1989 2.9 Bronco II coolant temperature gauge won't go to the middle of "Normal" - it stop on "N" and drop lower. Thermostat, sensor and gauge work properly. Coolant is new and good. What can I do with it...

 

Ever since the T-stat on my 87 Ranger stuck shut at 5K miles i've been using a 180 degree Toyota T-stat & the gauge runs right in the middle. Try this, remove the wire from the sending unit shove a nail in it & ground it to the engine beside the sensor. If the temp gauge goes to full hot, it's working as it should & i'd replace the sending unit.

 

My '90 BII is the same, but I hear it's pretty common for them to run like that. My temp needle is usually only rises up to the "N" in "Normal". I've occasionally seen it reach the "O."

Today, I replaced the 195F t-stat with a new one, flushed the system, & installed a new fan clutch (mine was dead)...& the truck is running about the same.

 

The gauge in my 89 2.9 does pretty much the same thing,,
hardly reaches the N, and thats with a motor rad fail safe
180 degree thermostat.
guess it's a pretty common condition.

 

By the Summer - it's safe, but while winter we have -25C (and lower) - it's cold inside the car...

 

Is the thermostat functioning properly? The really true way of telling the exact temp is a live gauge and make sure your thermostat is working at the setting it is. I have used both and found the N is about normal only problem with this is it maybe running to cold after the thermostat opens it should get up to I would say 180 - 190 for the rest of the emissions to work properly. After I did all my mods and ghanged the thermostat to a 180 I found I couldn't keep it above 160 on average and this made the truck want more fuel so it ran rich as you know all these things (coolant temp, O2 sensor, air temp etc ) all are related somehow in the computer, each one of these things effect something else in the computer. I believe the stock thermostat on these are 190 correct me if I'm wrong. You can make all the changes in the world to that computer controlled engine but remember changing 1 thing will make the computer compensate somewhere else whether it's the O2 sensor, TPS, poor milage. You need to make the changes you want and then reprogram that computer with a chip that is specific to your changes otherwise you could be just causing greif on other parts.

Best solution is ditch the 2.9L and shoehorn a 302 carb and make the adjustments you want. I did all the 2.9L mods out there excluding the chip and they worked but I feel not to the max. I have now pulled that 2.9L out and put in a 2V carbed 302 just torque alone was worth the change and gas mileage is about the same. I have more than enough HP for the 35" tires and mods now are easier and more noticable.

Hope this helps

 

...work properly? I put it in the water and heat it. Abouve ~94C-96C (i don't know how much in F) it start to open, but the water start boil nearly that thermostat open full. It is correct?

 

Zayaz, you can hang the T-stat in the water with a piece of string. When the water temp gets to 94 C the T-stat should open & fall to the bottom of the pan.

 

...when it came to me and I put it we'll see...