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Discussion Starter #1
Will a thermostat from a cummins dodge ram work on my 4bta? I ask because my engine is running cold and I was wondering if I could just go to the local parts store and get a hotter thermostat instead of going to a cummins dealer.
 

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cold engine

Mine seems to be running cold too (165 deg. F). I have the stock 180 deg. 4BT thermostat in mine and have been puzzled by how cold it runs. What temperature are you seeing?
 

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it has been my experience that these are just cold natured motors (running temp wise) The first one I ever started was on a 40ish degree night and took nearly 45min idling to reach running temp. In 90 degree heat in stop and go traffic it will stay around the thermostat temp
 

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The Cummins thermostat works differently than a conventional automotive type as it operates within a range of temperatures. It will begin to open slightly at around 165 and will continue to open as temp increases until it is fully open at 190. If the slight amount of coolant passed as the thermostat begins to open is sufficient to decrease coolant temp to below 165, it will close again and the cycle will repeat. Automotive thermostats are more or less open or closed with no in-between. Long story short, if your cooling system has plenty of capacity and you are in a cold climate, 165 is probably as warm as the engine is going to get.
 

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if you aren't towing cut down the cooling capacity by covering a good portion of the radiator with cardbord or something... check out what the big truck drivers do... they have little tarps with a diamond hole in the center that they can adjust the size of.
 

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as you can see i live in mass we haven't had many cold days this year but just recently we have had days in the teens and the 4bta tops out at about 190 as far as my electric fan lets it go...
i'm not sure if i'm in a cold climate but it dose well for these temps.
i am also going to try blocking off half of the radiator for faster heat.
still learning-
racing rex just saw your reply sounds good.....
 

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Discussion Starter #9
Thanks for all your advise, I will be installing a hotter t-stat and gauge this weekend.
Mine seems to be running cold too (165 deg. F). I have the stock 180 deg. 4BT thermostat in mine and have been puzzled by how cold it runs. What temperature are you seeing?
I don't know, I am basing this on the original gauge in the stepvan. ('gasp' yes I actually have a use for the van right now, but later this fall I'm liberating the engine) I realize that the gauge or the sending unit could be off, so this weekend I will be installing a mechanical gauge. I'm guessing that the radiator is the original one for the old 5.7l v8 which would be too big. It has been getting damn cold out here in the desert.
if you aren't towing cut down the cooling capacity by covering a good portion of the radiator with cardboard or something...
I did that on the 400 mile trip home last fall when I noticed that the heater in the van barley put out any heat. I've done that for years in the winter on my diesel car and it works wonders. However I have also noticed that when I drove it down to an area recently where the temp was 80 the engine temp was still low. I am worried about running the engine too cold so I want a hotter t-stat.
 

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i think the cj might be smaller but i did buy the v8 conversion radiator thinking i would need the capacity hmmm....
so your saying a smaller/thinner radiator might heat faster....
 

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Matt, I also am running the 4bta and have trouble getting the engine up to running temp. Use caution going to 195 thermostat. I tried this and it caused my egt to go up quite a bit. If you push it it could cause you to damage your engine. I went back to 180 after 2 weeks and have been working on a learning curve for covering my radiator. Example, 20* around here for a couple days and I had the entire core covered to make enough heat for a comfortable heater. Been running with half covered for 45 days, block heater at night, warm-up times before leaving vary depending on ambient temp. 30s- 15 mins, 50s- 5mins. There must be a better way and I will eventually figure it out, until then use caution.
Carl


1979 F-250 crew cab 4 x 4
4 bta
ZF S-42 5 speed
Borg Warner 1356 x-case
Dana 60 rear
Dana 44 front
3.55 gears
255/85R16 tires (33.5x10.5)
Hydroboost steering and brakes
Custom 40 gal. fuel tank
Much more later
 

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Thermostat information I found was quite vague.

Does anyone have a Cummins part number for the 4BT thermostat? I bought one a few years ago, now slow to open.
 

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Bumping this one up again. I'm in need of a thermostat for my 4bt as well, and a part number would be great. I'm going head to the parts store and get a 1st gen. Dodge thermostat and see if that will fit. The one I got for the 2nd gen (94+) is too big to fit in the housing.

Thanks!
 

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