Cooling Fan operation for 2000 Protege
 

Hello everyone,

First of all, I’ve word-searched the forum and read all (4) posts about the Protege’s cooling fans. But I still have questions concerning mine. Hopefully someone who knows for sure will respond.

I bought a 2000 ES for my daughter. It is in excellent condition with only 49000 miles. But it was a salvage title because it had been in a minor front end fender-bender and subsequently repaired. I want to get everything I can think of squared away before she goes off to college next month so I’ve been doing all the maintenance stuff ie. sparkplugs, tire rotation, oil & filter and a transmission fluid change etc .

Anyway I am telling you all this because the only thing I am still unsure about is the way the cooling fans are operating. It has two cooling fans. Alldata labels one as the A/C condenser fan and the other a radiator fan. When the engine is started up cool in the morning, if I turn the A/C on, both fans immediately run continuously. I can understand why the A/C condenser fan would run, but why does the other radiator fan run along with it unnecessarily even though the engine is still cold?

After a while and when the engine is warmed up, both fans then cycle on and off together apparently with the A/C compressor cycle. At this point I would think the radiator fan would run controlled by the coolant temperature and I would also think the condenser fan would be the only one cycling on and off with the compressor (and preferably just running continuously when the A/C button is selected). Doesn’t that seem logical?

But like I say, both fans continue to cycle on (and they are pretty loud too) and off together about every 20 seconds. Why have two separate [big roaring] fans if the the system is then designed to run them always together. It would be more sensible if the A/C condensor fan would run continuously anytime the A/C is selected... and the radiator fan was controlled by temperature and would run or not run independently. This is how all my other cars electric fans seem to work.

The 4 cylinder 1.8 liter engine runs very smoothly in or out of gear at about 700 RPM. But when the A/C and the two fans come roaring on, and the RPM jumps to 800 rpm, things then vibrate excessively making the hood shake along with the unpleasantly loud fan noise. Is this normal? This seems unnecessarily poor scheduling of the cooling fans.

My question is: Is this how it is suppose to be? Or is there maybe a temperature sensor or something not right? I noticed it also takes about 3 times longer to warm up than my other cars. This also seems odd especially since the Protege makes the cooling fans run on the cold radiator and engine.

Or... if this is how all Proteges are designed to operate the cooling fans, is there a way to make the system operate in a more sensible manner?

Or... since both these fans turn on and off together would it be OK to just unplug one to cut the fan noise in half and still have adequate cooling. It seems like overkill anyway to have two fans, especially considering that during the cycling they are sometimes both completely off for 20 seconds. They should provide nice consistent moderate airflow rather than this on-off-on-off all the time.

Is there someone who knows the Protege well and can tell me for sure? Maybe a mechanic who sees them all the time and can give me some solid information?

Thank you for taking time to read my lengthy post and advise me on this.

Bob

P. By the way, This is an extremely well designed, user-friendly web-site. My compliments to the webmaster.

the operation of the fans you describe is normal.. my 00 protege ES cycles through the fans every 10seconds or so though, instead of 20.

My idle's are between 500-800 too.. so that's normal as well. The normal idle the manual describes is 700rpm anyway..

Can't comment on the vibrations you describe.. although every once in a while I'll get alot of vibration when I'm stoped for some reason, it never lasts long.. mabye 5seconds or so.

The vibration you get when the fan engages is from the slight load that is put on the engine during its on off operation, this is compounded further with use of the AC and also the AC fan kicking in as well.

When your engine is at low RPM , remember its alternator energy output is at its lowest.

If you have access to volt meter tools you can observe the power balancing when the fan and AC is engaged.

I had the problem for a while but did some modifications to resolve it, but rest assured so long as the vibrations arent harsh, they are normal.

Mazda Pro. 2001 ES 2.0
190,000 km and going strong :)

Thanks Lozz. And you too Omron.
Thanks you guys.