Fan belt squeal...diagnosis? (too loose, too tight, etc.?)

[Guest Anonymous]

I actually drove Hugo yesterday for the first time ever!!! Needs to be aligned, but didn't drive too bad. He will need some suspension work eventually too, but at least he "drives"! I did notice a squeal however coming intermittently from the alternator drive belt though. I can't remember when there's a squeal in the belt if it's too tight, too loose, or the alt is misaligned.

Any advice, experiences?

Thanks,

John

'72tii "Hugo"

[Guest Anonymous]

Must be nice.

Too tight will hurt your alt bearings and it's mount, but shouldn't squeal.

Too loose will squeal, as will the wrong belt. Apparently the angle of the pulley's V is different for BMW than anybody else, so the wrong belt doesn't get much contact.

If your alt mounts are crappy it could make it hard to get the tension right.

[Guest Anonymous]

Squeal is too loose, but also make sure pulley alignment is correst. The original type rubber bushings on a bosch alternator have a limited life and then they colapse to one side making the belt misalign. I recently upgraded to the urethane alt. bushings and corrected this permanently. DO NOT overtighten the belt as it will cause premature waterpump bearing failure.

[Guest Anonymous]

(nt)

[Guest Anonymous]

I'm experiencing a similar problem with my 72Tii, and I know its the mounting hole that has gone out of round. Is there a way to fix other than replacing?

[Guest Anonymous]

(nt)

[Guest Anonymous]

replace the belt. They can glaze over eventually, and cannot grip the pulleys properly.

[Guest Anonymous]

Just my expierience, but I had a squeaky belt before, and I tried everything, different belt (not oem), spray on sticky stuff, and everything in between. Finally I was told to use a oem belt, which fit the pulley, because of the contour, the aftermarket belts had a "one cut fit all".

Well I took the advice and had no problems since, on a daily driver.

[Guest Anonymous]

I had a new alt, factory bushings, factory belt. Had a hell of time with it until I replaced the rubber bushings and now, all ok

[Guest Anonymous]

"This state is too cold in winter; I need to be sent to Puerto Rico so Victor, Harry and Pablo can take care of me!!" ;-P

Sorry, couldn't resist ... that tii of yours is soooo nice I'm drooling!

Victor

Well, if you decide not to send Hugo down to PR, by all means think of an excuse and get yourself down here!! (Summer isn't over you know!)

Nice job on Hugo!

[Guest Anonymous]

Wallothnesch carries them but so does Carl Nelson, 10 x 975 for the tii I believe. These are the oem fan belts.

Tim

'69 2000

[Guest Anonymous]

URL: http://www.jennaishealed.org/

squeal is always loose. you should be able to tell tightness without starting it. deflection between the pulleys (fan and alty) should be around a half inch tops. or you can do it "by ear": tighten until it stops squealing (with highbeams and heater fan on, etc)

-Rob

-Rob

[Guest Anonymous]

(nt)

[Guest Anonymous]

belt reference book seems to catalog the same belt for the car. Problem is that if the belt rides too deep in the pulley V, it'll stretch, then overheat and fail within a few thousand miles. If the belt's too wide, it'll ride too high in the pulley, make poor contact and squeal. V-belts grip on the sides, not the bottom, so you want the belt's top riding just at the pulley's rim.

And yeah, it's usually bad alternator mount bushings. Use urethane.

Cheers & congrats on Hugo's first voyage

Mike

[Guest Anonymous]

second the loose belt. Becomes more critical when substituting the

rubber.

I still think the alternator should be driven from a pulley on the drivline

under the seat somewhere with an idler bearing. More wieght aft.

closer to battery in trunk etc. But that is just me.

good luck

John McA