Thermostat

[Stangman]

Probably around 200 but I don’t let it go over that. That would be in traffic not while it’s driving. It never actually overheats I just want it to cool better. My last motor it ran a little cooler. I guess another 75 horse and it’s running a smidge hotter. Maybe I’m just being to picky but if I can keep it cool it’s a win in my mind.

[jmlay]

If your seeing a max of 200 deg your well in the safe zone. I would not be getting concerned until it starts to head over 220 deg.

[My427stang]

If your seeing a max of 200 deg your well in the safe zone. I would not be getting concerned until it starts to head over 220 deg.

I agree with Mike

I also do not think a thermostat will help anyway, low speed overheating is generally air flow.  On a Mustang it could be fan/pulley sizing or exit airflow issues.  The Mustang shock towers don't help

[Rory428]

I've never heard of a 170 stat.  Factory is 195, and they're readily available in 160, 180, and 195.  The smallblock MOPAR (and others) uses the same large diameter stat so you might try searching Rockauto to see if something turns up there.

I have never heard of any FE engine ever coming with a 195 degree thermostat. Those may be common in modern computer controlled, EFI engines, but I would certainly never run one in an older carbureted engine, especially one that I wanted performance from. Between the increased chances of pinging, reduced performance, and obviously an engine running at 195 degrees is much closer to overheating than the same engine running at 170-180 degrees. Personally, I am not a big fan of aftermarket electric fans, I know to many people that have had overheating issues with them. There is a huge difference between an OE electric fan system, than the typical aftermarket stuff. Compare the size of the wiring and alternator output on a modern car with electric fans, to the wiring most aftermarket fans use.I have been running 160 thermostats in my FEs for close to 50 years, and my current 428 CJ also has one, and with an aluminum 2 row (1 1/8" tubes), with a 7 blade 18" mechanical fan, and driving down the road in usually runs 165-170 degrees, maybe a touch higher on hot summer days. If I get stuck in a gridlock situation for 15 minutes or more , on a warm day, it can slowly climb up t about 200, but goes back down pretty quickly once moving again. I have had it idling for over 1/2 hour on a hot summer day, and it has never overheated.

[fitter]

As usual. Spot on real world input from Rory. I’ve followed his comments on here for awhile and find his input to be of great value .

[Stangman]

Rory is that 18 inch fan a clutch fan. And are you running a shroud. Is it the original type radiator or switched over to a crossflow

[66FAIRLANE]

If your seeing a max of 200 deg your well in the safe zone. I would not be getting concerned until it starts to head over 220 deg.

I agree with Mike

I also do not think a thermostat will help anyway, low speed overheating is generally air flow.  On a Mustang it could be fan/pulley sizing or exit airflow issues.  The Mustang shock towers don't help

Just as an example on the effect of pulley size. Someone gave me a nice looking aluminium water pump pulley. It was about 3/8 larger than the one that was on there, it just fitted. When I tried it there was an immediate and quite noticeable rise in idle temps. Removed it immediately. Was it the fan speed drop, pump speed drop or a combo? Dunno, but I was very surprised how little of a change made a significant difference.

[Jb427]

Stangman what do you use to trigger your fans?

Do you use a electronic fan switch mounted in the manifold or radiator thermostat housing? link here of what I am talking about https://www.summitracing.com/parts/sum-890117

They come in many temp ranges you can check exactly what one you have with boiling water thermometer and a multimeter I would use one with 170 to 180 range = fan come on @ 180 and fan turns off @ 170

I think your getting lost in the thermostat temp.  Thermostat temp 160 170 180 only lets the water flow at that temp.

160 thermostat and electronic fan switch 170 to 180 range for a warm to hot climate is what I would use in any of these type of cars/engines
 

[My427stang]

In stop and go traffic the engine isn’t making any power, so really not generating a lot of heat, although if your initial timing is a little low it can heat things a little bit

What is happening is you are losing airflow under the car and into the radiator, which is why they get warm, both help cooling air flow

If you cannot add fan volume with speed or fan size, you could try to add a couple degrees initial, and/or you could try a 160 thermostat, but as I said I think it’s airflow

Been there with mine too

[Rory428]

Rory is that 18 inch fan a clutch fan. And are you running a shroud. Is it the original type radiator or switched over to a crossflow

No, the fan is a stainless steel Flax A Lite 18" 7 blade HD model, and no shroud, as 59 Ford cars never came with them. And it is a stock style "up and down" style radiator. Many years before, I ran the exact same model fan , (with the factory fan shroud), in my 70 428 CJ Mach 1, with a 160 thermostat, with similar results, using the factory CJ radiator. And on my old 69 428 CJ Mach 1, the factory clutch fan, shroud, and radiator also worked well.

