I'm hoping someone has had similar problems as I'm having and has been able to resolve their issue. I have a 1999 olds lss and the cooling fans don't come at all when the engine gets hot. But they do come on when I turn the A/C on. so I guess that tells me that the fans are not blown. The temp gauge doesn't go into the red zone but I'm sure it'* not too good for the engine to be running so hot most of the time. Any ideas of info on this matter would be appreciated.

Jeff

I had the same, identical problem

You are experiencing

1.) defective cooling fan swtich ... it'* kind of, half temp sensor (though, NOT the actual temp sensor) and half switch ... NAPA will find this for you. i think it was like $10.00, my mechanics installed it for me, i'm not sure where it is but i know it'* a solenoid looking thing on one end, that'* threaded, with an electrical connector on the other end.. kind of same size as a common spark plug.

2.) afterward, I'd recommend bleeding your cooling system - top, driver'*, front on the engine near air intake plumbing... there'* a flat head screw on top of the thermostat housing, visible without the plastic engine cover on the motor. you must do this while the engine is hot, and the cooling fans are working properly - and on. my car still ran a bit hot after the fans started working - I burped it a few times, and it made it much cooler - all the time.


good luck, have fun!

- Joe

also, the reason the fans work with the a/c on - is because - that defective switch gets over-ridden as soon as you turn the a/c on... in other words, the a/c requires the fans come on - and stay on - Otheriwse; they cycle on and off as the car heats and cools. (sitting in traffic, they come on. driving down the highway, they shut themselves off. this is what your car is not doing right now. but you know that)

Low speed fans come on at 216F, high speed at 228F or whenever the AC is turned on. This can seem very hot on the temp gauge.

If you can, scan the car and see what the pcm temp is reading.

thanx for your reply Joe. I called NAPA and the dealership and they both said they have an item thats called a temp sensor which is located on the drivers side intake manifold. it retails here in Canada for about 45 bucks. They described it as being about 2 inches long with threads on one end with a conector on the other. Does this sound like it may be the part you're describing?

Thanx again , Jeff

it does sound like the part,

it is technically a temp sensor - this one'* only function is to relay temperatures to the computer, then, the computer decides what'* up and it tells the fans to come on/off, high/low.

i'm not sure if it also communicates readings to the guage - the auto parts store may well have the part, and not precisely know what it does - or I could be a little off, however, it DID fix MY cooling fan problem completely - i tried replacing relays and all types of other crap that wasn't broken first.

at least i have spare parts now : )

if i recall, i went into the store asking for a ..."fan switch, or whatever makes those fans come on",,, and left with a temp sensor.. i should have the recipt.

96+ temp sensors are a dual element. One element feeds to the pcm, the other to the cluster. Therefore one can be bad. However the best way to check that is to scan. If you can't scan... mmmmmm I wonder what resistance it would take to give you the temps needed for fan turn on. You could use a cheap resistor to test the sensor without having to buy.

word.


thing is, he said his fans work with his a/c.... so, the fans turn normally.

mine did the same thing.

my shot in the dark turned out to be bingo on this one, he and i have the same car - stands to reason (and it'* cheap enough) that it'll be successful for him too.

just got home, i was listening to the fans - it was like music.

I'm totally with you. But when a sensor is $45 because he'* in Canada and a scan tool or resistor may help diagnose it for less. I'm all for it.

The fans working with AC means that the pcm can turn on the high speed fan relay. Which also means it "should" turn them on when it sees the right temp which is on the right track with swapping the sensor. On the chance a test is cheap/free and possible, I try and suggest it.