Pulley Squeak From AirCon Belt/Crank Pulley replaced/All tensioners/Belts Replac

[jangle]

My E53 Diesel has had the Crank Pulley replaced twice once with an OE part and now a BMW replacement part.

This seems to have resolve 80% of the strange engine squeak all I am left with is a squeak from the air con tensioner.

If I lube the tensioner the noise disappears however I replaced it this weekend and still the issue resides.

It is driving me crazy.

All the belts and tensioners have been replaced including the Air Con pump and still I have a squeak.,

Any ideas welcome.

Stuart

[kkx5]

Did you use bmw dealer oem belts?

[X5-D-Sport]

As a point of interest,
My E53 Diesel Facelift crank-pulley sheered at the doughnut centre rubber join recently.

It turns out that the crank end stub on this engine is a weak point and these ridiculous crank pulleys are a vibration damper to prevent the crank end fatiguing and snapping off !!

I also get a small squeak on start up & switch off where the belt squeaks momentarily due to the sudden stop jolt shock.

I think the tensioner is able to be set as a pre-load tension, where by it is spring loaded initially to set the tension, then locked to the block with a set bolt.

The OEM pulley is the one to go for, as the copy units WILL FAIL as I found out also.

Where possible go for OEM belts or a recognised brand of replacements, as the cheap ones stretch a little and create an acceleration & deceleration on every revolution of the engine causing the various pulleys to accelerate & decelerate also.
This change in rotation speed may only be minimal, bit it loads the crank pulley rubber centre bush & will cause it to keep failing, and the belt problem will become worse exponentially rapidly until either the pulley fails again or a belt fails.

Suggestion is...
Change ALL/Both THE BELTS asap, and re-tension tighter until the squeak stops.

Lubricating the pulley will simply splash lubricant to the belt surface & simply allow the belt to SILENTLY slip a while, until the lubrication buggers off .... meanwhile, the belt has heated up and got even slacker & more worn thru slippage.

Hope this helps.

[jangle]

Thank you for your assistance.

The belts have been replace 3 times by parts supplied and fitted by BMW.
They claimed the AirCon pump was at fault.

I removed the belt and everything sounded ok.

Replaced teh AirCon pump and the squeak returned. I sprayed the tensioner and the squak was gone.
I ordered a new tensioner made by Gate but was unable to get the rear screw removed so just replace the wheel as the other parts had already been replaced.

Seemed ok then started squeaking so checked the teeth and moved it over slightly and it appears to go.

24hrs Iran the car the next day it was a cold morning and squeak has returned.

So the next action is replace the belt please advise on preferred manufacturer or website?

It also appears the Air Con after gasing has a leak as it has stopped working

Stuart

[X5-D-Sport]

Im wondering if the AC pump is seizing up ? but you already swapped that out...

an easy way to work out where the initial issue is coming from....

Simply remove the little belt that turns the AC pump, the big belt will run ie alternator / pwr steering  / water pump.... and if that lot runs without issue, then it is narrowed down to the AC unit.

I heard that it is also conceivable that the AC pump can suffer a hydraulic lock... but may have miss-heard.

Meanwhile, omitting the little AC belt will keep you rolling safely ....

until some one here Like X5-Sport Richard throws his 3 penneth worth in - this guy knows his stuff and is either current/past BMW employed.

[X5Sport]

Never been employed by the 'Dark Side'.  Just an engineer with a high level detail interest in all things BMW - and who had way too much time

My E46 suffers the same issue with the same engine and I'venot been able to narrow it down.  It only does it at the moment of engine start.  The gas level is fine, the belt (though 10 years old now) appears fine too, and the compressor seems fine as the system works.

In my case it sounds like metal on metal but I can't find anything obvious.  It's also temperature sensitive.

Not sure about a hydraulic lock as the liquid should convert back to a gas.  I might be wrong but I thought the compressor was centrifugal and not piston based which makes a hydraulic lock very difficult.

[X5-D-Sport]

The power of the Dark side...

Richard... or should we now call you Yoda...lol..

Centrifugal pump.. indeed, there should be No hydraulic lock...

This one has me puzzled....
Maybe you two should natter with PM mails & see how to resolve this one ?

Meanwhile, Im wondering if he should omit the AC belt to keep rolling safely until a fix is discovered ?

[jangle]

The pump is spinning but I assume that unless the A/C is engaged then it's not engaged.

The other devices running on the other belt have all been services and they have no issue massive cost from BMW.

They replaced my rear sub frame bushes and left my with a whining noise which eventually turned out to be a broken prop shaft.

