Thermostat . What temp. is best ?

damoldford · #1 03-14-2012, 09:06 AM

What would you say is the best temp. OME says 195 ( I am told by my NAPA dealer ) I am thinking 180 may protect my heads from cracking and just cooler is better . Am I cracked in the head for this thought ??

FireRanger · #2 03-14-2012, 09:42 AM

195 is what the engine is designed to operate best at. Running at 180 would have you 10 degrees below normal operating temperature. This is probably not going to create a measurable performance issue, but it is none the less not the designed operating temperature.

Wrecking the heads takes extreme repeated or continuous overheat conditions. If something is causing severe overheating, a lower thermostat setting is not going to change that.

damoldford · #3 03-14-2012, 11:11 AM

Thanks for your in put Matt . What I didn't include in my post is that this truck will be working a bit harder than normal in that I use it as a service truck in my contracting buz. and it carries heavy loads ,well heavy for it any way !

Fightinirish157 · #4 03-14-2012, 11:22 AM

Loads don't really matter...it your are overheating the truck there is an issue...running the truck at a lower temp isn't going to do anything to help it.

Or it could be you are overheating the truck cause you are overloading it in that cause you need to get a truck that is capable of what you are doing or make more trips with smaller loads...or a trailer and it might take so of the load issues off.

damoldford · #5 03-14-2012, 12:03 PM

Loads don't matter ,, what are you thinking ?? The harder the motor is working the hotter it will get ! I have been using trucks for work going on 40 + years and I've seen more than a few over heat ! And PS Pulling a load isn't any easier than carrying one ! But thanks for the input none the less

Fightinirish157 · #6 03-14-2012, 01:57 PM

If you are not overloading then you should not over heat...

FireRanger · #7 03-14-2012, 05:02 PM

The reality is that normal operating temperature is a RANGE. The thermostat simply controls the LOWEST the temperature will be allowed to drop. The thermostat's job isn't to prevent overheating. It is to prevent overcooling.

When the outside temperature is below around 80 degrees, the ram air through the radiator while moving (or the fan while not moving) is enough to bring the coolant temperature well below the minimum (195, or in your case 180). The thermostat closes to prevent that from happening. Therefore, the coolant temperature ends up hovering right at the setpoint.

When the outside temperature climbs higher than 80ish, or you're putting a heavy workload on the engine, the coolant temperature will generally start climbing higher than your thermostat setpoint. 200-220 is very normal for very hot days. Even cruising along with a 75mph wind blowing through the radiator, the temp will climb. It's perfectly normal for that to happen. The thermostat is wide open at around 200. It can't do anything more. So as you can see, a thermostat with a lower setpoint will have absolutely no effect on high temperature.