truck gets up to around 190 then just drops randomly then goes back up all within a few seconds...do i need a new thermostat?? ive heard of people putting different ones in???

 

This is normal.

 

What you are experiencing is normal. This scare a lot of people but there is nothing wrong. All you are seeing is the thermostat opening and closing. When it opens, the cold air from the radiator enters and causes the drop. They eventually relocated the sender to decrease the number of complaints about it.

 

Hopefully its water thats entering, not air.

 

I made sure mine was topped off and added a wetting agent you can get from Red Line. It helps smooth out the roller coaster needle.

 

thanx everybody...does it have anything to do with the truck being really cold natured...even on 70 degree days it takes awhile to get goin...ive been told its just the way the 12 valves are

 

It is a really big cooling system and they put the temp sensor way in back. What you see is a slug of cooler water coming through when the thermostat opens. They moved the sensor on later years to stop most of the fluctuation.