Testing a Fan Clutch

[ad244]

Im storing a family members 2003 Infiniti G35 with relatively low miles for the year at around 80,000 miles. Its a nice car and drives really well and has always been very well maintained. However, since ive had it for a few days, I noticed at low speeds the mechanical fan appears to be always engaged. From my many years owning chevys, this typically means the fan clutch is bad and needs to be replaced. From a stop to around 30+mph the mechanical fan is very much audible and sounds like a jet airliner taking off on its way to the moon.

Is there a good way to test the fan without getting my fingers chopped off? Or are these cars just typically loud?

Thank you

 

[kschachn]

IIRC the Haynes manual for my old BMW stated to hold it with a rolled-up newspaper.

 

[ad244]

IIRC the Haynes manual for my old BMW stated to hold it with a rolled-up newspaper.

Thats exactly what I have heard as well but I didn't want to sound like an idiot. Haha!

Again, Chevy world.

 

[kschachn]

It's been a few years but that may have been a test for one that was stuck "off" rather than on. Mine was like yours, it roared all the time even when the weather was cold. I just went and replaced it and that fixed the issue.

Here is an old thread on this subject and I see that I responded at the time:

fan clutch diagnosis

I drove my wife's Sequoia yesterday and am wondering about the "roar" coming from the engine bay. The 4.7 liter always makes this roaring noise on initial cold start-up which I am assuming is normal. It lasts maybe 15 or 20 seconds and goes away. However, yesterday we were running a little late...

bobistheoilguy.com

 

[Kawiguy454]

I beleive the failure modes for thermostatic clutch fans was typically that they either SLIP too much and overheat or the bearings go bad and they wobble. With engine off check for loose bearings and that the clutch has some resistance to turning when hot.

yours sounds normal to me as at idle or low speed with the AC on it needs a lot of airflow without benefit of forward movement. As speed increases the forced airflow cools the tstat and the fan slips more.

Reminds me of the old fords with the gigantic fan and shroud ...also very loud at idle.

 

[ad244]

I beleive the failure modes for thermostatic clutch fans was typically that they either SLIP too much and overheat or the bearings go bad and they wobble. With engine off check for loose bearings and that the clutch has some resistance to turning when hot.

yours sounds normal to me as at idle or low speed with the AC on it needs a lot of airflow without benefit of forward movement. As speed increases the forced airflow cools the tstat and the fan slips more.

Reminds me of the old fords with the gigantic fan and shroud ...also very loud at idle.

The vehicle was shipped out to me in Phoenix from Virgina and ill admit that it hasn't likely fared our 105 degree heat before. I'll look into testing it before just replacing the clutch. Access at least seems pretty easy.

 

[andyd]

The roaring fan is a locked up fan clutch. If you're gonna have a FC fail, that's the one you want. Coming back from Cooperstown in 3rd '88 528e , I noticed the roar and pulled into a rest area and removed it in a minute with the pliers in the toolkit. The fan is secured to the pump with a LH thread nut, You need to spin the fan on and only tighten it hand tight to keep it on.