I am keen to resolve this last issue.

I have pulled the tensioner away live to see if the noise decreases and it appears to come from the tensioner on the A/C,. I am more than happy to replace the belt what would be a good choice.

I have noticed the AUX fan on a lot more than i  would expect but BMW said this is normal only started after they had had it for 1 month.  The temp gauge is fine and I have it running on waterless coolant.

thank you for you ideas and I hope we can resolve this as it is driving me mad, I have thrown so much time and money at this.  I really appreciate this car and want it to be perfect..

stuart

[X5Sport]

The Aux fan should run if the a/c is running and the clutch on the compressor should engage as long as enough gas is present.  The clutch will allow the pulley to freewheel if the a/c is not operating.  You should here a 'click' with the engine running when you turn the a/c on and off (snowflake button).

[X5-D-Sport]

Hi Stuart,

Very often the issues on these machines are actually SOOOOOOO simple..
it's a complex machine with many features...and nailing the cause is the tricky bit, cos there is so much to hunt thru.

Gotta say, I've been plagued with issues with mine, and I guess the previous owner simply ignored the little failures, but I want them all fixed, like you do.

eg, this air suspension set-up.... sounds scary, but actually it is very simple - just a case of understanding where all the bits are and how to resolve them... in reality, its a doddle & a very good system indeed.

[jangle]

The clutch on the A/C pump engages and works and the fan kicks in to cool the rad however.

With the A/C off I have noted the AUX fan kicking in assume the A/C is triggering it as the car temp is still normal, I wasn't sure if waterloos coolant can alter the temp sensor so replaced it..

Can the tensioner (back part) be configured to adjust the tension BMW say they have adjusted it an resolved the issue but no it is still there.

I am assuming I have a leak in the condensor for the A/C and plan to replace the same time I pully off the front bumper to replace the PDC sensors.

I had hoped to also upgrade the prefacelift Xeon head lights for Depo but unable to locate a UK supplier and I hear mixed reviews.

What is the best way to attack this?

Regards,
Stuart

[X5-D-Sport]

The fan that kicks in/out isn't for engine cooling, it is to chill the AC condenser/rad which is mounted forward of the engine cooling rad.
In theory the AC fan is temp & pressure sensing.
Rumour has it, that this fan is a variable speed unit too.

I'm in the dark on the AC fan, as the fan on my car has never bloody worked & I am trying to make it work, so I can stay cool in the summer traffic jams...

The engine cooling fan is the viscous fan on the front of the engine that runs all the time the engine turns.

With the AC snowflake switched OFF, the AC module should free-wheel.

The pulley on the AC unit it coupled to the main rotating pump stature by a crude clutch assembly.
When the button isn't illuminated, the pulley will free wheel, and the AC pump guts will remain stationary.
You should be able to see the difference between the stationary bits & the moving external pulley grooves...

If the whole lots keeps moving whether on or off, then some thing is wrong with either the switching, the sensing, or the pump clutch is jammed solid.

There should be zero engine drag from the AC unit when the clutch disengages.

For my money, I would remove the AC drive belt for now, so the vehicle will at least drive reliably... and in theory the damned squeak will stop !

You can check & spin the tensioner pulley wheel by hand, and the AC pump outer to see if it all free spins when the AC is turned off, the pump should also turn easily by hand also when engaged but with a little more resistance due to turning the pump vanes.

At least this way, you can find out exactly what is running tight....

[jangle]

Ok, I have success at last.

I have replaced the Air Con Pulley and belt and had the system evacuated and re gassed and now everything has settled down.

All I need to do now is understand why the AUX fan kicks in when the AirCon is switch off and the outside temp is 12c?

Stuart

[Steamyrotter]

Richard = Yoda...  Lol  love it  >:D

The AC fan can be configured to assist engine ASAIK, and i believe is programmable for towing pack..
and yes it is variable speed.

If you haven't got the AC fan then keep your engine revs up and the viscous fan should bring enough through to cool the condenser and then keep your tootsies cool???

[jangle]

Thank you Steamyrotter,

What call the AUX fan in when just ticking over, the water temp sensor.

Is there anyway to diag the process from what is calling the fan to what is turning it off.

I assume it's not the final stage resistor.

I am just worried the car is compensting for something the dealer may have broken during all teh work undertaken.

I have also replace the cool fluid for waterless fluid which prooved it weight in gold when the bleed nipple fractured by the over flow tank.

Any ideas or thoughts would be greatly received, BMW say I need a new fan.

Regards,
Stuart