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John Barilaro
Red Sox Nation!
(60 posts)

11/02/2007 08:29AM

Main British Car:
1977 MGB Ford 302/5L

Ford 302 (5L) Thermostats
Posted by: jbarila
Date: March 27, 2008 01:10PM

What have the 302 users found to be the best temp. range for choosing a thermostat? Stock was 192 deg. but as far as performance is there any advantage to using a 180 or 160 degree.
Thanks in advance.

Curtis Jacobson
Portland Oregon
(4476 posts)

10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

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Re: Ford 302 (5L) Thermostats
Posted by: Moderator
Date: March 27, 2008 02:20PM

I don't "use" a 302, but... my vote would be "doesn't matter much". Here's my thinking:

These thermostats all open up to the same cross-sectional area, don't they? And don't they open fully once they get to their rated temperature? So, the way I look at it, they don't really govern the operating temperature of the engine in normal use. Regardless of which thermostat you pick, I expect your engine will probably run between about 195 and about 205 degrees (at the coolant temp sensor), except during warm-up and in very cold weather.

Any thermostat should help your engine warm up quickly by keeping the radiator switched "off" until it's needed. (Warming up quickly is a good thing, primarily because cold engines wear quickly and pollute more.) For that reason, I personally would stay away from the 160 degree thermostat. 160 degrees is way below proper operating temperature.

Thermostatically controlled cooling fans can be used to fine tune the normal OPERATING temp of an engine, but IMHO that's not normally a job for the coolant thermostat.

Generally though, engines make more power when they run a little warmer, assuming they're tuned to take advantage. (It doesn't worry me at all to see gauge readings top 210. I kinda think of "215" as a lucky number. Above that....)

V6 Midget
Bill Young
Kansas City, MO
(1337 posts)

10/23/2007 09:23AM

Main British Car:
'73 MG Midget V6 , '59 MGA I6 2.8 GM, 4.0 Jeep

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Re: Ford 302 (5L) Thermostats
Posted by: V6 Midget
Date: March 27, 2008 04:10PM

John, I'm another non 302 person, but my experience over the years shows that thermostat temp in relation to engine performance is somewhat dependent on the components on the engine. I wouldn't recommend anything below 180 degrees, I prefer the 190-195 range which usually gives good fuel vaporization in the engine as well as a bit of "cushion" before you reach the boiling point of your coolant. Oh yeah, coolant type will also impact your decision, if running plain water go a little lower than if running a coolant that will raise the boiling point. If you are running fuel injection with the stock computer then changing the thermostat could throw things out of balance, stick with one close to the original setting.

Graham Creswick
Chatham, Ontario, Canada
(1113 posts)

10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

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Re: Ford 302 (5L) Thermostats
Posted by: ex-tyke
Date: March 28, 2008 01:13PM

FWIW, I run a 180 degree stat in my carburetted 302. With the temp sensor located in the stat housing, the temp gauge is typically operating at the "N" position (whatever number that is?).
Late model FI engines typically have a 190-195 range per the comments above but, for my piece of mind, I like the additional temperature buffer that the 180 offers.

kelly stevenson
Southern Middle Tennessee
(943 posts)

10/25/2007 09:37AM

Main British Car:
2003 Jaguar XK8 Coupe 4.2L DOHC/ VVT / 6sp. AT

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Re: Ford 302 (5L) Thermostats
Posted by: kstevusa
Date: March 29, 2008 02:37PM

As Graham indicates, the 180 gives a little more "wiggle room" than a 190-195. the Ford Mustang boards, either is OK. The general opinion on 160, Too Low for Computer cars and probably carb'ed also. In my EFI car, i run a full flow Mr. Gasket 180 stat. the fail safe ones are only good for one cycle and then have to be replaced. you may only find this out when cold weather arrives, don't ask how i know.

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