Should I replace the thermostat?

[curtjames37]

Hello all, been a while since I have posted. I recently bought a new to me truck. The truck is a 2007 Dodge Ram 1500 with the 5.7L. I have noticed the temp gauge will run a little cool when the temp outside is cooler (70ish). I am suspecting that the previous owner may have replaced the thermostat with a 180* unit. The stock temp on the hemi is 203* according to the NAPA website. The truck has 42k miles on it and as far as I know is running on the factory fill coolant. I would probably go ahead and do a drain and refill if I decide to do the t-stat.

With all of that being said, would you replace the t-stat? It may just be an inaccurate temp gauge for all I know. But with the cooler months approaching, if it is the wrong thermostat, I would like to correct it. What do you all think?

 

[Chris142]

Buy one from the stealer if you do replace it.

 

[FusilliJerry82]

I personally wouldn't bother unless you're having any drivability or heat problems. Are there any other things that might make you think the thermostat was replaced like knowledge it was used for towing or any cooling accessories installed like an ATF cooler?

 

[oilboy123]

If you do take it out it might say the temp rating. Otherwise might not make any difference when replaced with another one.

 

[curtjames37]

Originally Posted By: FusilliJerry82
I personally wouldn't bother unless you're having any drivability or heat problems. Are there any other things that might make you think the thermostat was replaced like knowledge it was used for towing or any cooling accessories installed like an ATF cooler?


No drivablility problems and its still too hot here to be worried about heater performance. It does have an ATF cooler but it came from the factory with the tow package so I believe that to be stock.

I work second shift so I often drive home at 2-3 AM when it is cooler outside. The temp gauge is noticably lower at this time than it is when I go to work in the afternoon. The gauge will show about 3/8 in the cooler temps.

It may very well be just an inaccurate gauge. I know it bugs me though.

 

[curtjames37]

Originally Posted By: oilboy123
If you do take it out it might say the temp rating. Otherwise might not make any difference when replaced with another one.


You are right I remember the thermostats on my old truck always said the temp rating on them. Maybe I will try to take it out without losing too much coolant to have a look.

 

[JimPghPA]

Make sure you have new gasket and sealant. You can not reuse old gasket.

 

[Cyprs]

How big is the rad? I have a 1986 Toyota, it has a rad half the size as my 1987 Nissan, both have exactly same 2400cc sized engine, both cast blocks and aluminum heads.

The Nissan temp gauage will never show proper heat range when cool in fall temps above freezing and even after 40 miles highway driving in -30F, My father's 1985 Honda Civic was exactly the same way from day he bought it new.

The small rad Toyota is a dream in fast efficient warm up in my cold temps the engine will warm up when extremely cold.

Cyprs

 

[Cyprs]

I have a 92 Dodge Cummins Truck, big Radiator. On a cool +40F day like today I use a heat pad on oil sump and block heater for an hour on timer. I live near #1 Trans Canada Highway. I idle about 3-5 minutes and drive off gently to about 35 mph in third gear (no overdrive) with no lug on motor, auto tranny. It will take me 5 minutes of 35 mph driving down the highway on large road shoulder before that engine is ready for a moderate load, the temp gauge is getting close to safe operating temp, even at that point my engine oil temp is in the below 160 degree high wear metal zone so I moderately load the engine faster. In -45F weather it takes more heat pad, block heating and idle time and 15 minute patient drive off before a moderate load on engine to keep my iron ppm down to about 5 ppm iron wear on UOA.

Patience is probably our best friend on slow warming engines or any engines I drive in my experinece. I Leave for destination earlier works for me. I get long life out of all drivetrains this way in my extreme weather and immediate highway drive off.

Cyprs

 

[M1Accord]

It would be nice if temperature gauge has an indicator of what is considered normal instead of hot and cold range. My 92 Corolla temp is always at the mid level after warm up while my 02 Accord is always at the 1.5/5 mark.

I changed my thermostat out when I did my 100k service even though I didn't need to. I keep the old part just like I keep the TB, WB, and other parts that could have gone another 30k miles in case I break down some where and they can't find the part to it, I can just give the mechanic these parts and they can do the work. OEM Honda TB looks new after 100k miles and the same for the drive and steering belts. These belts are Made in USA just like much of the car. I may just get another V6 Accord of the same era since this car has been a dream to own.

Does anyone know if I4 Accord and V6 Accord use the same belts and water pump? I don't see why they use use different stuffs. That would help since I prefer I4 Accord over the V6 for better gas mileage while having the same size gas tank. The newer Accord has 18.5 gallon tank so if it gets 32 mpg, I can do some serious road trip and be safer when picking places to pump gas. Under extreme circumstance, I can go 544 miles and wouldn't have to worry about killing the fuel pump because there is still a 1.5 gallon in it. I can knock a VA to FL trip in 1 fill up half way in Georgia where gas is significantly cheaper than NC or SC.

 

[curtjames37]

Well, curiosity got the best of me. I pulled the old thermostat out to see if it had any indication of the temp rating on it. Sure enough, it was a 180* t-stat. Replaced it with a new thermostat and gasket from the dealer and topped it off with Zerex G-05. We will see if it makes a difference in the reading on the gauge.

Thanks everyone for the help!

 

[mechtech2]

curt - You did a very good thing.
Cruising gas efficiency just went up [heat is not being lost to constantly try and bring the head and cyl walls up to homostasis].
Winter heat will be mush better.
Any condensation in the crankcase will be minimized.

Remember, when you need it, an open thermostat is open!

 

[oilboy123]

Yep, used to be everyone thought cooler was better but if it's stock better to be at the 195 degree range. Especially in the colder areas, or Winter.

 

[Spykem4e]

I had a 300c with the 5.7L engine in it and I could see the temp needle being lower than usual after 30k miles on the car.

I checked the thermostat and all that was made of rubber was falling in pieces so I replaced it with an OEM one and never had a problem with temp after that.

Very easy to replace if you don't know: on the hemi engine, it is suppose to be right in front of you when you stand in front of the engine. You'll see the upper hose from the rad. The t-stat is right there, on the engine.

Update: - LOL I didn't read all the posts and never saw that you did changed the t-stat. Hope everything works out!