A/C fan sound when the A/C is off.

[jakesc7]

I have 06 Explorer, XLT

When I drive around for a while and then slow down or come to a stop, and then reaccelerate sometimes I hear this exhaust fan like, revving up, howling sound coming from my hood. Its the exact same noise that my car makes when I first turn on my A/C, you know that noise that sounds like your engines revving up more....The only thing is, in the situation i described my A/C is off. Any ideas why I would hear that noise?

Cooling system, cooling fan, some sort of a/c belt, sensor????

 

[BrooklynBay]

Welcome to this forum! I've moved your thread into the stock 2006-2010 section. It's probably the radiator fan.

 

[waskly]

radiator fan clutch.

 

[jakesc7]

Welcome to this forum! I've moved your thread into the stock 2006-2010 section. It's probably the radiator fan.

Thanks guys. That seems to be the noise I'm hearing. I've also heard of issues with them in the past.

Why would it turn on like that w/ the a/c off?, could it just be a sensor?

Or will I need to replace the part?

 

[waskly]

your fan clutch could be normal operations or signs you might have low coolant.

 

[jakesc7]

Appreciate the info. i can see the large fan under the hood, i'm guessing thats where the fan clutch is located too...can you describe what it looks like so I take a look at it?

I have heard of many different solutions to this "loud" fan clutch. Could it really be a normal operation of the vehicle? The sound does go away, so its not locking up on me, which is good. I'm just worried that loud noise (when the a/c is OFF) is a warning sign that my vehicle is getting too hot.

I guess if the fan clutch looks good, I'll have to make sure the thermostats' working correctly, my next step is to get the cooling system flushed to make sure I dont have any leaks. If its none of the above, I guess it really is just the way the SUV was built. B/c getting a new radiator doesn't seem to help, fwih.

 

[waskly]

easy way is, if you have assigned parking or a drive way etc check under the car, or if you park in garage, put a piece of carboard under the vehicle does it get wet do you see stains etc. (just make sure you dont use the ac prior to this, ac will drip also)

then if its yes. you probably have a leak. coolant flush dont test leaks it just removes old and adds new.

few helpful stuff i noticed with these vehicles. is the overflow bottle full? alot of times the overflow bottle will work on these cars and when you have a leak it will be empty.

2nd to check is when the car is cold, open the radiator cap (push down and turn counter clockwise) is the radiator full.

if both the overflow and radiator is full, you probably have no leaks and the system is working correctly.

if its low probably a leak, going by year best bet is check the radiator from the fan clutch side, is it yellow... etc...

 

[jakesc7]

Actually, yes it does drip a little (coolant/water mix). The drip is a very small drip, makes a small puddle the size of baseball overnight, but I can see how it would be a problem over a few months.

Ive noticed the coolant level in the overflow reservoir does seem low, but it has stayed that way for a while.

So I have small leak, but it seems its not coming directly from the radiator (the radiator is located in the very front of the vehicle, in between the grill of the car and that large fan...right??) The leak looks to be coming from around the engine area, so maybe its a leaky hose?

 

[waskly]

check the housing where the upper radiator hose the top black hose goes into the engine. those have a tendency to leak also. it can be anything simple hose to a housing to a radiator. even a hose clamp that broke.

also check the bottom hose clamps, on the pump engine side and the radiator from under the vehicle.

if it never acted the way it is now, i would suspect something is wrong with coolant in the vehicle causing the fan to engage while normally same temp/time frame it would not.

few places offer cheap pressure testers like harbor freight and other stores. but if its a yellow puddle water like, i would say you have a leak with low coolant you will throw that fan on.

 

[jakesc7]

thanks for your help man...I will def check all those things you listed.