View Full Version : Ideal engine temp

Ralph Savarese
05-22-2014, 09:35 PM
What is the ideal engine temp you guys run at I am thinking 180 for FWC and 140- 160 for raw water ?

05-28-2014, 10:41 PM
If you are not running a closed loop cooling system, I would use the 140-160 thermostat to make sure nothing boils off in the water jacket. Fresh water is not necessarily clean.

05-28-2014, 10:45 PM
Misread your post. I agree with your raw water numbers and might go hotter with a closed loop system depending on engine vintage

05-28-2014, 11:45 PM
Roger on running a little hotter RWC vs. FWC. I have a 140deg t-stat and engine temp generally stays around 160.

I'd argue that water temp is a good thing to monitor, but not as important as oil temp, which tends to run a little bit hotter than the cooling system. Right now I'm keeping an eye on oil temp via a gauge mounted near the remote filter, because I don't have space on the dash for a gauge there. I like to see <200 the vast majority of the time, and maybe up to 220 after a really hard run. This is on good quality 20w50 dino oil that gets changed frequently. For $30 a little IR temp gun is a good way to double-check things, from oil pan to risers to senders to intake to trailer bearings.

You need to get the oil warm enough for long enough to burn off condensation; over-cooling is an issue, especially for the guys up north still breaking ice with their rigs. Overheating the oil is even worse and will kill the lubrication and eventually the bearings.

Here's a good chart I cribbed from somewhere on the interweb:


joseph m. hahnl
05-29-2014, 09:02 PM
What is the ideal engine temp you guys run at I am thinking 180 for FWC and 140- 160 for raw water ? I run a 160 in my full cooler as the temp spikes when your running WOT and come off plane. I've always done a little cool down run before I bring it into idle:yes:. Although now the 400 has a lot more aluminum then the old 350 mag and this season I added aluminum exhaust manifolds which should help dissipate the heat quicker:biggrin.: