over heating !!

[kwiksilver]

this is a 89 lebaron with a 2.5 turbo I and auto trans.

the temp gauge is getting to almost hot and the fan will not come on under normal conditions.

With the A/C on, the fan will engage.
if you un-plug the temp sensor the fan will come on.
I have replaced the temp sensor and the fan relay with no change.

Ideas, suggestions and comments are welcome

[turbovanman²]

Which temp sensor, the one at the thermostat housing?

[cordes]

Depending on how hot your gauge reads for a given temp it may get pretty toasty before the fan kicks on. They don't kick on until 22x*.

[kwiksilver]

yes, simon... its the 2 wire sensor at the thermostat housing. I replaced the sensor with a used one off a parts car and replaced it with a new sensor from Napa, fan still doesn't come on.
I am wondering it its a sensor problem at all or do I need to use a OEM dodge sensor.

Cordes, thats the point.... fan is NOT coming on at all, under normal conditions and the engine is overheating.

I hooked up the scan tool and found no codes stored. I was able to activate the fan relay with the scan tool as well.

[JamesL]

That's pretty odd....Do you have anyway to verify the actual tempature? Clearly the relay is working and being switched or it would not turn on when you unplug the sensor.

[tryingbe]

What does the scan tool say the temperature is?

[kwiksilver]

I agree, it is odd

I bought an aftermarket temp gauge but haven't found a good place install it yet, the threaded fitting, on the aftermarket gauge is larger than the threaded hole in the cylinder head for the sending unit for the factory gauge.

I didn't think about checking the coolant temp with the scan tool. I had the key on and engine off while I was checking codes and playing with actuating the various relays and switches.

[Mysterio]

My relay or fan took a crap on me and I just bought a new one and wired it into a manual switch

[turbovanman²]

Ok, then check coolant temp with the scan tool, if it shows toasty and no fan, wiring ok, I would say computer took a dump.

[kwiksilver]

Ok, then check coolant temp with the scan tool, if it shows toasty and no fan, wiring ok, I would say computer took a dump.

that was gonna be my next step. I am leaning toward a faulty SBEC, since the cooling fan was working then all of a sudden stopped working.
I still need to double check the wiring.

However I was thinking that since I could actuate the fan relay with the scan tool through the SBEC that the circuit was good. or is that NOT a correct assumption?

[turbovanman²]

You could hook up a manual switch for now, that way you won't kill your engine.

[shadowdude]

I got tired of chasing a bad relay on mine so thats what i did ,ran a manual fan switch in place of the relay ,this way here if it over heats its my own fault for not checking the gauge.I like having manual control over the fan ,good to keep in on for hard runs or in hot traffic.

[turbovanman²]

that was gonna be my next step. I am leaning toward a faulty SBEC, since the cooling fan was working then all of a sudden stopped working.
I still need to double check the wiring.

However I was thinking that since I could actuate the fan relay with the scan tool through the SBEC that the circuit was good. or is that NOT a correct assumption?

That probably is a good assumption but still doesn't hurt to trace the wiring, JUST to be sure.

[kwiksilver]

one more question.... I have a spare SBEC from an 88 2.2L turbo I /5spd car.
will this computer work as a spare for testing in my current 89 T I auto car?

[raccoon]

yup.

[tryingbe]

one more question.... I have a spare SBEC from an 88 2.2L turbo I /5spd car.
will this computer work as a spare for testing in my current 89 T I auto car?

For idle, sure. 2.2 computer will run lean and have too much spark timing for the 2.5

[raccoon]

its just for testing the cooling circuit right?

[kwiksilver]

Very interesting ....

Replaced the fan just for giggles and it works now. I don't understand it, but it works.


engine warms up, fan comes on and cycles like its supposed to.

[turbovanman²]

one more question.... I have a spare SBEC from an 88 2.2L turbo I /5spd car.
will this computer work as a spare for testing in my current 89 T I auto car?

BTW, you have a SMEC, not SBEC, SBEC's started in 90.

[raccoon]

Very interesting ....

Replaced the fan just for giggles and it works now. I don't understand it, but it works.


engine warms up, fan comes on and cycles like its supposed to.

motor might of had a dead spot on the armature.