View Full Version : Thermostat questions...

02-27-2007, 08:31 PM
Well just being bored at work i checked what the OEM temp is on a 89 SC's t-stat and its 197 degrees..that seems crazy high to me. I had a 175 degree t-stat on my Lightning and never had a problem with it..even in cold weather. What are some of the t-stat's you guys are running and does anyone have a stant part number or something so i can pick one u from one of the local parts houses. All we/Ford lists is a 197. ALso any problems with the t-stat housing cracking....just so i know when i get it off.

PS...have any of you tried Red-Line water wetter coolant additave? JW



Scott Long
02-27-2007, 09:07 PM
Don't go colder than 180 or you will need to tune for it. I had 160 in my car, ran like crap, rich all the time, wasted a lot of fuel, down on power.

02-27-2007, 09:08 PM
OK cool..thanks for letting me know. I gues sno point in trying to find a 185....maybe i will give the redline water wetter a try.

Scott Long
02-27-2007, 09:19 PM
You can get a 180, 160, and 195 for the car from most parts stores. I just wouldn't go below a 180. Even with a 180 you'll need to get the fan to come on sooner to see any difference in engine temp. I'd cut wire 14 on the IRCM, thats how mine was for years. Makes the low speed fan run with the key on. Keeps engine cool.

Now I have mine fan on a switch w/ a 30 amp relay on the low speed side. It rarely gets hot with a 195 in it, but if it does I flip the switch.

02-27-2007, 09:47 PM
OK cool...that should really work out well when i move to florida. lol

02-27-2007, 09:54 PM
I used a 180 super stant from advanced auto parts.And I use 2 bottles of water wetter it seems to run cooler in the summer but I can't give you a temp decrease number because I'm still using the stock gauge.I also have a aftermarket fan from Vic at spinningwheels.com.Car runs cool and so far I haven't had any drivability problems in summer or winter.Hope this helps.


02-27-2007, 10:06 PM
i got a 180 thermostat from MR GASKET, bought it from summit, 10 bucks i think, its a pretty cool design, allows for more flow when it opens, and it opens withing a degree or two of the set temperature and opens despite coolant pressure.... works for me!

02-27-2007, 10:07 PM
Well, here's what I've done to all three of mine.

Thoroughly drain and flush the system
Mix up a blend of 25% ethelyne glycol (the good stuff, not that environmental crap) and 75% distilled water
Add 1 bottle of Red Line Water Wetter
Install 180 deg. thermostat
Dump in the mixture and top off as needed until stabilized

Never had any overheating problems. In San Antonio. In the summer. In traffic. Period.

However, all three have extremely clean cooling systems; no residue. Plus, I installed a new radiator, and GM (taller) chin spoiler on my titanium car (driver). However the white car and Cougar are totally box stock original.

You can easily get by with the weak E/G blend in the south. I'm toying with going to 15% E/G - 85% distilled water next time. Basically, I'm only using E/G to control corrosion. If you live up north, then you can substitute a 50%-50% blend.


02-27-2007, 10:21 PM
Thanks TX..really great info to know.

02-27-2007, 10:29 PM
Thanks TX..really great info to know.

One more thing; I'm fixing to buy new Motorcraft radiator caps for all 3 cars. That's probably a good idea for you, too. If they're not IDENTICAL to the originals, then I probably won't bother on my white car, since I don't drive it anyway. I'm sure they'll at least be good enough for my drivers. I just can't stand the looks of the parts-store aftermarket radiator caps. But that's just me...


03-04-2007, 11:42 PM
Yeah i always try and use as many Motorcraft parts as i can for tune/maint. stuff. Working at a Ford dealer in parts helps though. I know the stuff is going to be right and what i want because i look it up lol