[Stangman]

If your seeing a max of 200 deg your well in the safe zone. I would not be getting concerned until it starts to head over 220 deg.

I agree with Mike

I also do not think a thermostat will help anyway, low speed overheating is generally air flow.  On a Mustang it could be fan/pulley sizing or exit airflow issues.  The Mustang shock towers don't help

Just as an example on the effect of pulley size. Someone gave me a nice looking aluminium water pump pulley. It was about 3/8 larger than the one that was on there, it just fitted. When I tried it there was an immediate and quite noticeable rise in idle temps. Removed it immediately. Was it the fan speed drop, pump speed drop or a combo? Dunno, but I was very surprised how little of a change made a significant difference.
I do have a smaller water pump pulley from CVF. It did make a difference over the stock pulley

[Stangman]

Stangman what do you use to trigger your fans?

Do you use a electronic fan switch mounted in the manifold or radiator thermostat housing? link here of what I am talking about https://www.summitracing.com/parts/sum-890117

They come in many temp ranges you can check exactly what one you have with boiling water thermometer and a multimeter I would use one with 170 to 180 range = fan come on @ 180 and fan turns off @ 170

I think your getting lost in the thermostat temp.  Thermostat temp 160 170 180 only lets the water flow at that temp.

160 thermostat and electronic fan switch 170 to 180 range for a warm to hot climate is what I would use in any of these type of cars/engines
 

Like I said as of the moment I don’t even have a thermostat in there couldn’t find my old one and my parts store was closed it was a Sunday. But yes I do have that same switch. When I was running the 180 thermostat I had a switch that turned on at 190 and shut off at 175 although if it was hot out it wouldn’t shut off but would stay somewhere around 187-190 which is fine unless I get stuck in traffic.
Now with the new motor I had tried a 160 stat and a temp switch of I think 175 on and 160 off. And if I don’t get caught in traffic or if it’s not brutally hot it runs about the same as the other set up 185-190. I want to be able to drive in any weather.

[Stangman]

Rory is that 18 inch fan a clutch fan. And are you running a shroud. Is it the original type radiator or switched over to a crossflow

No, the fan is a stainless steel Flax A Lite 18" 7 blade HD model, and no shroud, as 59 Ford cars never came with them. And it is a stock style "up and down" style radiator. Many years before, I ran the exact same model fan , (with the factory fan shroud), in my 70 428 CJ Mach 1, with a 160 thermostat, with similar results, using the factory CJ radiator. And on my old 69 428 CJ Mach 1, the factory clutch fan, shroud, and radiator also worked well.

Years ago I had a steel fan it was a stock one I don’t know where my dad got it I think it was a 7 blade fan. It would still do what it does now. I’ve been a temperature gauge watching driver forever.
Boy wouldn’t it be nice to not have to watch it all the time.

[Stangman]

In stop and go traffic the engine isn’t making any power, so really not generating a lot of heat, although if your initial timing is a little low it can heat things a little bit

What is happening is you are losing airflow under the car and into the radiator, which is why they get warm, both help cooling air flow

If you cannot add fan volume with speed or fan size, you could try to add a couple degrees initial, and/or you could try a 160 thermostat, but as I said I think it’s airflow

Been there with mine too.
My initial is already fairly high. I keep it between 22 and 26, I do think it’s air flow and maybe not enough fan speed. I do have an electric pump and a dual fan setup and my alternator is a pumped up 55 amp which is around 70 now. That is another thing that will be getting upgraded. At idle with fans on you can hear them spin a little slower which could also be a part of this problem. I do believe with my new setup and a bigger alternator it’s gonna be better.

[My427stang]

I ended up running an 18 inch Flexalite clutch fan and 5555  clutch with a  aftermarket shroud and ceramic coated headers  However, what made the biggest difference sitting in traffic was the Boss 9 scoop.