How to test my radiator fan?

[iridius]

I want to test my radiator fan, when I run the car and put the AC on I don't see it spinning, but it's hard to really see in there and the car makes so much noise I can't tell what part is spinning.

Can I test it with the car off by jumping it or something? What's the best safe way to do this?

thanks.

[CREWZIN]

If you can get under the car, you'll see that there's an electrical connector about 6 inches from the fan motor. Pull that apart and you can use a ground and a hot wire to test the speeds of the fan. The middle pin is the ground and the other two are the speeds of the fan.

[mdfrodolives]

Iri, I think it was Cruzin who had the idea to paint a white mark on one of your fan blades. Just reach in there (with the engine NOT running and nice and cool to the touch) and slap a bit of white paint on a part of one fan blade that you can see. Let it dry.

I used a mirror to see if my fan was running cause I couldn't really get a good eyeshot otherwise.

However, you should be able to hear your fan running on high speed with the car at idle and the A/C turned on. My fan makes a very noticeable whirring noise under these circumstances. And if your fan isn't working up to snuff, you might be feeling some engine sputtering at idle with the A/C on at the same time. Do you?

Prop up your hood, then with your engine cold, start it up and go round the front and listen to all the noises. Your fan should not be running at this point. Now go back to the front seat and turn on your A/C to high cool. Now go back round to listen to the engine area. You should now hear a very noticeable difference--a noticeable whirring fan noise. If not, drive the car for a while to get it to normal temperature. Park it and turn on the A/C and go round to the front of the car and listen again. You should definitely hear the fan running.

Tim

[alanrw]

Also, a good strong flashlight will help unless you are on the driveway on a sunny day.

And if you don't want to mess with paint, a piece of masking tape on a fan blade will also work.

alan

[iridius]

ThNks for the info and ideas tho I'm new to All this. so when I disconnect the plug what ki d of wire do I run? And where from (the battery terminals?) thanks. I took the grill of then started to take the front metal piece off ( I wanted to test my impossible to reach low pressure port with an artic freeze tester recharger but as I got the 5th bolt off I chickened out because it felt like if I took the 6th one off the whole radiator (including) the fan would just be dangling. I will have to read more.

[CREWZIN]

OK, two fairly thin wires about 6 feet long (gives you extra play to move around). All four ends of the two wires stripped bare of the insulation (about half inch). One end of one wire to a ground, one end of the other wire to a positive (like the battery). DO NOT touch the far end of the battery wire to anything yet). Take the two wires (while under the car) and carefully touch the grounded end to the middle pin and even more carefully touch the positive end of the other wire to either of the other pins. The fan should come ON in either the slow or fast mode. Then reverse the outer wire to the other pin and the fan should change speed.

You sure you want to do this by yourself?

[iridius]

Hah I love the last line. Thanks for the concern. I will give it a shot. I've worked with electronics a bunch. Just smaller scale. So I'll make sure to measure twice and cut once. I'll head to home depot on Monday and grab some wire to try it. Any gauge/type in particular u recommend? In term of a ground is there a spot on the car that's a dedicated ground I remember reading of some bolt or screw for that purpose on some other car. I'll ask at the store too. Thanks for the advice and warnings.

[CREWZIN]

As far as wire gauges, I'm really not into the different sizes but to guess, somewhere between 14 and 17 gauge. Single strand or multiple doesn't mater but single stand is easier to work with. Grounding; many different points on the engine or body. Anything grounded that you can wrap the bare wire to.

[VNT]

When are people generally running into toasted fans?? IE how many miles?

I assume people who do more local driving will tend to have the fan fail sooner versus someone who has a highway commuter.

Also would it be good idea to pack the connector with some dieelectric grease??

I thought some had contact issues at the connector due to corrosion.

[mdfrodolives]

VNT, my fan went out at about 60,000 miles, if I remember correctly. At any rate, I remember that when it went out I thought it was way too soon. It ended up causing too much pressure on the high side of my compressor--due to lack of cooling at idle--and ruptured an A/C line. So the fix was not merely a new fan. I also had to have the A/C worked on--and that wasn't cheap.

60,000 miles is way too soon for such a problem. But it is apparently a very common one with our cars. Now that I know what can happen, I'm very conscious of the fan, and know the symptoms when it does go out; and if the replacement was no better than the first one, I will replace it myself.

Tim