Engine Temp. Readings?

[91explorer1009]

I have been searching all night, but haven't found a decent answer. I have been having a lot of problems with my cooling system on my 91. I know its not a very accurate reading, and I am not just going by this. But, what is the most normal temp. gauge reading. As far as placement of the needle. Is it right on the N, straight up and down between the M and the A? What does your truck run at? Everyone please chime in. For 4 years mine ran right at the N in normal, and never really moved too much. After work, (replacing t-stat, sender/sensor, new coolant), it is now running differently. I have done everything, from burping to weep hole to inclinen parking. I have done my searching. I just want to know what the "normal" gauge reads in a first gen. Thanks in advance guys, I just want to know if I was bad for 5 years and right now, or vis versa. Thanks!

 

[Potomac30]

Mine ran right a N, but after the last T-stat change, it fluctuates between N and M - close enough for me. You said two things: "I have been having a lot of problems with my cooling system" - what were they and are they fixed now? And "After work, (replacing t-stat, sender/sensor, new coolant), it is now running differently." Differently as in better, worse, how?

 

[Maniak]

Our '92 was reading at the N when warmed up (195F thermostat).. I rebuilt the motor and put in a new temp sending unit. After the rebuild+new sending unit I was thinking I really messed something up since the temp gauge now read around the A in Normal (way right of where it used to be). I have since added a temp gauge (ISSPro) with a sending unit in the heater hose that comes from the head.

Now watching the both gauges together I can see that 180F reads about at the O/R on the factory gauge and 195 reads at the A.

Sooo, in short.. Where in the gauge it reads doesn't really matter.. What matters is that it is running where it "normally" should on your vehicle as variations in sendnig units will really change how it reads.

~Mark

 

[MrShorty]

It seems that the trouble with dash gauges is that they aren't really "calibrated," so you can get significant variation from vehicle to vehicle. When I really want to know what temperature I'm running at, I backprobe the computer's ECT circuit (which should have a good calibration on it and a good, constant reference voltage to it). Then I can compare the voltage drop to the published tables (BrooklynBay I believe has posted a link to this table several times) and really see what temperature I'm running at. If you pay attention to what the ECT is reading and the dash gauge, you can even get a resonably "calibration" for the dash gauge (if your dash gauge is consistent enough).

Basically, I'm proposing the same thing Maniak propose, only this way you don't have to go out, purchase, and install a third temperature sensor.

 

[Anime]

For a "normal" operating temp, having the needle straight up and down is probably where it's supposed to be, but a lot of things vary the reading. Just changing the thermostat will do it, and cooler weather will usually give a reading to the left, hot weather, especially with the A/C on will make it go to the right. You really would have to find out what the actual temp is to figure out what temps are in what locations on your particular gauge, but in general, if it's not going past the "L", it's ok...but it's better if it just varies slightly to the left and right of middle, or even just stays in the middle and barely moves.

My original factory 'stat kept the needle in the middle ALL of the time, and as soon as I changed it, the needle moves quite a bit now. Even with lots of coolant/'stat/water pump changes and using a Motorcraft 'stat, it's never gone back to reading solid, but it seems to be "accurate" in the sense the temp reads warmer or cooler when that's probably what it should be. Just get used to what yours reads, or get a real temp gauge if you want.