1994 jeep Cherokee 4.0 auto.
Cooling system is new I checked for air in the system and tried to burp it changed the thermostat 3 time and still wont get up operating temp. It doesn't get much past the 1/4 mark on the gauge. I'm not loosing any antifreeze and the system is full. 195 degree stat. Heater control valve is working. Its cold here, but out side temp shouldn't effect the motor temp if everything is working as it should.

 

There are TONS of threads on here about this type of problem.

First thing you need to do is verify your coolant temperature with a thermometer (the IR kind work well). The factory gauges are known to be finicky and unreliable

 

Yep I tried to search. Didn't really come up with anything. I pretty sure its not my gauge because my heat is about half of what it use to be. My heat used to roast you out of there.

 

R u drilling a "bleed" hole(s) in the new stats? R u using "fail safe" stats?

 

If the coolant temperature truly is low (measured by thermometer) then you probably have a malfunctioning thermostat. Failsafe thermostats are notorious for problem. Could also be a failed thermostat that has failed open. Try a new one. Some people like Stant. I use dealer thermostats myself - jiggle pin goes on the top.

 

I didn't drill a bleed hole. But I do think its a fail safe stat. I will see if I can get a new stat from the dealer and give that a try.

 

"Fail Safe" should be called "Fails For Sure" because they do.

 

I don't have a temp gauge, but 1/4 up the gauge sounds about right for a warm engine at idle in cold weather.

 

IR temp gauges are cheap any more and a tool most should have in there tool box because of its many uses. I would suggest that you buy one and start checking things with it so you know where to start with a fix for your problem.

Not for you but I run washers in my race cars/HP street cars that have a place for a T-stat they come in all different sizes, made of aluminum and can be bought in sets to control heat in the block.

 

If you do get an IR sensor to check the temp make sure whatever you're checking is a matte finish, preferably black. And you need to be a certain distance away (usually 4-6 inches or something like that).

 

Went and picked up a IR temp gun. Temp at stat 177 temp at sending unite 175. That pretty close to what my gauge is reading. I order a stat from the dealer ship should be in before lunch tomorrow.

 

177 is close to the temperature the thermostat should start to open at. What are you going off of for the "operating temperature?"

 

I'm going off my factory temp gauge. Before all this my temp gauge would stay at 210 or just under no matter what the out side temp was. It all started during deer season drove 3hr up north temp ran at 210 all 3hrs. Then on the way home the gauge was only ready just above the 1/4 mark. I guess that would be right around 170 to 175. And the heat wasn't as hot as it normally is.

 

The 1/4 mark on the gauge is mathematically 155*....I would think a properly functioning 195 stat wouldn't allow 155* actual coolant temp. Wouldn't think a 195 stat would allow 175* actual coolant temp either.

 

Ill have a oem stat in the morning. I pretty sure at this point its the stat.