What is wrong with all my thermostats?

JKP · Jan 2, 2026

I wouldn't swap it if it's working.

Flowkooler/Robertshaw is supposed to me more stable, but I really can't tell if it's any more stable than a Stant Superstat based on the TJ gauge. You'd have to compare OBDII data since the gauge is somewhat damped.

Advance swapped out my failed Stant Superstat with a Motorad Ultrastat. Doesn't look bad, but doesn't have the jiggle vent.

Moglocker · Jan 2, 2026

JKP said:
I wouldn't swap it if it's working.

Flowkooler/Robertshaw is supposed to me more stable, but I really can't tell if it's any more stable than a Stant Superstat based on the TJ gauge. You'd have to compare OBDII data since the gauge is somewhat damped.

Advance swapped out my failed Stant Superstat with a Motorad Ultrastat. Doesn't look bad, but doesn't have the jiggle vent.

I redid the whole system mopar everything in 2020,been all over the USA ,no problems,if I sit idling in the summer w/ac it will climb passed half way,I think I might do something to raise the rpm to keep the (wench)lol cool when I go into a store or something.

JKP · Jan 2, 2026

Pick up a bluetooth OBD reader to see what your temps actually are.

Mine will approach 220 if it's scorching out, idling with the AC in GA. The gauge just shows a needle width or so above 210. As soon as I start driving, it's 205 to 210. Mopar rad, Robertshaw thermostat, Advance pump.

Edgar Marton · Jan 5, 2026

JKP said:
And in that MOPAR box will be... a MOTORAD.

That's exactly how it is. MOTORAD's thermostats last about six months and then they all break. I've already installed five thermostats, motorad and Gates, and they're all bad.

MikeE024 · Jan 13, 2026

JKP said:
And the current 05, 06 TJ MOPAR cam sensor is junk as well, it is not the same as the original one.

Not sure what you mean by current 05-06 TJ Mopar cam sensor…it’s been discontinued for years.

The4bangertj · 2026-01-22T15:38:20-0700

Well even with the all new Robert Shaw thermostat, water pump, hoses, radiator, coolant, and trying to bleed the system many times I’m still stuck at 170 again. I’m getting so tired of the replacement parts available for this jeep.

JKP · 2026-01-22T15:44:05-0700

You may have a bad temp sending unit. I don't remember if you replaced it.

The4bangertj · 2026-01-22T15:45:51-0700

JKP said:
You may have a bad temp sending unit. I don't remember if you replaced it.

I thought so too but that’s only a year old and both the coolant lines and heater core are just not hot.

KennethS · 2026-01-22T18:36:48-0700

I’ll sell you my verified working properly for 5 years thermostat for $50.

The4bangertj · 2026-01-22T18:40:32-0700

KennethS said:
I’ll sell you my verified working properly for 5 years thermostat for $50.

lol you’d be surprised how tempting that is. Thankfully flow koolers is sending me out another thermostat.

CMBD · 2026-01-22T21:17:00-0700

I like to test stuff once in a while cuz ya can...

You ever test any of the thermostats you have replaced? Take actual temps not via OBD2?

I dont always, but I tested the last thermostat I pulled and the replacement before I put it in. Because you dont know what you dont know

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What is wrong with all my thermostats?

JKP

TJ Addict

Moglocker

TJ Expert

JKP

TJ Addict

Edgar Marton

TJ Enthusiast

MikeE024

TJ Expert

The4bangertj

Aluminum diet

JKP

TJ Addict

The4bangertj

Aluminum diet

KennethS

TJ Addict

The4bangertj

Aluminum diet

CMBD

Button pusher.

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