Cooling System Possible Prob
 

1994 Ranger w/ 2.3 @ 146,000. Just got it from a guy in N.C. and am doing it up. New timing belt, water pump, theremostat, oil change, tranny fluid change, rear end fluid change, plugs, wires, coolant flush etc. what i did was i pulled the rad out when doing all this and flushed it through and it has great flow to it. put it back in and have been running it the last 3 days. i put a 16lb. cap on it to replace the orginial which was a 16 also. the prob is the cooling system never gets too pressurized. we're talking maybe 5lbs pressure here and my temp gauge fluctuates up and down like the engine is warming up, openeing the thermostat and then running at the 195 degree mark, going colder than 195 and then warming back up again. i think the gauge is out of calibration for one thing but i've never seen a cooling system not pressurize like this one before. no visible leaks...water pump sealed along with thermostsat housing and nothing leaks on the ground and no wet spots on the block from underneath that i've seen. got any ideas? i burped and burped and burped and nothing. is this just the 2.3 thing to do or is there something actually wrong here? thanks

Sound like you may have a bad thermostat. They have been known to be junk straight out of the box. You did use a 195º thermostat?

I'm thinking that with the cooler weather and the great flow through the system, it's just cooling too efficiently with a stuck open thermostat that won't keep the coolant in the engine long enough to get warm.

Wouldn't hurt to do a cooling system pressure test too. And get one of those cheapy cooking thermometers for about 5 bucks, you can stick it in the coolant and get an accurate reading of the temp that way and cross check it against the gauge.

ya 195. and i've heard the same of them being bad right off the bat. what i still don't understand is why the system won't pressurize?? all the vehicles i've worked on have always had great pressure...fire 'em up and the return hose gets tight. whats up with that?

Like I said, do a system pressure test. It either has a leak that won't allow it to build up pressure, or it's not getting hot enough to build up pressure.

well the other thing is we hooked up our genesys to the truck after sandblasting the terminals in the truck and it established a connection but we coudln't get any readings. never had that happen before so we can even see what the temp sensor is doing?!?!?