Thermostat for 1st Gen

[LShute]

I have a 90 Ram. From reading what I could find, I got thermostat 3934373 from Cummins. I noticed it didn't have a jiggle pin and called Cummins to check on this. The person I talked to asked me for my engine number (44449138), then said what he was looking at said the correct thermostat for my engine was 3917324.



Since day one with this truck, the temp gauge registered less than 1/3. I'm now using a thermostat from an autoparts place that causes the temp gauge to register at 1/3. So I'm looking for any info on what to do. I don't know if all the thermostats I've used are bad, if the gauge is off, or my sending unit is off. I've seen a lot of posts regarding thermostats and it seems to be a source of quite a bit of confusion. Should I put in the 3934373, get a 3917324 or keep the cheapo thing I've got? Thanks for any help.

 

[nascar mark]

If your truck is running at 1/3 on the gauge with the after market on and the factory ones like mine/your old one runs just under 1/3, I would leave the after market one in if it cycles fine as our cummins like to run best at 190 deg. Factory thermastats seem to run around 160-165 deg no matter which one you put in.

Warmer is better.

 

[BushWakr - RIP]

I'll add to marks feelings on this one too.

I wasn't really aware of the 'actual' temps until discussing it with him one day. His readings suggested that my rig also was running at less than "optimum" operating temps.

It is preferrable to have a normal operating temp of around 185-195'ish for these trucks. So long as your thermostat cycles properly to keep your high end temps in the safe "upper max range".



bob.

 

[Bob Beauchaine]

Ive got an aftermarket temp guage on my "93 and it swings between 170 and 185 with a Cummins thermostat. That equates to about 1/3 on the factory guage. There have been several revisions and as I understand it the latest will cure the temp swings. BTW my factory installed thermostat did not swing but ran at about 170 consistantly. Hope this helps.

Bob

 

[JLEONARD]

Not sure what the temp on mine is but it runs at about 1/3 the gauge travel. It varies about the thickness of the needle, that's about it... . winter or summer. The heater drives me out of the cab even when the temps are in the single digits (F).

One of these days I'll remember to check it with my temp gun.





Jay

 

[LShute]

Thanks for the feedback. I'll keep what I've got.