not hard. It takes me about 45 minutes since I make my own gaskets out of gasket paper.
 
Get a factory t-stat from Ford for 2 reasons. 1 it turns and locks into position. 2 it has a weep hole that ends up on top to help bleed air from the system. Get yourself a manual. good luck
 
ironic, i did my t-stat tonight and came on to start a thread to debate what to do with the t'stat options. The oem one locks into place? Wow if it's not over priced, do that. that's the hardest part, getting the t-stat to stay in place when you try to put it in. I too used loc-tite to stick the t-stat in the housing and let it dry for about 10 minutes, this was the third try. First two tries it kept leaking because the t-stat slid down out of it's seat causing it to leak. So factory or loc-tite or something to overcome that. Also, the reason I did mine is years ago I did a 180 deg. t-stat, and have regretted it all this time. I believe that if your cooling fans and radiator work right, the 195 works just fine. My 180 has caused my car to never get up to normal operating temperature. Actually I'm suspicioous that the 180 in for a couple years may have actually aged my motor faster than it would have with the oem 195. So there my .07 or so cents worth!
 
The thermostat is a pretty easy change, I did not have to remove anything to remove the housing. There is one possible problem you could encounter while changing it: if your housing is at all warped, it will be impossible to seal! :eek: I replaced my housing with another used unit as new ones are 300 dollars now :rolleyes: . I used a FelPro gasket and no RTV, it still leaks slightly. I have found the Motorcraft gaskets to be better for this application, so I will be resealing mine with a Motorcraft gasket and some gray thermostat permatex RTV to hopefully seal it completely. Then again, it leaks so little I may just leave it, as its impracticle for me to service it anyway.

Hope that helps...
 
Oh, I forgot. Here's what else I recommend. There is a hose maybe 3/4" diameter that will be in your way. It's no big deal to get the tstat out of the housing with it in the way. Take the hose off before you put it back together and you'll save yourself a bunch of hassle. I bet more than one person has stripped a thread trying to put it back together with that hose still on which would be a huge hassle. To get the hose off, take a regular pair of pliers, slide it to the more open setting, grab the hose where the hose clamps were around the nipple and wiggle back and forth as to rotate the hose around the nipple. Once you break it loose it is easy to slide off. When I tried to put it back together with the hose in the way I slightly damaged the threads, causing me to stop, leave it apart, and get a tap from work the next day. I chased the threads with the tap and filed the screw clean in one spot, took the hose in the way off, and it went together like butter. Of course it still leaked the first two tries until I figured out how to get the t-stat to stay seated in the housing. Now that I know the right way to do it, I could do it in a half hour.

Also, digital chaos I'm surprised it would leak at all if the t-stat is seated right. Did you use the oem t-stat? If you didn't, like I said in an earlier post, if the t-stat shifts slightly when your lining up the housing to put it back together it will cause it to leak. There's no way to tell if it shifted once you start the screws, and trust me, that's when it shifts unless you held it in place with loc-tite or something(if not the oem t-stat), and then I was still very careful not to jar the housing. Also if you put the tstat in backwards it would cause it to leak but I'm guessing you made sure which way was right.
 
I removed it because it went bad...and I have no need for one down here!!..thats WTF I did it for!
 
I would ask around more about that sweet90sc. Even if your climate is hot, your car without the t-stat should take alot longer to get up to proper operating temperature. Now in the perfect world anybody would warm their car up fully before ever driving it because driving it cold wears the motor faster. Without a t-stat I suspect you are driving your car with a cold engine ALOT! Of course it's up to you, but that's just my thought on it. I just switched back to the 195 from the 180 for the same reason. and it does hit 100 up here in the summer time too.
 
You DO need a thermostat in warm weather!.. maybe even more than in cooler weather. The thermostat regulates the coolant flow, in extremely hot weather the coolant can flow throught the radiator so fast that it does not come out any cooler than it went in! .. remember, the radiator is simply a heat exchanger.....the coolant must remain in the radiator long enough for the air going accross the cooling fins to dissapate some of that heat. I'm in the northwest now but i grew up in Southern California and have seen this first hand. Especially with a tiny radiator like the SC has!.. Put your thermostat back in before it gets really hot!
 
Yea Shooter but it's a dry heat :D :D :D :D ...No I don't need a thermostat mines been out for 6 years..and the hotter it gets the less I need one..I grant you these radiators a riduculously small and crappy especially in the latter mods. But till the thermostat opens they are simply a large resavoir. Will it take longer for my engine to heat up? Yes. Do cold engines suffer more wear? Some. Is it significant enough to risk popping a HG next time my thermostat freezes up? No! My SC gets little or no driving in the winter and is always idled till warm. Yea if you live up north where it gets sub zero out in the winter time your crazy not to have a thermostat your heat will never work. Don't have any need for one here ;)....

175,000 mi orig HG's and no Thermostat...still going strong
 
kevenj90sc said:
You DO need a thermostat in warm weather!.. maybe even more than in cooler weather. The thermostat regulates the coolant flow, in extremely hot weather the coolant can flow throught the radiator so fast that it does not come out any cooler than it went in! .. remember, the radiator is simply a heat exchanger.....the coolant must remain in the radiator long enough for the air going accross the cooling fins to dissapate some of that heat. I'm in the northwest now but i grew up in Southern California and have seen this first hand. Especially with a tiny radiator like the SC has!.. Put your thermostat back in before it gets really hot!

Hmm, I don't think I agree with this as the reason to use a thermostat, although I agree that you always should. I know what you're saying, though. Let me tell you how I look at it, and you can comment on my thoughts.

