temp guages problem..

[WannaXP8]

ok, so heres my problem, I went 4 wheeling, im some serious deep mud, and caked the radiator with mud, cleaned it off, got all the mud out, and so on, well then the temp guage started to climb, and fall, climb and fall, so I was thinking thermostat, so I changed it, with no luck it still rises and falls, so I was like ok, so Ill change the temp sending unit, still rises and falls, and ok, so heres the weird part, I have the outside temp guage up on the roof, and I was watching it yesterday, and it was 82 degrees outside and the temp guage read 109..and as the temp guage on the dash (motor) went up, the outside temp guage went up, and when the dash temp guage fell the outside temp guage fell..so its like they are crossed or something, cause they are trying to read with each other, so what im wondering is the temp guage in the dash for the motor even reading right, or is the outside temp guage wrong..so Im wondering if im chasing a problem that doesnt even have to do with a cooling issue or should I be chasing a eletrical issue?

 

[IAmTodd]

thermostat possibly?

 

[cjbarron5]

sounds like an electrical issue (ie bad ground or along those lines)remeber the temp sensor works on resistance so a bad or internitant ground would affect it

 

[WannaXP8]

I already changed a thermostat, do you think that the guage is just bad, or do you think the motor is really getting that hot? So how would I check the guage?

 

[RiverRat]

You sure you got all the mud off the condenser, radiator, engine, exhaust? How is the cooling fan/clutch? Hook up a scan tool and read the temperatures. You could get a infared "point and shoot" temp reader. Those things are cool

 

[WannaXP8]

so if i get one of those point and click temp shooter, where do I point the temp guage at?...I need to have this thing fixed by friday..d

 

[BillWms01]

Let me say I don't know anything about the 5.0L V8, but the temp gauge on my '97 with the 4.0L OHV acted the same. Make sure you changed the right temp sending unit.

I changed the temp sending unit too, but only after a little adventure. On the 4.0, there's two temp sending units close to each other. One for the dash gauge, and one for the computer; not the same part number. Needless to say, I got the wrong one first, but the wiring connector wouldn't plug in, so I took it back and discovered it wasn't the right one.

The new sensor (along with new thermostat while I was right there) fixed the problem.

 

[WannaXP8]

ok, so is there anyone that knows about the 5.0..or can anyone help me..Ive changed the one on the top of the motor..by the driver side head..and that doesnt explain why the temp guage for the motor, and the outside temp guage are both readin like the same at the same time