Help! Cooling fans, what's the scoop??

[vettebob]

I live in the desert southwest, and do not want my car running at 230 plus degrees. They can talk all they want about this being good for engine wear, but I am a mechanic with 40 years experience, and I'm not buying it. It is all for smog purposes, and besides, at 230 you only have a very small margin 'till redline if something should go wrong, (like a traffic jam in Phoenix in August, or climbing the long hill on the freeway coming out of Indio, California.)
So, there is a lot of confusing information about fan switches, and I would like to "cut through it". I would like BOTH the fans on my '87 Corvette to come on at around 170 degrees. Some sites say they have a switch that will do that on both fans, other sites say that the new switches only work for one fan, etc. etc. etc. What is the actual proven procedure to get BOTH fans to come on at about 170 degrees automatically??

(I plan on running a 180 degree thermostat, and my car is an '87 with the Z-51 option with dual fans and a three row aluminum radiator.)

Thanks guys!!
vetttebob

 

[BADDUCK]

O K, here's how I did it. First of all it really doesn't make a lot of sense to turn both fans on before you give your thermostat a chance to open and the coolant to do it's work. So, here's what I did and everything is automatic.
Assuming you have a 180* stat, remember your main fan comes on when you turn on the A C or when coolant temp reaches 228* it is controlled by a pressure switch and the ECM. What I did was put a switch/sensor in that turns on the aux. fan at 200* rather than 236*. That sensor is between plugs 1 and 3 on the drivers side head on my 1989. This has worked well for me for over two years in Arkansas heat and humidity.

 

[vetteboy86]

Buy a new fan switch for the auxiliary fan. Have someone change your ECM settings for fan on temps. This is the most hands off way to do it. There would be no switches to remember to fiddle with. The programming may cost an arm and a leg unless you know someone that will do it for you.

 

[boomdriver]

I live in the desert southwest, and do not want my car running at 230 plus degrees. They can talk all they want about this being good for engine wear, but I am a mechanic with 40 years experience, and I'm not buying it. It is all for smog purposes, and besides, at 230 you only have a very small margin 'till redline if something should go wrong, (like a traffic jam in Phoenix in August, or climbing the long hill on the freeway coming out of Indio, California.)
So, there is a lot of confusing information about fan switches, and I would like to "cut through it". I would like BOTH the fans on my '87 Corvette to come on at around 170 degrees. Some sites say they have a switch that will do that on both fans, other sites say that the new switches only work for one fan, etc. etc. etc. What is the actual proven procedure to get BOTH fans to come on at about 170 degrees automatically??

(I plan on running a 180 degree thermostat, and my car is an '87 with the Z-51 option with dual fans and a three row aluminum radiator.)

Thanks guys!!
vetttebob

I lived in Phx and before that was desert SoCal...so I understand the concerns of life in the desert. My motor is modified and completely pukes out at 225, so I like to keep it around 200 for some margin AND performance.Summer in Phx afternoon traffic is beyond brutal. Its no wonder that GM used to have a proving ground on east side for many years. I've read many reviews on cars and bikes that utilized the extreme heat there to beat up their product and test its limits.

I tried everything and ended up with a hypertech chip (got a custom now) that turns on the main at approx 175. Manual switches are a pain in the a** and are prone to failure besides having to run wires. New temp sensors trick the ECM with a false signal but can be effective especially on the aux fan. The aux fan sensor is just a ground, so thats very easy to do with a manual switch. Beware toggle switches...you may want to un-do the switch mount someday, so avoid holes in the dash trim....
There is no better main fan....I tried and none move more air than the GM stock unit.
Install a 160 stat so the coolant is moving, get a chip and that will do as much as anything with the stock radiator and keep it simple.

My next purchase will be a BIG 2 or 3 row fully aluminum radiator, an electric water pump, and hotel reservations in 29 palms in August....

 

[BADDUCK]

The new temp sensor doesn't trick the ECM. The aux. fan is completely independent of the ECM. He doesn't need a a new chip, that will only affect the main fan. A new sensor is about $15 and that's all he needs.

 

[vettebob]

Good info, thanks!

Thanks for the input guys. I appreciate it and hope I can reciprocate some day.

vettebob