Engine coolant temperature

[phorner]

We will be travelling in the Southwestern states this summer and I was curious about engine/transmission temperatures.

Anyone have "normal" running temperatures or recommendations as to what would be considered "high"?

Also, I've noticed in the past that using the OTR air conditioning will add 5 degrees or so to the coolant temp. Is this about right?

Comments/past experiences would be appreciated!

[garyde]

Hi Paul. I'm about 185 on the Engine, and 205 on the transmission. I would check with Detroit and Allison also.

[rfoster]

Paul on the way to Mobile, my tranny temp ran from 200 to 214, mostly at 206, engine from 189 to 198 mostly 194, variables depend on speed, and ac on or off and outside temp changes.

[hhoppe]

Paul: Running in the western states you will encounter more mountains/hills than usual. Use of your transmission retarder will come into use often. As a precaution I changed the Allison Trans. fluid to "Transynd" to help control the overheating and add longer periods between changes. Jon has had info on temperature controls on a previous post. The upper right oil temp guage gives transmission temperature at a oil transfer point and elevates when the retarder is used. That does not mean the total transmission oil temperature is elevated to the numbers shown. An average temp. shown between ret. use will be more accurite for the total oil capacity. Use the retarder to control a safe acending speed, drop to lower gears to represent a safe speed. Do not pump the brakes off and on, rather apply them light and steady to maintain your safe speed. Don't be intimidated by following trraffic to increase speed. You will let them pass when it's safe to do so. I know this is more info than you asked for, but hill driving can be intimidating when you first encounter it.
As far as engine temperature rise, you will want to turn off the over the road compressor on long uphills and then back on for comfort. Your Liberty will handle the Southwest really well.

[0533]

I noticed that when descending steep grades my Jake Brake was defaulting to six gear. the only way I could adjust for the increased speeds was to manually lower the gears, which works OK.

I had the transmission default changed (computer 5 minutes) to 5th gear which now offers some real jack Brake action, before it was almost useless.

I find that when running down the interstate on level ground, I turn off the the Jake, only turn it on at intervals 1 and 2 when in close traffic or heading down grades.

I also changed the transmission oil to "Transynd" noticed a lowering of the temps right away.