Cooling fans not coming on

[dbstrass]

In the process of resurrecting my 93 SSEI after running at idle for awhile the engine was pretty hot. I noticed the fans never came on. I unplugged the temp sensor and both came on. So would the problem be the temp sensor, thermostat, or relay. I am not sure what the actual engine temp was because my Cluster only works when it wants to, usually when its warmed up and going down the highway or when I mat the throttle. Any advice would be greatly appreciated.

[Tech II]

Well, it's not the relay or thermostat.....

Those fans will not come on until the temp reaches 220F....

[dbstrass]

Suppose I'll have to wait until she's road ready to get up to temp. I sure thought after 15 min. at idle they would kick in. I'll post more later as I go. Right now I am replacing brake lines. She sat for 2 years and started up first try, so I am starting from the ground up. I see many beers and busted knuckles in my future !! 93 SSEI

[Tech II]

Yeah, it's fun, if you have the time, to put one of these cars back together......

[dbstrass]

With climate control on defrost should they run ?

[Tech II]

Yes, but only if the compressor clutch engages....

[dbstrass]

Drove today and temp read 260 and no fans came on. My guess is a temp sensor. Looks like I Have a coolant sensor on the radiator and temp sensor on manifold tucked in under MAF sensor, if I unplug it, fans kick on.

[Tech II]

The sensor in the radiator, is only a LEVEL sensor.......

The sensor under your thermostat housing, is the CTS sensor.......there is no separate sensor for your guage......so, either your gauge is off, or you have a bad ECM.....you would need a scan tool to see what the actual coolant sensor reading is, and compare it to the gauge reading.....

[dbstrass]

OK, update time. Cooling fans are now running as they should. The engine pulses at idle and changes rpm when brakes are applied. Runs fairly good at low rpm but stalls when matted. I added seafoam to crank case, fuel and a little splash through pvc. Still want to do plugs and wires next and see what that does. Fuel filter probably needs replaced also. PVC could be bad as there might be a vacuum leak The only dummy light showing up is the low coolant warning, and I checked radiator and overflow both are full. Any ideas to throw at this thing would be greatly appreciated.

[Tech II]

Well, if the low coolant light is on, and the radiator is full, the sensor is bad or contaminated(can check circuit, by disconnecting the level sensor, and light should go out)......you can put a new sensor in, but if that coolant has not been flushed in a long time(with your year, fluid should have been changed 4X's), just putting in a new sensor, is not the answer.....because the old coolant can contaminate it again....could happen right away, could take time, depending on the condition of the coolant....

[dbstrass]

Thought I would send an update on this project. Replaced rear brake lines ( Leaking ), Coil packs (One had Cracks in it ), Plugs (Old ), Plug Wires (Old ). Took off throttle body and cleaned out 20 years of gunk. Took off EGR cleaned it and all ports, lots of carbon. CAT is gone and replaced with straight pipe. Cleaned all sensors to throttle body and connections. Replaced front sway bar attachements and bushings( Cause they were gone ), Flushed engine and oil, also cooling system flush, ( Which produced a lot of greasy coolant.) I went ahead and used KW on it just for the ease of it to see what would happen. I now have no white puffs coming from the exhaust, and it runs awesome ! I am not sure if I had a head gasket leak or Intake leak, but it's working for now. Going to keep checking oil and coolant for cross contamination and see what happens. For now I think I am going to get some plates and start driving it to work and back and see what other curve balls she throws at me.