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The mkiv Supra Owners Club

Loud whinning noise


dilocruzy

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When i start the car with the air con on, there is a terrible loud whinning noise from the engine, if i switch it off (air con, even without turning off the fan) it disapears:

 

Is there a separate belt for the air con compressor?

 

Could that be the problem?

 

Would this be a toyota part or a car air con specialist could sort out?

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screeching noise sounds more like it, its got 80K, and the noise goes away when i rev it up, or when its idle, the acceleration makes the noise, specially when on neutral (automatic car)

 

Thanks guys, really apreciate any help as I am in Portugal on holiday and the closest help is over 1000 miles away!

 

Dan

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Agreed jake.

 

If you start the car, turn the AC on, and then open the bonnet. Go around to the front of the car and look down at the bottom pulley. Give the engine a rev, whilst looking down. I expect you'll see the bottom pulley have a wobble. If this is the case then you'll need to replace the crank pulley.

IN GBP the pulley and the bolt cost about £200 inclusive of tax.

You should be able to find the part numbers on here if you do a search.

 

Hope that helps! :thumbs:

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Dilocruzy,

Do not attempt to drive the car further than strictly necessary if the pulley has sheared. If the outer ring comes off the inner one it could get very expensive.

I've got a spare low mileage pulley if you're desperate but I was planning on keeping it as a spare one for myself.

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Thanks for the help guys, if i dont switch on the air con, would that be ok to drive?

 

Many thanks, dan

 

NO!

 

First of all find out if it is the pulley. Some pictures here http://www.mkivsupra.net/vbb/showthread.php?t=41040&highlight=crank+pulley

 

If it is, then it could go flying up through the bonnet, through the fan (as has happened to someone) or anything..

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Thanks for the advice! and for your thread.

Did it also make the screetch when on idle and with air con off?

 

still got to get back home so ill have to try my luck...

 

 

 

NO!

 

First of all find out if it is the pulley. Some pictures here http://www.mkivsupra.net/vbb/showthread.php?t=41040&highlight=crank+pulley

 

If it is, then it could go flying up through the bonnet, through the fan (as has happened to someone) or anything..

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Ill try that and see if it works, I HOPE YOU ARE RIGHT!!!!!

Can anyone explain why this only happens when the air con is switched on?

 

Surely it could just be the fan belt slipping though? Try spraying some WD40 on the belt and see if the noise goes for a few seconds.
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Ill try that and see if it works, I HOPE YOU ARE RIGHT!!!!!

Can anyone explain why this only happens when the air con is switched on?

 

it could be one of two things, in my (uneducated) eyes:

 

1. It's RPM dependant. So even with aircon off, if you raise the rpm a little, it still does it.

 

2. The above is wrong. In which case your AC compressor has siezed or nearly siezed and so when the clutch engages, it is seizing the outer pulley so that the belt is slipping around it.

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Can anyone explain why this only happens when the air con is switched on?
The inside bit of your crank pulley is now seperate from the outer ring but the rubber that is supposed to hold them together is still providing some friction between the two parts. That friction is just about enough to rotate the outer ring of the crank pulley. However, when your AC is turned on there is more resistance so it requires more power to drive the belt around and this exceeds the friction between the two parts of the broken pulley, causing the seperate inner part to slip against the the outer part and make that squealing noise.
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Unfortunately I think this could be it, I hope the car will make it back to England, obviously no aircon for the trip...

 

Many thanks!

 

The inside bit of your crank pulley is now seperate from the outer ring but the rubber that is supposed to hold them together is still providing some friction between the two parts. That friction is just about enough to rotate the outer ring of the crank pulley. However, when your AC is turned on there is more resistance so it requires more power to drive the belt around and this exceeds the friction between the two parts of the broken pulley, causing the seperate inner part to slip against the the outer part and make that squealing noise.
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Yep, the belt has a few small cracks but nothing that hasent been there for a long time now, tried switching on the air con and looking at the bottom pulley as you mentioned, but no vibration seen, still wanna try the WD40 on the belt.

 

Have you looked under the bonnet yet?
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I was looking at my air con pulley yesterday; is it right that it only turns when the compressor kicks in;
No

mine is like that ie it doesnt move??

:conf: Is that a question? If not, then you are mistaken Richard. The pulley always goes around when the belt is going around. I think you might be looking at the static centre and ignoring the pulley itself.
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Yeah Jake, the centre is obviously moving or it would make a hell of a row, sorry my dumb question must get my eyes checked. :rolleyes:

 

No mate the centre is on a clutch. When the aircon is turned off, the centre is disengaged from the pulley itself. When the aircon is turned on, this clutch engages and the centre starts turning with the pulley (the outside bit), therefore driving the compressor.

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