joem

old 5.9 12v guy here picked up a stock '11 longhorn in mint condition, how hot is normal? Empty I see 190's but pulling a 10k pound trailer up a 6% in 5th @ half throttle holding 60mph on a 90F day the clutch fan came on around 220F then at 230F I herd clunking in the heater core- went back down to 200F the second I started down the back side of the hill. the dash gauge never reached red, just stayed around 3/4 when the MFI showed 230's --Just curious.
Thanks guys, Joe

New2Diesel

FMB

Hey Joe, sounds like you have an air bubble in your cooling system. You'll need to manually bleed that out.
back to morning brew . . .

joem

I'll try that- all my friends got me worked up thinking head gasket and all...…

C Schomer

My new to me 118K mile 2012 ran hot until I washed about 30 lbs of bug mummies out of the front coolers. Now it runs up to 200 water and 178 trans, even towing. Craig

tobyw

I will see typically anywhere between 199-204 just running around empty, and I've seen 220 for a few seconds before the fan kicked on and cooled it back down to ~205 when I was pulling heavy (43' toy hauler loaded to the brim).

dewclaw

I had a '99 and I ran a 192 deg thermostat in it . When I got the 2010 i noticed that it runs 199-203 f on average . My assumption was that they raised the temperature to get better emissions. I think that is a strong possibility. I have deleted stuff in my 2010 and have been thinking about putting a 192 deg stat in it .
Why? #1 extra heat is not good for the engine overall #2 oil life is reduced with higher temperatures. #3 it makes the tranny run hotter .

Could it be that they are running the motors hotter now to make the EPA happier ? At the expense of our engine life ? I had 415k miles on my last CTD and would like to get that much out of my 2010, running it cooler might help me to achieve that .

ANY THOUGHTS ?? What would the downside be of running a little bit cooler T-stat?

Dew

dewclaw

After some web searching about my last question. ....,my question seems to be answered. Going to a lower temperature stat would most likely reduce fuel economy slightly. This based upon people trying it and carefully monitoring fuel economy over long periods. They dont really consider overheating to be until in the 240 deg range .
All that said, I'm sticking to my stock stat.

Dew

jethroish

205 is hottest I have seen my 2018. That was pulling 12k horse trailer in 90 temps at freeway speeds.

NC Ram

Running around unloaded. I show engine at 190, trans at 170, oil at 200. At least within a few degrees either way.

Parked and idling on a hot day all temps go up about 10 degrees.

Towing a 5500 lb trailer up mountain passes , I've seen about 10 degrees plus on the engine. Very little change in other fluids.