what are the standard operating temps for a factory thermostat? I'm used to running 185-195 with the 180 degree and wanna know what to look for with the factory temp in there for the time being.

 

I've had temps on my 2001 Disco get up to 221 degrees with a stock thermostat. HOT!

 

When I had the standard thermostat in my truck temps were generally in the mid 190s, sometimes up to around 200.

There are a lot of people on the forum who, in my opinion, are paranoid about temps, plus I think there's a lot of misunderstanding about the function of the thermostat.

Unless the thermostat is stuck closed or near-closed a new, 180 degree thermostat won't do anything to make a truck that runs 210-220 run cooler. Once the thermostat opens it's open. After that it's up to the radiator and fans to keep the coolant temp where you want it.

A little over a year ago my son called to tell me the truck overheated. I happened a couple of miles behind him on the same road so I had him wait for me. I expected to find the reservoir empty but the coolant level was where it needed to be. Radiators don't plug that quickly, and the pump was fine, so that meant it had to be a stuck thermostat, and it was.

I think some trucks just run hot. A friend had an '04 that ran at 210-215, even at cruising speeds, despite a new radiator, pump and thermostat. Yes it was the standard thermostat but as I said, once it's open it's open and it's up to the radiator, pump and fans to do the job.

I'm happy that my truck now cruises in the upper 180s and idles in the mid-190s, but I also don't know that running 200-210 is a problem. Remember, the auxiliary fan doesn't even start running until 212.

 

when i had my stock stat in i was at 197 to 199 on the highway, and at idle it seem to stop around 206. the 180 stat in now for the last year, just got a glow shift gauge installed and the glow shift in deed shows 180 on the highway and will get up to 194 if idled for a while. torque app shows about 10 degrees hotter then the glowshift gauge. most likely do to the glow shift getting temps from fluid in the hose above the fan and the obd2 ports reading from the sensor on the upper manifold. would be nicer to get the glowshift sensor closer to the OEM sensor location.

agree, the fan will not turn on till at 212 so im not to worried if the temps climb to around that point. i had mine up to 210 last year, but i was just sittin in a parking lot watching the temps climb slowly. when in normal driving conditions and even in heavy traffic here in Dallas it sits around 200 more or less.

the OEM stat seems to not have such a large range of temps like the 180 soft spring will. 197 to like 206 and then the soft spring doing 183 to 204.

 

Yes! That's my point!

The thermostat controls the lower end of the normal operating range but does nothing to affect the top end of the normal operating range.

So of course, if your radiator and fans are capable of keeping the truck not higher than around 200° but at cruising speed the thermostat stays open to a lower temperature the range be wider for the 180 thermostat.