2005 ram 1500 4x4 5.7 hemi, 55,000 miles

Problem:
my engine was running cold. I figured the t-stat was stuck open

I bought a new thermostat matching existing temp rating 203 degrees. I tested the new stat in a pot of water and sure enough it opened at 203.

I installed the stat this morning added fluid etc and the truck still takes a long time to get up to operational temp (maybe 15 minutes). It fluctuates drops down and comes back up to operating temp. If i give it some gas the temp drops.

Could there be a clog somewhere? If the water pump was bad or there was a clog I would think the truck would run hot and not cold!

I need help!!!!

 

also...

how bad is it running her cold like that. I'd say she runs at 3/4 of operational temperature.

 

Does sound weird. I was gonna guess open 'stat, too. Maybe the fan clutch isn't releasing the water pump shaft? Where does the gauge settle once it's been running?

 

I would say water pump. How old is the antifreeze?

 

antifreeze is original. I added a gallon after the stat change.

If the water pump was bad, it would run hot.

 

clutch on the fan sounds likely..

are you certain you're running cool? could your temperature sensor/sender be telling you lies? they've been known to fail, though it isn't that common.. borrow an infrared temperature sensing gun and give it a shot to see..

also, if it is the clutch fan: sometimes those things get mud and such in them which keeps the spring element from collapsing and releasing the fan.. and they just need a good shot with a water hose..

 

I would do a complete fluid change.

 

yes indeed. I was preparing to do a flush job. the coolant is perfect and obly have 55k

 

Thats gotta be it!!! I didn't even think about that!!!

Tell me more about te clutch fan. How to test it and when should it ingage. I reckon at a certain temp it's supposed to engage.

My operating temp is just a hair below the middle marker on the guage (just touching the middle mark). When she runs cool it gets 3/4 of the way there. Eventually it will get to operating temp.

It's gotta be the dang fan is stuck on - engaged!

 

Just around the middle mark is about right. As for testing, I'm not sure. I suspect that if the engine is cold, you should be able to turn the fan by hand with no effort and once it's warmed up, the fan should be harder (or impossible) to turn by hand.

Originally, the fans were bolted directly to the water pump pulley. Then they went to centrifugal (at some speed, the fan would just release the water pump shaft because around 30 mph or so, the fan wasn't needed). Then they went to thermostatic clutches - once the air through the radiator fell to a particular temperature, the clutch would release the water pump pulley.

For a bit more money that a replacement fan clutch, you can get an e-fan. That will free up some low-end power. I have a Flex-A-Lite Black Magic Extreme 180 and a 180-degree 'stat. I have the fan set to come on at the old "normal" The new normal is around 1/3 on the gauge. When it gets to 1/2, the fan kicks on and pulls it back down. Otherwise, the fan only "windmills" with no drag on the motor or the alternator. It only comes on when I'm crawling along in traffic.