M1009 Runs Cold

[Russm]

Recently put in a temp gauge and sensor, replacing the idiot light sensor.
Found that my truck runs cold. Temp never goes above 140*F. Even after extended periods of driving around the city.
Ambient temp is 60-70s so it's not like it's too cold outside. My brother's 1008 runs around 180F.

Is this a problem?

 

[Matt Kahle]

When you bought your truck did the last person, change the water pump?

 

[nyoffroad]

Are you sure it has a thermostat in place? If it's missing that will keep it from warming up, it could be stuck open too.

 

[Matt Kahle]

Um thats where i was going with my question, What i was getting at that maybe who ever replaced the thermostat may have replaced it with one that allows more coolant into the engine (A colder thermostat) Some one may have done that because these engines can get a little hot. I remember reading an article that the army had problems in the desert heat, it caused the engines to over heat and fail.

 

[rsh4364]

I ran into this a few years ago,I would get 18-22 mpg in summer but it would drop to 15-16 mpg in winter.My thermo-stat was stuck open,switched out and winter mpg came back up.Something else my Dad taught me was to test gauge before install.Boil a pan of water and dip probe in,water boils around 212 degrees.Just to make sure gauge is calibrated correctly.I have never come across a bad one yet,but it cant hurt.

 

[Assel]

You can verify if your theromostat is working correctly even without a gauge: Start you CUCV when the engine is cold, then wait ~2 minutes and then put your hand on the big hose on the drivers side, it should be cold or atleast handwarm (depends on outside temp.) then put your hand on the water bridge just in front of the Aircleaner (Attention it can be HOT!). The water bridge should be way hotter than the big hose, the thermostat sits right between those. If both have the same temperature all the time you have a stuck-open thermostat or your just missing it .. when you drive around until the engine is warmed up, both should be hot, almost untouchable ^^

dont blame me if you get a burn !

 

[Russm]

Temp probe is working properly. Gauge shows 140* at most and the hose feels like hot water from the faucet. I can keep my hands on it.

 

[Russm]

Would any of these be the proper thermostat?

 

[Drock]

I'm thinking this is ah gauge issue. Where you put your probe really matters. And I find it hard to believe that ah CUCV runs cold. The best place for your gauge probe on ANY engine is at ,or as close as possible to the thermostat (on the engine side) , or upstream of the stat. This gives you the final temp of the coolant (just) before it leaves the engine and enters the radiator to be cooled, thus it's much more accurate. This is why ah lot of guy's (myself included) swap out the coolant crossover for the HMMWV version. Which has extra bosses cast into it for your probe.

 

[Russm]

Just to clarify. I need the 195* thermostat?

 

[Drock]

Just to clarify. I need the 195* thermostat?

correct

 

[Russm]

Issue seems to be solved. New thermostat is in and it is warming up to the proper temperature now.

 

[rsh4364]

Good deal,you may even see a slight mpg increase.