Thermastat

[sedanman]

Hey everyone,

Hope everyone had a nice Thanksgiving. I bought a 16 inch spal fan for the 36 chevy with a fixed fan switch at 195 degrees. What thermastat should I run? I was thinking 195. Its a small block from an 86 camaro. I am running A/C. Its a 700R4 trans.
:?
Vic

[40]

That's what I run in my cars......anything cooler and I've been told it decreases engine efficiency.My cars usually run right on the stat temp.

[sedanman]

Thanks 40  

[Learpilot]

I run a 180 just because that is what the 68 350 came with. Should I change to a 195 ? I have a Super Cobra radiator by Walker in my 36 Dodge. I have a mechanical fan and have had no cooling problems so far even at 100 degrees with the A/C on. How much more gas milage do you get by going to a 195 from a 180 ? Or is it because it just runs better ?
Thanks, Rick Harris.

[Dave]

Ive used 180 in all my cars and ive got a spal on the coupe with an adjustable t-stat. I never found the fixed ones to come on at the ratings?
Dave

[enjenjo]

For a carbureted car, 180 is fine, but if tuned properly, and the cooling system will take it, you can get up to 5 percent better mileage, and an increase in HP with 195.

Most electronic fuel injection engines are calibrated at 195 degrees.

[sedanman]

This is a carb engine. My concern was if the fixed fan switch turns the fan on at 195, if I go with a lower temp thermostat (say 180) will the fan not come on at all or only when the the engine reaches 195 with the lower temp stat open? Does that make sense? Would it be better to match them or run the 180 stat with the 195 fan switch? Or change the fan switch to a lower temp also?

Vic :?

[Mikej]

The fan shouldn't run at highway speeds. So you do want the fan to come on at a higher temp. The problem with the fixed temp. stat is where it is placed and what the temp. of the water is there vs where the temp sensor for the motor is. With an adjustable fan stat you can set it so it doesn't come on on the highway but will come on in town. I had a fixed stat in the bottom of the radiator in my car and the motor would be 230 deg. before it would come on. Bad.
I think the 180 deg stat would be just fine. If you are running any HP it will be better with this cheap gas with get.
The after market parts aren't designed for a specific car so I believe you should use the adjustable stat so you can fine tune it for your car.

[alchevy]

I have one of those Spal units to turn my Spal electric fan on at half speed at one temp, then turn on at full speed at a higher temp. Both temps are set at the factory, but you can customize it to your liking. See the picture of my gauge. I am trying to figure out what the temp is where the red arrow is at on this VDO Cockpit Royal temp gauge. Spal tech support told me that the two temps have to be 25 degrees apart from each other. I don't have mine that far apart, so it just turns the fan on at full power instead.

[sedanman]

That looks like the same gauges I have. Mine are not hooked up yet. I'm getting to that point though. It looks like you are pointing to about 150 to me. Just my guess.

Vic

[EMSjunkie]

I have the adjustable fan controller from Speedway on my Coupe.
it works really good. simple install too, uses your existing temp. sending unit for your temp guage.


Vance

[sedanman]

Vance, I think I bought mine from Sprinfield Streetrod parts about 2 years ago. I am just now to the point of putting it on. I can't remember now why I went with the 195o fixed.... read: (CRS) but I did. Its to late to return the switch now so I want to try to make it work. From the answers so far, am I right to say I should go with a 180o thermostat and the 195o switch so that the fan will not come on at highway speeds? The sensor for the fan switch is mounted in the stock location in the head.

Vic

[40_Tudor]

I talked to the PRC radiator sales guy at Goodguys Columbus, when I ordered my radiator for my 40 Tudor a couple of years ago, and he said you don't get an accurate reading with the temp sensor in the radiator. He recommended use one of the holes in the head where the factory sensor is located. The heads heat up way before the radiator tank does.
Also modern engines are designed to run better hotter, ~ 200deg.
Also how accurate is your gauge? You might want to double check it with another style gauge or use a good laser temp gun.
My 2 cents.