Better Fan Clutch

I am having trouble with getting my new '98 5.7 up past 160 degrees. I feel that the guage is correct and the coolent in the bottle never gets above half way between the lines, and it does the same thing when I put the old thermo in. Along with the new radiator is also a new fan clutch which I don't feel really let's go all the way. I say this because with the stock one that came off I never had the "fan roar" last so long when cold, plus I never heard the fan at all after it broke loose. With this new one I can hear the fan when I accelerate hard.

If the clutch is turning that fan more than "normal", will that keep my engine from warming up completely?

No, the fan just cools the coolant in the radiator. Driving down the road flows much more air through the radiator and the coolant temp doesn't drop then. If the thermostat is functioning correctly, the temp should still get up to whatever the thermostat is.

Confirm the gauge is correct, I feel the gauge is wrong, so lets get a tie-breaker :). Easiest way is with a scan tool, check the ECT reading. Otherwise an infrared thermometer works good too. The level in the bottle doesn't usually go all the way to the "hot" line. It's probably a rough estimate anyway, but keep in mind only about half the system is hot (engine), the other half is cool/warm (radiator).

So it sounds like you have two thermostats and they both let it get to 160 degrees? most have the temperature stamped in the bottom of them, see if yours does. I believe you want a 195 degree thermostat in your truck.

I am having trouble with getting my new '98 5.7 up past 160 degrees. I feel that the guage is correct and the coolent in the bottle never gets above half way between the lines, and it does the same thing when I put the old thermo in. Along with the new radiator is also a new fan clutch which I don't feel really let's go all the way. I say this because with the stock one that came off I never had the "fan roar" last so long when cold, plus I never heard the fan at all after it broke loose. With this new one I can hear the fan when I accelerate hard.

If the clutch is turning that fan more than "normal", will that keep my engine from warming up completely?

the thermostat is the problem...you should be at 190 deg f.
cheap thermostats are a common problem in that they will not close..stick slightly open..

a new fan clutch will stay on longer than an old one..after a few minutes it should stop howling,... if not return for another...

I have found that the heavy duty fan clutches do howl longer in cold weather ..did you get the heavy duty clutch ?

the thermostat is the problem...you should be at 190 deg f.
cheap thermostats are a common problem in that they will not close..stick slightly open..

a new fan clutch will stay on longer than an old one..after a few minutes it should stop howling,... if not return for another...

I have found that the heavy duty fan clutches do howl longer in cold weather ..did you get the heavy duty clutch ?

This is the third 190 deg thermo and this one is an upper end Stant, not a Murry as the previous two. It is a Heavy Duty fan clutch as it seems to be that's all that is carried around here. You have A/C this is what you get. I guess I will keep working toward getting and accurate read on the Temp. Thanks.

This is the third 190 deg thermo and this one is an upper end Stant, not a Murry as the previous two. It is a Heavy Duty fan clutch as it seems to be that's all that is carried around here. You have A/C this is what you get. I guess I will keep working toward getting and accurate read on the Temp. Thanks.

I don't like messing with thermostats...in and out ...

since this is something I had happen to me a long time ago NOW I place the thermostat in boiling water with wire attached and dunk a few times to see that it opens and closes properly ...then with the water at the rated temp dunk to see how it opens...do that with the other 2 thermostats...the other possiblity is the thermostat is getting bypassed some how...wrong size dia/gasket defective incorrect etc...

You mentioned that you believe that the gauge is accurate. Prehaps the temp sending unit is corrupt. With a new radiator air pockets could possibly be in your system. Before I put an electric proform fan on my '97 silverado I ran the truck without a clutch fan all winter and part of the summer with a 180 thermostat-kept a sharp eye on the temp gauge. On a straight commute it would never get close to over heating.