so drivin down i25 @75mph with ac blowin cold outside temp 99F. temp gauge showed a bit higher than ive ever seen about 210. no problems, coolant is good never had a problem with overheating or over cooling till now. i wasnt hauling anything either.

Now the issue i think is the tstat is stuck open allowing over cooling. barely will hit 170 in 99f heat with ac runnin doing 65.

the fan is working fine, blowing strong but not locked.

so i am gonna order a new 195f tstat and bolts then swap this week.

thoughts?

I think you got it. I took my thermostat out to see what would happen once and it was on a hot summer day and I barely got to 140 after 10 miles.. The thermostat even wide open still creates a restriction so its better than what I did with no thermostat at all. The water flows so fast it just cools it way too good. Sounds like a good thing but a cold engine is not an efficient engine.

  ISX said:

I think you got it. I took my thermostat out to see what would happen once and it was on a hot summer day and I barely got to 140 after 10 miles.. The thermostat even wide open still creates a restriction so its better than what I did with no thermostat at all. The water flows so fast it just cools it way too good. Sounds like a good thing but a cold engine is not an efficient engine.

yup ill order oem stuff monday and fix it this week

Ill be watching this one since my dash gauge has bee reading low for a long time. Hope the tstat fixes yours. the mechanical gauge I installed completely disagrees with the dash gauge in mine.

Yea... I would say start with the thermostat. I would just get a NAPA thermostat first.

  Mopar1973Man said:

Yea... I would say start with the thermostat. I would just get a NAPA thermostat first.

yeah ill do that and get bolts in case one snaps from corrosion

  CUMMINSDIESELPWR said:

yeah ill do that and get bolts in case one snaps from corrosion

... Use anti-seize and that problem won't happen and they are just small little 8mm head bolts so they shouldn't be very tight at all.

  Mopar1973Man said:

... Use anti-seize and that problem won't happen and they are just small little 8mm head bolts so they shouldn't be very tight at all.

18ft-lb per manual but i will tighten enough to seal. good point on antiseize. i picked up a 190 from advance, napa didnt have one...

ok so i have a resolution to my issue.i drained the radiator to not lose anything and popped the housing off.this is what i found.[ATTACH]5932[/ATTACH]and i pulled the tstat out and inspected it and found this[ATTACH]5933[/ATTACH][ATTACH]5934[/ATTACH][ATTACH]5935[/ATTACH]this tstat was original at 196,500 miles and the rubber seals had degraded and disintegrated allowing coolant to flow at any time thus rendering the engine cold. it had also locked closed so i was lucky.good news is i have no scaling in the block and its clean as a whistle.[ATTACH]5936[/ATTACH]after install of new 190 tstat i blocked radiator and worked air out of system and it hit 190 on the gauge quick and it opened up and the top hose got nice and hot. work good last long time!ill give a update in a week to inform if all is still good.

initial driving/sitting heat load test is stable at appx 185-190[ATTACH]5937[/ATTACH]

i had similar troubles almost 2 yrs back. it would take 20-30 miles of driving with only work gear loaded to blow warm air thru the vents in tulsa winter(avg. 20-40*f). it would hardly reach 190 even when towing for hrs. after changing the thermostat to a 190*F auto-part store replacement i noticed a big change. warmed up within 10-15 miles. i noticed that it doesn't open the 1st time until about 205*F but after that opens at 195 and closes at 185. i flushed the coolant a few months back and the results were the same after the flush. last week i re-installed the fan/clutch because i noticed idling at long lights that the temps would climb above 215 before i started moving again.i will admit it was a little unnerving to watch my temps hit 205*f the first time after i changed the thermostat after 2yrs of barely seeing 170:ashamed:

60 mile drive to work and temps are normal.