Annoying noise when cooling fans are running

[smith281]

Hi all,

Another problem I'm hoping you can help me with (it's one thing after the other with an old car!!):

On my 4.5l petrol Troll, there is a whining noise whenever the electric cooling fans are running. The two electric cooling fans in front of the radiator switch on and off when the engine is idling. I'm assuming there is a temperature switch somewhere which turns them on and off.

The whining/rattling noise is quite annoying and I can't seem to find where it's coming from. As the noise is only there when the fans are running, I initially assumed that it was one of the fans making the noise. But i've tried disconnecting both the fans and it doesn't affect the whining noise at all.

The noise sounds a bit like a warn out bearing. The noise changes pitch with the engine revs.

Any advice on where to start looking!? When the cooling fans switch on and off, is there something else turning on and off? Is there any link with the AC compressor?

Cheers,
Tom

[the evil twin]

I know sweet bugger all about 4.5 Trol's, didn't even know they had twin thermo's, so I assume they are factory and this is a shot in the dark.

I don't quite get " As the noise is only there when the fans are running, I initially assumed that it was one of the fans making the noise. But i've tried disconnecting both the fans and it doesn't affect the whining noise at all"

How can the noise only be there when they are running and if they are disconnected

Obviously, it isn't the fans if the noise is still there when the are disconnected. Soooo... In most twin eleccy fan setups both are actuated by engine coolant temp and only one by the Aircon. The Aircon controlled fan should kick in with the A/C Compressor so maybe one is masking the other?

[wildgu6]

Same prob' with my GU and it has me buggered as well, will watch this thread with interest. Good luck

[BillsGU]

Sounds like the aircon compressor to me. Turn the radio up a bit !!!

[YNOT]

Sounds like the aircon compressor to me. Turn the radio up a bit !!!

I agree, sounds like a A/C compressor fault. Switch the A/C off and see if that stops the noise.

Tony

[wildgu6]

Sounds like the aircon compressor to me. Turn the radio up a bit !!!

LOL yep that's what I do already, but only hides the prob'

[Robo]

Older worn pulleys can make a noise, try a little silicon spray with engine off, as fan will just blow it everywhere.
You may find it takes couple attempts to cover.
not a heavy coat, just to aid belts movement.
I have found this works for squeaky belts, but washes off in the rain, and noise returns.
If noise goes then that's your problem.
Could be alternator bearings.
Idler bearings.
Even had a noisy air con clutch bearing.
Does the 4.5 have rubber type timing belt, I've had 1 of these belts make squeaky noise, they also have idler bearing.
Hope this helps

[YNOT]

Older worn pulleys can make a noise, try a little silicon spray with engine off, as fan will just blow it everywhere.
You may find it takes couple attempts to cover.
not a heavy coat, just to aid belts movement.
I have found this works for squeaky belts, but washes off in the rain, and noise returns.
If noise goes then that's your problem.
Could be alternator bearings.
Idler bearings.
Even had a noisy air con clutch bearing.
Does the 4.5 have rubber type timing belt, I've had 1 of these belts make squeaky noise, they also have idler bearing. Hope this helps

No, timing chain. RD28 was the only GU engine to have a timing belt.

Tony

[Cowboy]

Sound like pully's or the belts.
I carry a 1/4 cake of sunlight soap with me and rub that on the belts when running if the squeaks and rumbles happen. Check to see if the fans are "loose" by rotating both forward and backwards, if so, then bearings in them are worn, so a touch of machine oil (good quality) and only a touch is needed
Cheers

[wildgu6]

Well sorted my noise, definitely the AC unit. Sitting at lights and noise turned to a squeal like dry bearings ?and started smoking. (belt). Got home and removed AC belt and noise gone. Trol even runs smoother now. No AC but got windows...lol

[rusty_nail]

Well sorted my noise, definitely the AC unit. Sitting at lights and noise turned to a squeal like dry bearings ?and started smoking. (belt). Got home and removed AC belt and noise gone. Trol even runs smoother now. No AC but got windows...lol

you might find that the belt was the second thing to go, the noise was probably coming from the idle pulley attached to your A/C unit, the belt only started smoking up when the pulley couldnt keep up with the belt? just a suggestion anyway

[wildgu6]

you might find that the belt was the second thing to go, the noise was probably coming from the idle pulley attached to your A/C unit, the belt only started smoking up when the pulley couldnt keep up with the belt? just a suggestion anyway

Cheers buddy,Will check it out but seems to be quite free spinning without belt on. Think the old AC has had one to many dunkings.

[rusty_nail]

Cheers buddy,Will check it out but seems to be quite free spinning without belt on. Think the old AC has had one to many dunkings.

haha yeah poss, or at least all that mud and muck has gotten into those pulley bearings and f'd it lol