ive been looking at other posts and such thinking but im still unsure. we have replaced the fan, fan relay, temp sensor, thermostat and still the fan is not coming on and the car will get to 220. the upper hose also gets very hot and hard..almost bursting. where and wht else should i check?

 

update on where im at. found that the fan was binding up on the shroud, new fan motor, relay, stat, temp sensor on the front of the intake under the throttle body. there is another sensor right next to that one that i believe to b a bad fan switch sensor. drove the car, know that fluid is circulating great, no restrictions and no colapsing hoses. temp got to 250 b4 i shut it off..fan never kicked on but the new fan motor was smoking. when using the test light to test and see if binding on the shroud burned up the new fan motor the fan kicks on only if using the test light on it. so if the fan motor is getting power to make it smoke why wont it kick on even after the binding issue was fixed. i guess that the fan switch sensor is just not reading temps.

 

I know this is going to sound dumb, but I'm having cooling problems in my son's 1986 Camaro Z28. Had a new long block installed with a new water pump. Used the same intake manifold and all other tinand same radiator as from the old engine. Old engine was a 305 installed a 350. It is over heating. I nor the shop that installed can figure out why. I am going to replace the radiator, temp sensor unit and thermostat. If that doesn't work then I'll R&R the water oump. But back to your problem. My shop told me if the coolant level wasn't high enough it wouldn't kick the fan on. I don't know sounds fishy, but check that. Good luck.

 

There is a fan switch in the pass side head, between #6 and #8 spark plugs - have you checked it?

This is a dual fan setup right? On the dual fans, as I understand it ... the ECM controls function of the primary fan - so this should be based off the cts that is in the thermostat housing. The ECM gets temp reading from the cts and turns on primary fan.

The secondary fan is controlled by the fan switch in the pass head, and by the A/C - second fan should always run with A/C.

Again - this is what I've read - I have single fan so I'm not experienced with dual fans and the TPI cars.

 

the one thats on the block on the pass side back there between 8 and 6 was a knock sensor. at least thats what orielys said, we pulled it, antifreeze came out took it up there and looked it up in the comp and the book. they said it was a knock sensor.

it is a single fan setup, coolant is full, has a new 16lb lock cap. if u trace the wires from the fant to relay then from there they go to these sensors that are side by side right under the throttl body, one of which was the temp sensor which we replaced.

 

Yes - sensor in the block is a knock sensor - but above it IN THE HEAD (not the block) is the fan switch - it has the same type connector with one single wire. But like I said, I'm not familiar with the TPI and how that functions with the fan.

 

there is no sensor n that spot, its plugged with a pipe plug

 

You are right - there is no fan switch that I can find on the wiring diags for your car - looks like the ECM has sole control over your single fan, I'm assuming it gets it's info from the coolant temp sensor that (I think) is in the thermostat housing.

 

the temp sensor is not in the thermostat housing, its just below the throttle body. we replaced that and still no worky. i was thinking that it had to be a computer prob, everybody has given up on this car, even a gm dealership. lol. i was fixing it for a guy, it works now via a flip swith hahahhah

 

The single fan on my 86 had the same problems, the stock fan temp in the ecm is like 235degrees. but the gauge would show 240 before it would come on. May be worth putting an adjustable fan controller on it so you can adjust the temp. I got one from Flex a lite which was a little expensive but works perfect. Might be time to do a late model 3rd gen dual fan or ls1 fan upgrade. They work better hands down.

 

we actually ended up not putting in a toggle but took 5 mins and hardwired the fan to always on while the key is on. the guy was pleased that it was finally good and he reached an end.