1999 dodge ram 1500 5.2 engine will not get hot enough for thermostat to open. Had 195 only got to 189. Put 180 only gets to 178. New water pump. Flushed and back flushed entire cooling system. And replaced fan clutch. What is going on. Please help!

 

If you're the same poster as on that other forum, I suggested trying the old pump again and see if it helps.

You have a crate engine with a new pump, correct?

And welcome to Dodgeforum

 

Seen a similar post somewhere, The thermostat was not sealed or tight allowing fluid to pass by it.

 

Thanks at this point I'll try anything.

 

How are you measuring the actual temp? Cover the radiator with cardboard to varying degrees, to see if you can get it to open. Also, heat the thermostat in a pot to make sure it works.

 

Using a thermostat lower than that required by stock masks the symptoms.Always stick with a stock thermostat unless you're running a tune and have been directed to use something different.

 

Used Bosch scanner computer and gauge seem to be the same even used infrared thermometer

 

If possibility of air in the system how to purge I've tried everything front of truck on ramps and all. Been a mechanic for 13 years have never had this much trouble.

 

No sir different person completely stock truck

 

More likely, the thermostat isn't closing fully, or, water is able to leak past it to quickly for the engine to ever get up to temp. Use a Stant SuperStat, to make sure it actually has a better than even chance of working right.