The 1st Gen trucks used a “jiggle pin” style thermostat. As our trucks age, these thermostats start to give up and the trucks start to overheat.
Unfortunately, most people replace these OE thermostats with aftermarket ones. Most aftermarket thermostats sell for about $10-25 depending on the brand. The issue is, many of these do not have the jiggle pins that are required for pressure relief pre opening, and also don’t open consistently as there are cheap springs used internally. These aftermarket ones tend to make the coolant temp wander up and down vs keeping the temperature of the coolant stable.
We HIGHLY recommend you run a genuine Cummins/Mopar thermostat (both brands are the same part) as they are the only thermostats we have found, to be consistent in maintaining coolant temps. This is why you don’t see any of the aftermarket thermostats on our site. In all of our testing, we have found them not to work. We have always said we will not sell something we wouldn’t put on our own trucks.
The old saying of you get what you pay for is very applicable to these and not worth the risk of overheating your engine for a few dollars.
Comes with a 180F thermostat and a new sealing gasket.
PN 5292738/3923331 and will only fit the 1989-1993 engines!
