743 Too Hot

[uffda]

I installed a 195 degree thermostat in my 743, and the gauge is running hot. I have read that it could be other things causing it to run hot. For now , I just was wondering if this thermostat is ok as installed. If it is, I will start checking other areas that may be causing it to run hot. Can the sending unit and the gauge be checked with the multimeter. Hope its not a head gasket leak..

 

[FJRDarksider]

Not suggesting it's your belt driving the water pump as I think the 743 motor is mounted inline so the belts are visible, but when I bought my old 853 earlier this year, the prior owner said it ran hot so he installed another sensor, but it didn't change anything so he would just run it till it started getting too hot, and shut it down to cool. He also kept it on a battery charger all the time......

I discovered the belt driving the pump (and alternator) had come off (hidden by the guard so not easily seen).......who knows for how long but I threw a new one on and its been running great all year without issue thankfully.

 

[foton]

I think they ran 180 degree F new. and really diesels are more efficent at 195 F as long as your cooling system design and condition it can keep it at that temp. during hard use, you will be ok with the 195.

 

[laurencen]

take a actual temperature reading 195 is high but should work fine, check good airflow over radiator, are both rad hoses getting hot?

 

[Tazza]

Check heat at both ends of the radiator with an IR thermometer. The coolant coming out should be much cooler than what is going in, if it's not a big difference, your radiator fins are plugged, clogged core or your cowling is not right.

 

[oiu789]

Why did you need to replace the stat that was in it? I have bought new ones that that were bad. They had lost their gas charge. Check the eng side temp and then rad side to see if it is the same. Or take it out put in a pan of water on the stove with a thermometer and heat it up to see that it opens around 195.

 

[laurencen]

on the fan housing there is a couple covers, possibly one of the covers have come off which will reduce the air flow to the radiator

 

[uffda]

I changed the thermostat because the old one would not close completely during the test. I got a 195 because that's what NAPA had in that size. I cleaned the radiator and oil cooler fins and it still seems to run hot unless the 743 temp gauge is known for running hot

 

[foton]

use a laser temp gauge aimed at the bottom of the thermostat housing to get a reading,that will let you know . it could easily be a bad sending unit giving that gauge a false reading.

 

[haymaker]

All the above are good suggestions but.
What are you considering "too Hot"? Is the gauge showing it in the red? Does your gauge give an actual temperature?
I don't remember if my 743 showed an actual number range or just a green zone and a red zone.

 

[laurencen]

its not unusual overheating on the 743 is a cracked head, had 2 over the years that overheat because of this,