Engine/Transmission (1994 - 1998) Which Temp Thermostat To Use?

[RHestand]

My OE temp. gauge reads 170 to 175 degrees operating temp. in either hot or cold weather.

In cold weather (-5 to 10 degrees) I have to keep my heater going full blast just to stay warm in the cab.

As soon as weather started cooling down,I made and inst. a cardboard rad. shield ( with a 6" hole in the middle) between the IC and the radiator, but I think the coolant is still just not getting hot enough.

Wouldn't it be more efficient and better for the 12V to be at 190-195 degrees?

That's what my 06 runs at.

What temp. thermostat do guys run?

I know the OE gauges are not very accurate, but I'm thinking about buying and inst. a 195 stat and see what that does to my temp gauge and my interior heat.

What do you guys think?

Thanks, Ray

 

[Shadrach]

Cummins doesn't make a 195 stat for your 12v. They do make a "slow cycling" stat for that gen of engine. It opens slower and doesn't allow the gauge to "swing" like the std stat does. Your 06 has a 190 in it.
Shadrach

 

[Skydiver]

Check the flow rate on your heater core. It could be restricted. After the engine is up to operating temp the core outlet hose should be almost as hot as the inlet hose. Be careful not to burst it if you use a garden hose for flushing. An all day job to replace it. If you are seeing 170 on the guage the heater air flow should feel very warm at the source.

 

[Dr.Bob]

Shoot your engine to see what temp it's running, it might be your gage. If not you might have a stat stuck open. I went back to the swinging stat at least I know it's getting to 190 even tho it does not stay there.

 

[hsmith]

Me too, don't mind the "swinging" gauge.

 

[ata]

Cummins doesn't make a 195 stat for your 12v. They do make a "slow cycling" stat for that gen of engine. It opens slower and doesn't allow the gauge to "swing" like the std stat does. Your 06 has a 190 in it.

Shadrach, Do you have a part number for that thermostat. My engine stated running at 170 so I went to Cummin's and got the only stat they said they had for a 12 valve. Well YOYO temp gauge. So I went to Dodge and got the only one they had listed for a 12 valve and still YOYO time. Both Dodge and Cummin's said the stats are the same just different part numbers. The boxes are the same except the Dodge box has a small MOPAR lable on it. This 185 to 165 to 185 every 2 min's on the road really bugs me.

 

[DPashko]

you can also use a Dodge 440 tstat i think they come in a 190 and 210.

 

[Dr.Bob]

I used the slow cycling stat and my temps stayed at 165 so I prefer the yoyo.

 

[RHestand]

My temp. gauge does not swing. After reaching operating temp. it stays there. Maybe mine has the slow cycling stat. inst. already?

I havn't driven my 98 since I started this thread, but when I do, I've got several things to check into now. Thanks for all the info. guys.

If DPashko is right, which would be the better choice? Is 210 too hot?

Thanks again, Ray

PS: I have not driven my 98 because I'm trying to install new front shocks.

After working on them for a very cold, frustrating, 5-6 hrs. yesterday, I finally got the rusty and rounded off bottom bolts out. After lots of heat, smoke and JB Blaster, I got them broken loose. Now I need new bolts.

Is there no such thing as a 20MM socket? My 2 metric socket sets go from 19MM to 21MM (19 too small/ 21 too big), so I tried to buy one, not to be found. I got it done by beating on,and ruining, a too small 13/16th-six point socket. I hate rust!

Sorry for the long post. I just had to "vent".

 

[Ted Jannetty]

The hotter the better, I found a 175 stat from Napa that helped with the heat on my 97.

 

[DPashko]

I double checked the thermostat temps for a dodge 440 and i was a bit off they come in 3 different temps. 160, 180, and 195. mopar has quit carrying them but napa has them. I forgot i had one in a 97 years ago that a mechanic putin for me and it ran nice and warm as long as your not sitting idling all day. I went and grabbed a 195 today and Im going to try it out again seeing how my t-stat is currently stuck open.

 

[Ted Jannetty]

I double checked the thermostat temps for a dodge 440 and i was a bit off they come in 3 different temps. 160, 180, and 195. mopar has quit carrying them but napa has them. I forgot i had one in a 97 years ago that a mechanic putin for me and it ran nice and warm as long as your not sitting idling all day. I went and grabbed a 195 today and Im going to try it out again seeing how my t-stat is currently stuck open.

I don't think a T-Stat from a 440 is interchangeable with a Cummins, if it is that would be real Cool or HOT

 

[RALLER]

Swinging thermostat

Drill a 1/8 hole in the thermostat. This alows just enough warm flow by the wax pellet to stop the cycling. this works great in a warm climent. I live in Las Vegas, so i dont know if 1/8 would be to much flow in a cold climent. I havent tried a 1/16 hole. I am retired now ( this is the way to go if you can live long enough ) But i bent wrenches for 34 years and owned my shop for 23 years. So i have driled a lot of thermostats.

 

[Shadrach]

A "440" stat will fit but won't work properly as it has no flapper on the bottom of it to close off the bypass passage in the block. If you live in a cold climate drilling a small hole in your stat will make it run cold, believe me I tried it on an old Dodge V8 and nearly froze in the cab. Putting a good winter front over the rad ( like Dodge makes for the 3rd gens ) will help keep heat in. Shadrach

 

[WestTN]

Constantly changing temperature increases engine wear.

 

[DPashko]

Have a Dodge 440 Tstat in there now and works fine. temp swing is from 195 down to 192 and heat in cab is fine. Except for when your idling all day long cools off below 120 but no different from the cummins one. But im in -40*C climates! Heats up fast when you start moving again.

 

[Shadrach]

I guess real life beats theory hands down Shadrach

 

[MMcCallie]

I've been thinking about this the past few days and it doesn't make sense to me. I have a 180 thermostat that swings like most. Thing is, I don't get any heat whatsoever in the cab until the engine coolant temperature has reached 180 degrees. The thermostat is shut until it reaches 180, so even if the engine is relatively warm like say, 160, I won't get any of that heat in the cab until the engine reaches 180.

It takes a very long time for my truck to reach 180 in cold weather. But once it gets there the heat doesn't fade as long as the engine is still running. In fact, I've seen the gauge in my vent show 150 while driving on I-80 while it was in the teens outside. Gets plenty hot in the cab but takes a long time to get warm at all. I'm told the 7,000' elevation, constant winds, and extremely dry air contribute to the zapping of all heat from vehicles in Wyoming.

I suppose a thermostat that doesn't open until the engine reaches a higher temperature will allow hotter heat in the cab, but 150 was seriously roasting for me. Isn't the drawback that the hotter thermostat will take that much longer to open and deliver heat into the cab? So wouldn't it make sense to have a lower thermostat like a 160 in the winter so the heat comes in sooner? I imagine that drilling the thermostat would allow some heat into the cab, but take that much longer for the block to warm and therefore feel significant warmth in the cab.

 

[RHestand]

Shadrach,

I bought a 440, 195 stat from Napa, and looked at the Cummins 175.

I saw what you're talking about re: the flapper.

My question is, what is the function of the bypass passage?

I would really like to try a 195.

TIA, Ray