HI
does anyone know how to check the radiator cooling fans?
my drivers side fan comes on when the air-conditioning is on or when sitting in traffic and the temp goes up! When is the passenger side fan supposed to come on ? Thanks

 

Your profile is blank. What year, what motor?

 

Your auxiliary fan comes on at a higher temp than the main fan. If you merely want to verify that the fan motor works, jump 12 volts to it as a test.

RACE ON!!!

 

Sorry - will fill in profile
1993 Ruby 40th LT1
Thanks

 

I have my radiator, upper/lower support, along with the A/C condenser, and fan housing, out. I had a AC/DC converter, and tested both fan motors. I think I picked this converter up at Radio Shack a long time ago for a few bucks. It works good, has an on off switch along with terminals, this way, I don't have to mess with the battery....

 

I believe it comes on around 236-238* for that year model. You can let it idle w/o the air on and see what happens as it heats up. I tested mine that way this summer.

 

HI
is there a way to change the temp at which the fans come on?
generally at 55 mph my temp gauge stays right in the middle...lately when moving slow or in traffic the temp runs right up to the point where the fans come on... I have changed the thermostat and flushed the system...what might be causing the wild temp variations?
Thanks

 

Depends on the year. You can get a custom PCM or low temp sensor/switch.

 

What temps does the digital display show in city traffic and at freeway cruise speeds?? The analog temp gauge is not linear so "in the middle" maybe 30 to 40 degrees lower than when it move 1/8" higher. The digital temps are much more accurate and it would help if you provided the readings you see.

It's common for operating temps to be around 190 to 210 degrees if everything is working properly. In hot weather or sitting in traffic may cause temps to climb to 235 or so but the fans will come on (again if all is working right) to drop the temps quickly. Typically, turning on the A/C should result in a drop in coolant temps.

C4's are known as "bottom breathers" in terms of airflow through the radiator. Cooling air come in from under the front plate and into the front shroud. Air has to pass through the A/C condensor before going through the radiator.

It's very common in these cars for dirt and debris to clog up the passages in both the condensor and the radiator. That effectively cuts the airflow and results in higher coolant temps. If you look up under the front of the car, you may see all sorts of junk up there.

One good way to clean the debris is to use a garden hose and spray a stream of water through the radiator from the cooling fan side. This may take a few tries to clear things up. Jsut be careful to not get water on the OptiSpark!! You can also use a vacuum to suck out debris from between the radiator and condensor. Look through the radiator shroud at the top passenger side corner and you can see into that area.

To quickly test operation of both fans, use a paper clip to jump pins A and B in the ALDL and turn the ignition switch to RUN but don't start the motor. This will force both fans to run.

The driver's side fan is the Primary fan and the passenger side is the Secondary fan. When the A/C is turned on, the secondary fan should start if the primary fan is on.

The primary fans starts when coolant temps reach around 226-228 degrees and will shut off when coolant temp drops about 40 degrees. The secondary fan starts when temps reace about 234 degrees and shuts off when temps drop about 40 degrees.

Inputs to the ECM for fan operation comes from inputs from the A/C system, cvoolant temp sensors, engine oil temps, vehicle speed sensors, and engine RPM. Each fan has a relay that provides power to the fan motor when necessary.

 

Guys!!! Thanks Very Much!