Is my thermostat ok

[guevara42]

Im running a 160* thermostat on my 66 mustang with a ‘92, 302 engine. The engine is freshly rebuilt. I live in Florida and temp runs at 190-195. Gets a bit warmer in the highway. These are summer month temps. I have a 2 row champion radiator with a shrouded electric fan and a/c. IN the winter, it runs at 160-175*. Seems a bit cool. What temp is “normal” and what thermostat should II throw in it? Thanks!

 

[MustangIIMatt]

Im running a 160* thermostat on my 66 mustang with a ‘92, 302 engine. The engine is freshly rebuilt. I live in Florida and temp runs at 190-195. Gets a bit warmer in the highway. These are summer month temps. I have a 2 row champion radiator with a shrouded electric fan and a/c. IN the winter, it runs at 160-175*. Seems a bit cool. What temp is “normal” and what thermostat should II throw in it? Thanks!

If your coolant temperatures are staying below 200 degrees, you're fine. Older engines run about 180-200. Your 160 thermostat would be an issue if you were running EFI or were in a colder climate. For what it's worth, I run a 180 in my Mustang II in Texas with a 302 bored .040 over, but I'm also running a 3-row aluminum radiator, the biggest electric fan I could shove in there, and no A/C. It runs between 180 and 210 on 105 degree days.

 

[7991LXnSHO]

The 160 deg thermostat is not helping the engine stay cool in the summer. Once it reaches 160, it just stays open. A 180 would help heat and to reduce wear in the winter without changing the summer cooling.
Getting warmer on the highway points to air flow problems. Adding an air dam under the radiator core and making sure the seals are around the radiator are first steps to take.

 

[guevara42]

Thanks guys! I will remove my 160* thermostat and replace it with a 180*. We’ll see how it does.

 

[7991LXnSHO]

If you do change it, be sure to get the full flow type. This one is the brand and style I use if given a choice. The picture shows they are not the typical Stant design that can close under high rpm flow and pressure.

https://www.summitracing.com/parts/bra-330-180

I do not think that the thermostat will change much in the summer (unless it is not opening fully at RPM), but your defroster and heater will work better this fall and winter and your oil will have less blow by water and unburned fuel in it.

Since you are going to have to drain at least some coolant, try adding some “water wetter”. It’s a surficant that helps with heat transfer. It has been helpful in tractors and cars for a very long time, and is not snake oil.

https://www.summitracing.com/parts/red-80204

Did you check for air gaps around the radiator and look into a lower air dam already? If your water pump is good, the lower radiator hose is not collapsing, and ignition timing is not off, that’s the next reason for running hot on the highway.