1997 Roadtrek on Dodge 2500 chassis with 318ci engine, 140K miles. Drove down from NJ to FL. Engine temp usually runs around 198 degrees. Noticed that when we entered Georgia and the temps were in the 80s to 90s, that the engine temp ran a little warmer. When we got to Florida after a six hour run, the engine temp seemed to climb to 200-204. When pushed, the temp would climb then cool back down to 200-204. Is this normal or should I begin having the cooling system checked. In my mind, cooler operating temperatures translate to longer life and that is my goal. Thanks for your input.

 

You're driving in a more humid environment. I'm from Death Valley and the only time that my 1977 B150 Tradesman van with a triple core radiator overheated was coming across Lookout Mountain in southeastern Tennessee. Very humid.

 

So you are saying that because of the high humidity my engine temperature is normal? V c4

 

VERY humid environments = much hotter running temperature. Yours is not normal but don't allow the motor to run at an elevated temperature for too long. Hell, mine ran elevated at 5300 ft elevation in the Calif. desert near Darwin for a hour or so while trying to dig it outta' a hole. Not a problem thereafter. If the temp gauge goes full max for an extended period of time then imho you might have a problem down the road. In your case don't worry.

 

The Dodge book (FSM, 1996) says the thermostat is closed below 88C (192F) and is designed to provide a minimum operating temperature of 88-93C (192-199F). The thermostat should be fully open at 104C (220F). This is a bit warm to my liking. Looks like thermostats rated 195F, 180F, and 160F are available.

 

The thermostat recommended for my '77 318 Dodge van was 192F. When a lower rated thermostat was installed, the motor suffered. It failed to produce full power. So I would recommend using the manufacturer's recommended thermostat for your vehicle. Consult the FSM for the recommended thermostat.