Not another fan question

[tonysfiat]

I know this has been discussed at in great detail, and I have searched this site, which has helped me immensely.

here is the jist of my problem.

The other day when the temps were in the high 90s my 79 automatic spider temp gauge was reading over 190 close to 240 that is when the fan kicked on. Scary. Well earlier in week I had removed the top hose for who knows what now, so I assumed I got air in the system. I bled the system using the prescribed methods jacking the car up etc.

Well after several attempts I believe I got it, however the fan does not come on, the bottom hose is hot the radiator is hot also at the bottom . So I believe I am getting circulation. Could it be the temp. sending unit, how to I do a diagnostic on sending unit, or just go ahead and replace it.

PS

this am i removed the t-stat and checked by placing in hot water it performed as should opening between 190 and 200.




Thanks

Tony





Thanks in advance

[mbouse]

FWIW- i have a manual switch on my dash wired parallel with the rad fan switch, so i can turn the fan on when ever i feel like it. i believe i have "properly" functioning, tested t-stat and rad fan switch. i believe i have all the air burped out of the system, i believe i get good circulation....but I too see times when the gauge dives for the boil over point....hence the manual switch.

i believe you went with the electric choke when you changed your carb, right tony? how did you cap off those coolant feeds for the water choke? are either of those leaking?

something you may wanna try is to put a TEE fitting into your heater core hose that runs between the head between #3 & 4 cylinder and the heater core tube on the fire wall. Get one of those radiator flush kits and install the tee in the middle of that hose. this creates a new highest point in the coolant system that is accessible. if you add coolant at this point, you no longer need to jack up the car. all the air escapes out this tee where you are adding the fluid.

additionally, don't forget to open the heater control valve when adding coolant.

[punes]

I just sent through the same problem. Play with the wires leading into the temp sending unit...when I did the fan kicked on and when I let go it went off...I ordered and new unit plus all new hoses and plan to change them all...for now I installed a bypass switch and operate the fan manually from a switch on the console.

[So Cal Mark]

you'll need an ohmmeter to test the fan switch-you should have continuity above 190F