So much FUD gets parroted around here. I had to reply!


^^^^ This reply above nailed it! Well said. He is correct. Doubt me or him? Take t-stat out and run it. I bet it runs cold and never warms up destroying the theory others posted. I can save you time and say I have done it and I am right. But, don't take my word. Try it!

 

This isn't completely true at least in my situation anyways well the whole part about thermo max mad min temp part that you said cause my max meno was bouncing off 230 with 195 thermo but quit doing that with a 160. Maybe someone can help I know this is a Jeep forumn and I'm new to this so bare with me. But I have a 89 Silverado 350 was told it was a 355 when I bought it. So summer time with oem Thermo it would run 210 no problem never above or under winter time it bounced from 210 to 230 when it's like 40 degrees or colder so I had enough of it replaced the water pump radiator and cap replaced the thermo with oem recommended 195 I also did both coolant sensors and put aftermarket gauge did not solve my problem. So I put a 160 in it and now when it's 40 degrees or colder it runs about 190-200 now it's like 60 degrees outside this time year and it stays right at 210-212 any ideas? Sorry for posting this on a Jeep forumn but I'm just looking for answers. As of right now I'm just driving it cause to me 210-212 is a healthy temperature. But I'm wondering if I have a underlying problem that's under my nose that I don't know about and maybe a 160 thermo is hiding another problem? Oil looks good not leaking coolant of course but I just don't wanna take it to a shop cause I don't know what else they can do that I haven't

 

You should have just made your own thread this is not the place for your question.
What kind of fan does the truck have? If it's a clutch fan, how old is the clutch and is it working?
does it have the fan shroud?
Is the fan set in the shroud properly depth wise?
have you verified the temperatures with an infrared thermometer?