ofelas

Esteemed fellow members, two of my friends & I were chatting about 12v coolant temperatures yesterday afternoon.

boeingguy observed that his ’93 with OEM Cummins stat never got above 150f during a 600 mile run yesterday.

G1625S mentioned that was about optimal for an unloaded 12v, and that his JD lawn pig with coolant unchanged from 1988 ran similar.

Furthermore, he mentioned that my old 12v truck running at 180f+ (verified at multiple points on top rad hose, stat housing, heater inlet hose etc) in winter was an anomaly.

I pondered this for a while, as I believe in monthly coolant changes with Genuine Mopar MS9769.

Well, 1988 coolant is fine, at least it’s OEM JD fluid. Who needs corrosion inhibitors after the first 3 years, totally over rated.

If Mopar made a tractor, now that would be awesome. Anyway, I digress.

It suddenly struck me that my truck may run optimal as I use OEM NOS Genuine Mopar thermostats. After all, Genuine Mopar made Cummins great again way back in 1989 - this term was actually patented by Mopar when they sent a winged chariot to Randleman "Mopar made NASCAR great again"

Perhaps boeingguy’s OEM Cummins brand stat was the problem?

I humbly submit my verified findings -

Observe Genuine Mopar stat part # 05014568AA - ignore the cheap Cummins box, its been superseded by the Genuine Mopar parts label.



Observe boeingguy’s issue - stat’s supposed to be closed at 150f - but he has a warm top rad hose - so stat is stuck open, leading to NABGM (Not Approved By Genuine Mopar) unloaded temps.



Observe Genuine Mopar stat cracking open at 182f (Cummins spec is start opening at 181f, Mopar correctly delays by 1 degree to check Genuine Mopar MS9769 silicate content).

Observe Milwaukee verified laser heat gun (secretly made by SnapOn for Mopar Aircraft Club).



Observe Genuine Mopar stat fully open at 205f (Cummins spec is 203f), Mopar correctly keeps open 2f longer to check Genuine Mopar outer seal # 04761291 (Cummins seals usually give up a few degrees lower).

Also observe SnapOn pliers to not mar the edge of my Genuine Mopar stat -



Observe thermostat opening at approved width, verified by Forster calipers - this Genuine Mopar width spec is what makes my old truck run at a perfect 182f in winter.
I scrambled the dial to keep this width secret, Cummins can keep guessing.



All parts & tools wiped clean by T9 BoeShield.

boeingguy - you have an incoming package incoming, via Rubi Mata (100% Genuine Mopar, she was named after the Mopar Rubicon).

edwinsmith

I have a 190 deg. stat in mine. I had a gutted stat when I got it which is why it had almost no heat. A lower temp stat makes you burn more fuel.

boeingguy

and low cabin heat to boot, as usual ofelas is on point and goes the extra mile.

1STGENFARMBOY

I just put one from Geno's garage in my truck a few months ago, I had no heat unless I blocked off the front of my truck, I finally replaced the t-stat and have wonderfull heat now, it goes up to just above middle of the guage in 4 miles @ 30* and then drops down to 1 line then slowly climbs back up to just below middle in 8 miles of 60mph driving.


Dar