As some may know I changed the fan clutch when my 5.0 was running hot at idle. I also changed the thermostat about 3 months ago. After changing the thermostat my temps dropped from "M" in NORMAL to "N". Now with the new fan clutch the needle gets close to but doesn't touch "N". We have had some 90+ days here AND I pulled a boat for about an hour without the needle touching "N". Close, but not touching it. After driving my truck for 6 years with the needle on "M" I'm having a hard time with the change. Is this normal?

On a good note, my A/C runs without fail. Not a single fluctuation! Coooooold!

 

My needle stays on the N or in between the N and O in any conditions.

 

Mine is usually in between the N and O but lately it's been getting up to the A with the AC on. I think I'm in need of a new fan clutch myself.

 

Mine never touched the N, unless it was overheating.

 

Did you put in the spec'd thermostat? If you are running a colder one, the truck might not run like you are used to. I tried a 160, 180, and now am back to the 195 my 4.9 is spec'd for. I also replaced my fan clutch along with the radiator and water pump when things went bad. The gauge used to fluctuate a bit but never went above "R". Not until I bought a flush kit and really flushed my truck did it level out a "O". Just see how's it driving. If it runs well, it's fine. If it doesn't, try flushing.

 

I'd say it's normal. Cooling system is acting like it did when truck was newer. Your old fan clutch was probably always free wheeling. The new working clutch will always be spinning at 20 to 30 % of engine rpm. As it engages the rate can slowly go up to a max of 80 to 90%. A decent clutch can make a night and day cooling difference.

 

The truck runs great so I will just accept this as the new norm. Thanks for laying my worries to rest.

 

As long as your truck warms up enough to exit closed loop, then I see no problems. When my t-stat was stuck open the needle would barely rise up at all

 

If the top hose is hot the loop is open right?

 

If the top radiator hose is hot then the thermostat is open. Closed loop is like the "cold start mode" I guess you could say. More gas is used until the engine is up to operating temp then the fuel/air ratios are adjusted accordingly. This is how I understand it anyways.