The hot water going through a radiator will dissapate the most heat to the radiator if walls of the water pipe are kept as hot as possible. Slowing flowing water will be cooled by radiator and the pipe wall tempertaure will be hot where the water comes in and cooler where it goes out - on average. Faster flowing water will not cool as much, so the pipes throughout the radiator will be hotter. But, that's okay. The point is that the radiator pipes will be kept at a higher temperature with the faster flowing water, so more heat will be dissapated from the engine. I think that's really all that matters. The fact that there will be hotter water giong back into the engine doesn't matter.

That was a simple-minded way of lookig at it, and assumed the the water temperature entering the radiator is the same in both cases. It also assumes that the faster-flowing water has as-good conduction to the walls. I really don't know about that, but have some thoughts.

I do know that the thermostat causes more turbulent water flow, and that helps reduce the boundary layer in the water and aids in getting the engine heat into the water. This is another reason to run a thremostat in hot weather.

I have had several hot-running engines that ran hotter without thermostats than with. I never solved a hot-running engine problem by removing the thermostat.
 
Shooter_Jay said:
So factory or loc-tite or something to overcome that. Also, the reason I did mine is years ago I did a 180 deg. t-stat, and have regretted it all this time. I believe that if your cooling fans and radiator work right, the 195 works just fine. My 180 has caused my car to never get up to normal operating temperature. Actually I'm suspicioous that the 180 in for a couple years may have actually aged my motor faster than it would have with the oem 195. So there my .07 or so cents worth!

Shooter_Jay, I completely agree with your statement that "if your cooling fans and radiator work right, the 195 works just fine." But, if your engine never got up to operating temperature with the 180, then I'd say it was a bad thermostat. Let me tell you how I look at thermostats...

Thermostats should all stay closed when the engine is within maybe 5-7 degrees of the rating, then be wide open when they are about the same amount above the rating. I'd say the result is that you should have seen about a 15-degree drop in engine temperature under the same conditions with the 180 as you would with the 195. Maybe the temp gauge isn't so linear, though, and could have fooled you.

The engine should have warmed up at about the same rate with either, since they will both stay shut when under 170 degrees.

Not that you said anything about this, but a cooler-rated thermostat will not keep an engine from running too hot, either. Both a 180 & 195 will be fully open above about 205 or so.

My arguments about choosing the temperature value is that the manufacturers want the engine to run at a certain temperature. Running cooler or hotter isnt right, unless you know more than the engineers who designed it.

The ony reason to start playing with the thermostat value is to make up for something else not working right, which is what you mentioned - assuming that you're not racing the car, etc.

Let me know if you agree or not with what I said - they're just my thoughts.
 
jpetillo said:
Shooter_Jay, I completely agree with your statement that "if your cooling fans and radiator work right, the 195 works just fine." But, if your engine never got up to operating temperature with the 180, then I'd say it was a bad thermostat. Let me tell you how I look at thermostats...


[ Shooter_Jay ]

I wasn't convinced either way but it definitely ran cooler with the 180. What convinced me was running the koer test. Everywhere including the ford oem info says run it at 2k rpm for two minutes to get up to operating temp then shut off for 10 seconds then hookup then run koer. With my 180 it was never warmed up so it was tough to trust the codes. Put a new 195 in and the gauge is now out of the cold area right at two minutes in nice weather. Also I think temp gauge is a real gauge, not like the oil pressure which is like a 4 position idiot needle or something, correct me if I'm wrong.

I think your close, but logically, when the coolant gets up to 180 it kicks into the mode that cools it much more efficiently. My 195 will get to 195 much faster than my 180 is what I'm trying to say. If it was designed to run from 190-220, then you are running it under operating temp for longer. That's all I'm saying. Of course, maybe it's worth the trade-off because you're ambient temperature under the hood will be a little lower with the 180 I think.

Also I think they would have designed it to warm up until 5 or 7 degrees above minimum operating temperature before the t-stat opens. That's what I would have to do I think with my perspective as a machine designer.//


jpetillo said:
Thermostats should all stay closed when the engine is within maybe 5-7 degrees of the rating, then be wide open when they are about the same amount above the rating. I'd say the result is that you should have seen about a 15-degree drop in engine temperature under the same conditions with the 180 as you would with the 195. Maybe the temp gauge isn't so linear, though, and could have fooled you.

The engine should have warmed up at about the same rate with either, since they will both stay shut when under 170 degrees.

[Shooter_Jay ]
the 180 will start opening 15 degrees earlier than the 195 however you want to do the math.

jpetillo said:
Not that you said anything about this, but a cooler-rated thermostat will not keep an engine from running too hot, either. Both a 180 & 195 will be fully open above about 205 or so.



[ Shooter_Jay ]

and the 180 will be wide open to full coolant flow 15 degrees earlier than the 195 however you want to do the math.



jpetillo said:
My arguments about choosing the temperature value is that the manufacturers want the engine to run at a certain temperature. Running cooler or hotter isnt right, unless you know more than the engineers who designed it.


[ Shooter_Jay ]
yes, or unless you are looking to push the envelope more than the engineers to gain performance but maybe wear stuff out a little quicker or not.

jpetillo said:
The ony reason to start playing with the thermostat value is to make up for something else not working right, which is what you mentioned - assuming that you're not racing the car, etc.

Let me know if you agree or not with what I said - they're just my thoughts.



Half of your points argued my case for me. Who is this, John F Kerry?
 
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