After installing a 195F Thermostat my car runs hotter and I don't like it. What temp should I run? I don't know what temp was in there before?

derek2079

Member
Jan 21, 2020
29
7
13
Salt Lake City, Utah
A mechanic recommended running a 195F Thermostat so my cars heater would work better but it didn't change a dang thing except for now the car the run's hotter. Obviously Mustangs are known to run hot. I don't know what temp was in there before. But I want to run a lower temp thermostat so it doesn't overheat or get hot. Should I run a 160F?

Someone convince me of what temp thermostat to put into my car.
 
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08GT500

Active Member
Jul 12, 2018
612
75
38
Massachusetts
Hi,
Don’t have the specific’s on your Mustang other than it’s likely a 60’s-70’s, to be able to offer further insight, other than OE will work just fine. A 180 Deg T’stat will keep the coolant in the radiator a bit longer heater core may be partially obstructed or you may have a ducting issue, Fan output.
Happy to help further with specifics!
Best!
-John
 

derek2079

Member
Jan 21, 2020
29
7
13
Salt Lake City, Utah
I could do all of the guess work here or I could take it to a mechanic and I chose the latter. Car has new radiator installed along with 180F thermostat. Feels really strong. BTW I have a 67 4.7 289 2 barrel carb. I apologize for wasting your time.
 

08GT500

Active Member
Jul 12, 2018
612
75
38
Massachusetts
I could do all of the guess work here or I could take it to a mechanic and I chose the latter. Car has new radiator installed along with 180F thermostat. Feels really strong. BTW I have a 67 4.7 289 2 barrel carb. I apologize for wasting your time.
Hi,
Not wasting my time at all, not in the least bit- apologies if I came across that way, was not my intent, happy to do what I can (whatever that may be). 180 is what I’d choose as well, don’t think I ever ran a 160 in any Mfg’s motor pre-79’.
Heat’s not blowing warm much at all, or is it not at all?
-John
 

65ShelbyClone

Founding Member
Sep 9, 2000
4,601
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Antelope Valley, SoCal
Well yes the car runs hotter, you put a hotter stat in it! ;) The 195 isn't going to cause it to overheat, a lack of cooling is. The heater should be plenty warm with a 180° thermostat, so I suspect you have either a coolant or airflow issue involving the heater core. Does yours have a vacuum-actuated valve on the heater coolant line?

A 180 Deg T’stat will keep the coolant in the radiator a bit longer
Actually it will do the opposite, but velocity of coolant through the radiator has little effect on running temperature anyway.
 

08GT500

Active Member
Jul 12, 2018
612
75
38
Massachusetts
Edit: “A 180 Deg T’stat will keep the coolant in the radiator a bit longer”....added.to the comment VS a 160 Deg. T’stat with the situation that’s occurring.
 

08GT500

Active Member
Jul 12, 2018
612
75
38
Massachusetts
Derek...Did you find the issue with the heater core, clog within, fan, ducting, why it’s not blowing warm Heater temps?
-John
 

derek2079

Member
Jan 21, 2020
29
7
13
Salt Lake City, Utah
Well I didn't but I took it to a mechanic and he did. He also installed a new radiator and nowise running really cool. My problem now seems to be my battery keeps draining if I leave it sitting overnight. It's really annoying. I took it to one mechanic and he said my wiring harness was messed up and he tried to fix it but he said it may still need more work. I'm taking it to the mechanic I took it to last time and going to have him look at what's causing my battery to keep draining overnight.
 

08GT500

Active Member
Jul 12, 2018
612
75
38
Massachusetts
Hi Derek,
I don’t want to convey that I’m trying to interfere with any decisions you’re making, but paying someone to repair something that you can do, if you have the time & desire to, some basic tools. This is your 67’ 289- correct?
Do you have a handheld multimeter?
All it would take is one light bulb to stay on in the glovebox, trunk, hood, or even dash lights on at the lowest setting to be on, you’d not even see it, a stereo, or an Amplifier, even added gauge lighting, all may drain your battery overnight.
If your reverse lights were accidentally left on, stuck on, another commonly un-noticed issue, that would kill your battery.
If the Alternator is not recharging your battery fully, or if your battery has a low cell, it will discharge quickly. They test both for free at Advanced auto, Autozone. Maybe it had coolant spilled on it recently with the repairs and it affected wires or within connectors, or below it.
If there’s any wiring that’s in need of repair, you can easily do that, too.A great feeling of owning a muscle car is hat you repaired it. If you need help, just ask, that’s what this sites all about.
If you have your reasons for farming it out to another, that’s your choice.
Good luck either way!
-John