Engine/Transmission (1994 - 1998) thermastat!

[edgeman]

Just before I deployed I was getting a pressurized coolant overflow bottle. I tested the system and found that there was no problems with the head gasket or anything else but the thermostat. After I replaced it, which I went from a 190 to a 180 cause cummins doesn't supply a 190 anymore, but anyways my temp. gauge swings back and forth from 140 to 190 like a windmill... . is this a problem or should I just leave this alone..... ?

 

[DennisDuncan]

That action is something that seems to be a trademark about the cummins. A factory thermostat helps it the most, but it never really cures it... I don't like it myself and I have 5 of them, and they all do it.

 

[CNolen]

I have the same problem, but you say a factory thermostat helps the most. By factory do you mean Mopar or Cummins?

 

[edgeman]

Cummins..... go to cummins for your factory thermostat.....

 

[Shadrach]

To prevent the thermostat from cycling too much use Cummins stat p/n 3934373. It is a slow opening stat and therefore won't cause the swinging that you are talking about . You will also need 1 of each rubber p/n 3925466 & 3927305. This stat fits 94-98 only. Shadrach
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