I've had a couple of occasions where my rad fan (I'm guessing at this) makes a really loud droning sound that can actually be 'felt' in the car.
It doesn't always do it - in fact, it's done it twice in 2 weeks.
I think it's the fan as it only happens after I've been driving a while, and today it continued about 30 secs. after the car was turned off.
I didn't get a chance to peer under the bonnet (hood) as it raining like the clappers.
Anyone else had this?
Is it a new fan needed or is it fixable???
Roy.

 

you need to change the thermostat NOW..the fans are easy to replace so is the stat.

 

+1

Sounds like it's overheating.

The fans can continue to run after the car is stopped during our Summer but I doubt it's been anywhere near warm enough air temperatures in Ipswich today for that.

The fans should also run very quietly. You'll hear the air movement but there should be no transmitted vibration. Check the fan cowl fixings and fan motor bearings.

Graham

 

Exact same thing just happened to me. I have purchased a new Thermostat and will install it tomorrow.

 

The new thermostat may be warrented due to your description of the fans runnning on after switching off the engine. Mine do it also from time to time, so I too will seriously consider a new thermostat added to my to-do list. However, that won't cure your noisy fan. You might try a squirt of your favorite lube into the fan bearings just to see if it stays away longer - but being intermittent in nature as you describe, you may not see results. Wouldn't be a permanent fix, but if even if it temporarily goes away you can figure you have identified the problem.

For the life of me I can't figure out what else might cause the symptoms you describe, so definitely follow up on Graham's suggestion of checking the surrounding fixings too. Even a small vibration will get amplified depending on what it's acting upon.

Steve

 

When my Fans were running they were Very Loud. I have never heard them make that much noise in the past.

Upon investigation, the Electrical Diagram indicates that Both Radiator Fans run at the same time.

However, the ECM controls them and can run them in 2 modes, Series or Parallel. As configured, the ECM can not turn on just One Fan.

They are NOT Pulse Width Modulated. The only Modes are:
1) Off.
2) Low Speed on BOTH Fans. (6 volts on each Fan).
3) High Speed on BOTH Fans. (12 volts on each Fan).

In the past, I believe that they were only called on to run in the Very Quiet Series mode (Mode 2 above).

Depending upon the Coolant Temperature Input to the ECM, they may be called on to run in the Very Loud Parallel Mode (Mode 3 above).

Both my Fans turn freely and the Bearings turn Smoothly.

The Parallel Connection will cause both fans to run at a Much higher Speed (Mode 3 above) with attendant Vibration.

 

Didn't know there were two modes. Very interesting! Thanks,

Steve

 

Update: Bought new Thermostat at Advance Auto Parts. Stant #14748 183 Deg F, $12.99

This is EXACTLY the same as the OEM unit that I found in the car.

Before installing the new unit in the car, I put them both in a pan of Boiling Water. The new unit opened shortly but the old unit did NOT open.

Installed New Unit in Car, went for Test Drive and all is well.

When the old unit was failing, the (Infamous) Temp Gauge did not indicate High Temp.

So, if your Radiator Fans start to run at High Speed after Engine Turn off, REPLACE THE THERMOSTAT!