It's 85* today so I decided to go up my test mountain for the first time since I reworked my entire cooling system in the winter.

The elevation gain is about 5000ft, avg grade of 6.5%. I had my scangauge II connected and noticed that on a few spots, I was getting up to 225*. The efan was coming on as it should. The temp would go down as the grade leveled off and I could speed up, but once I did use the heater to cool it down during a particular long climb.

Also, my a/c was off and I was in 3rd gear the whole trip up the mountain. I can drive 75-80 in this temp (w/ ac on) for as long as I want and my coolant temp stays around 206*. Driving around town (85* outside temp) with ac on will see me get up to 211-215* on occasion.

I have a CSF 2 row alum rad, mopar tstat, mopar rad hoses, gates water pump, hayden stock clutch fan and stock efan. Coolant is clean and green. I did the same mountain in the winter (30* outside temp) and it never got above 210*.

Was I just putting a lot of stress on the vehicle? What is left for me to try to reduce the temps on long hills during the summer? Or is this just what I should expect from a 15 yro vehicle?

Thanks.

 

^^^^^^^^The variable is the driving conditions. The constant is the condition of the cooling system (all new). Any vehicle out there with a accurate digital temp gauge will show the same thing (driving in 85 ambient vs 30 ambient, driving up an incline vs level ground). Factory gauges r purposely designed/rigged to basically point to the middle when all is good. A digital gauge, such as your ScanGauge that's displaying what the ECU is seeing, tells u "like it is". Under extreme driving conditions, our ScanGauge has momentarily peaked at 230F (we also have a new cooling system).......factory idiot light even flickered.

 

I understand. I used the same scanguage back in the winter as well. I have not IR gunned the engine to see if the scanguage+coolant temp sensor is accurate. (The coolant sensor is mopar and installed recently too.)

Is this what I should expect? 225* on a hot day going up a steep incline at around 35 mph? That seems toasty to me, especially after all the work I've done on my cooling system the past few months.

 

I would say perfectly normal for the XJ. The weak link in the XJ cooling system is the dinky surface area of the rad core (27" X 11"). The XJ rad, regardless of who makes it, is a pathetic 1.25 sq. in. per cubic inch displacement. Our other vehicles, both 2 & 4 wheel, have rads at 2+ sq. in. per cubic inch displacement and one has a rad with 3 sq. in. per cubic inch displacement.

 

This is very true. Even when I was at 225*, the factory gauge was still on 210* (albeit slightly more rightward than normal.)

 

I'll give u a example of both factory analog and digital gauges. We've got an '05 Buick LeSabre 3.8L Series II V6 motor. It has a analog temp gauge with a "C" at one end and a "H" at the other end. It also has what GM calls a "DIC" (LOL) or Driver Information Center. In 3 digit weather, stopped in traffic, a/c roaring, I've seen the "DIC" display 230F but the gauge needle still points dead center no matter what. Below the 230F number display the "DIC" also displays the word "NORMAL".

 

Thanks for the replies. I guess I'll keep an eye on it during long hills. I am thinking about a tranny cooler now or perhaps putting in another stant tstat and switching back to mopar next winter. The last 195* Super Stant I had actually kept the engine a bit below 195*...

 

Keep that ScanGauge plugged in, it's your truth teller/friend. Tranny cooler is always a good idea, IMHO. FWIW, we run a 180 Stant year round. It will run cooler in 30F ambient with a 180 vs a 195. In 85+F ambient it (the XJ) will run a little cooler, a little longer than a 195. In harder driving conditions for extended periods of time, a 180 will not run any cooler than a 195.