This summer gonna do a coolant change (its only been 7 years possibly) and thinking of changing my thermostat as well as its feeling pretty slow, i can see it go 2-3 needle widths past the middle mark up a hill before it opens and feels like it hangs open to as in 30 degrees at idle it was only 1/4th on the gauge.

What is the temperature of the thermostat? Is it 203F from the factory or 190F. Can't find any good information.

Should I change the thermostat housing to? This is a replaced engine only 7 years old with 40-50 thousand miles on it at worst. Is it worth changing or don't bother. I'm of the party of if you're in there you might as well do what you can but some cars that isn't true.

 

I've always thought it was 190F on the thermostat. I would definitely replace the thermostat housing since you'll be taking the old one off anyways.

 

Surprised its so low for a modern truck. I forgot to mention that this was a California truck, I'm not sure if they did higher thermostats there.
Edit: I just remembered I have the 06 manual. It's 195F according to this.

"The 3.7L/4.7L/5.7L engines use a pellet-type thermostat
that controls the operating temperature of the
engine by controlling the amount of coolant flow to the
radiator. The 8.3L engine uses a movable sleeve type
thermostat. On all engines the thermostat is closed
below 195°F (90°C). Above this temperature, coolant
is allowed to flow to the radiator. This provides quick
engine warm up and overall temperature control.
Coolant leakage into the pellet container will cause the
thermostat to fail in the open position. Thermostats
very rarely stick. Do not attempt to free a thermostat
with a prying device."

 

I put a 180 in my 4.7 years ago from summit. That was the best thing I have done. Runs cooler and seems to give it a bit more pep( might be just me thinking that). Couldn’t be happier with it

 

Doesnt that possibly mess with the ECU tuning due to air temps and etc? I know some people said cooler temps only really works with a tuner due to them richening it more and the hotter temps can cause some leaning out issues. I'm more concerned about MPG as well. I get 8-10mpg when im rushing to the fire station so if i can boost that by even 1mpg im happy.

 

OEM is 203°F

 

Well it aint going to happen my friend. Putting a 180 stat in my truck made it run horrible. It started running rich, gas milage dropped and fouled out my plugs. It has got to reach a certain temp operate correctly.

 

it is? the 06 manual said its 195, well opens 195. I'm an 07 so surely it wouldn't of changed much or do the 203's open early.

 

Well. After some research, here's where things get interesting. P/n for your specific OEM 'stat is 52028898AE. In the factory parts book it says:


However EVERY online search listing for that part number that I have found comes back with 203°. I still have the stock 'stat in my 2003 (same p/n). I have an actual temp gauge hooked up and in the summer it's usually between 199° and 205° depending on ambient temp and speed (I have a hood scoop so that tends to aid in cooling). Towing (especially when it's hot) I generally see it even higher than that (depending on weight).
I realize that probably doesn't help at all, just the information I have to share.