Belt squeals

[v8volvo]

Originally Posted by 745 TurboGreasel

The blower motor is also probably against you, it's a huge current draw, and since they are mounted in such a way as to water the bearing, in 740's they are never in good shape(at least they are easy to change).

+1, want to watch out for too much noise or draw from these as they are also notorious for melting the fusebox when they pull too much current, esp if the connection at the fuse is iffy. 35A is too much; I have wondered about putting in a 25A fuse because it melts the box before the fuse blows. The alt is 55A; think about using all of that fuse's capacity, it's well over half the total alternator output....

[Fridgewagon]

^lulz.

The big problem is the cowl drains getting all clogged up as well as the blower box drain. If they aren't all gooped up, they work reasonably reliably on 700s. Usually you really have to blow them out carefully. All the detritus in there also holds moisture, which greatly increases the humidity generally, which usually makes for squeaking, corroding fan motor moving parts.

Theoretically, maximum alternator output is 55A, at minimum full output RPM...like 1800+ (engine, not alternator) RPM, if no belts slip, with the right phase of the moon with brand new perfect wiring on a brand new car

2 or 7 series the belt wrap isn't excellent for the fan or Alt, accessory bushing dealies are often all dried up worn out junk, and at least with the gas Volvos, the Roulands or "Volvo" (I suspect the same) are 9.5mm width with the correct taper and actually grip the belt pulleys properly. The 10mm contis don't quite grab properly.

Theoretically, the accessory bushings extend belt or accessory bearing life, when they aren't all dried up junk, though one would imagine that unless on a cool weather car with zero oil leaks with them changed out or flipped position every other belt chang, more often than not they have the opposite effect.

Many modern diesel engines have a power pulsation/vibration dampener on the alternator pulley itself, which is quite logical; large reflected moment of inertia on the alt (or fan, but alt especially), with a heavy rotor and ~4:1 pulley size ratio, diesel engine with strong compression/power pulsations on long stroke heavy engines. Of course, these are largely to improve belt/other accessory part life. Of course, more often than not, the pulse dampener itself prone to failure. Usually they are a sort of rubbery/ratchet contraption, which has a small space in which to live within the alt pulley. Has a profound effect on how smoothly the belt(s) run when it actually works.

Benz solves this problem on later engines with a shock absorber and heavy tensioner. Expensive part when it wears out, not rebuildable on later ones, but often lasts the longest.

Volvo stuffed the already undersized accessory bushing dealies on the diesel with less than great belt wrap or bracketry...
...not to mention finding the correct # belts through the dealer or set of correct roulands for the diesels was always a PITA. I'm not looking forward to this.

[745 TurboGreasel]

Originally Posted by v8volvo

Interesting but I guess kinda not surprising to know how much of the juice goes to accessories vs driving -- I assume this was calculated over time for in-town driving? At low speeds, with not much wind/road resistance and plenty of regen braking, the numbers make some sense, even as odd as they are....

It has a pretty versatile onboard energy display monitor.

[RedArrow]

Originally Posted by v8volvo

Getting it tight and keeping it that way takes some tricks...

Great stuff. Will follow this method and do it your way. What`s the torque specifications on the bolt that goes through our oil pump housing?
I cant have my gasket messed up .

[jpliddy]

hi i tried a gates belt but it did not last long . the genuine belts are better build and slightly thicker dimensions only very slightly . but alternator belts don't seem to last long enough on my engine .20000 miles max before signs of wear as in photo . i think other things are wearing a bit in this area now but with 222000 miles now .so hope the gates belt serves you better than mine . keep us informed of progress.

[RedArrow]

Originally Posted by jpliddy

hi i tried a gates belt but it did not last long . the genuine belts are better build and slightly thicker dimensions only very slightly . but alternator belts don't seem to last long enough on my engine

You are right about the Volvo belt because I`ve been torturing this oem belt for such a `long` time, not caring much that it already showed signs of wear 2+ years ago! I did care but was always hesitant to mess with the alternator. Had to tighten it a few times before... I did not use the right method but the belt itself held up nicely and never broke (yet). It even survived the fact that it was slightly misaligned (thanks to bad ps bushings) for at least 6months.

Wondering if a pulley with surface rust could be pushing yours towards the regular premature death. Mine also has some minor surface rust on the pulley but will confirm this after the belt comes off. Is there a suggested treatment for when this happens to be the case?
Chemical removal or gentle sandpapering? idk

[RedArrow]

Well, I had a chance to sneak out of work, so....
the new Gates XL 7300 belt is on. Using the suggested method, I think I got everything set correctly, taking special care not to over-torque the bolt that runs into the block. It was easy to spot&use that square-shaped `nipple` on the engine block in order to stay safe with the heavy duty flat pry bar. (The aluminum housing looks fragile and the lower rad hose is relatively close too.)
It worked nicely.
Result is better than with my previous tightening(s). The belt squeal is gone. Time will tell if Gates is great or not; but it IS better than this bad condition oem belt I had on. omg.

The fluctuation of the Volt-gauge is not yet gone though (mostly caused by the heater/blower being ON. I started hearing a stupid crap noise from somewhere behind the glovebox area. Kind of hissing I think. Not sure what it is...long ago it was heard Only when blower was set to windshield position... but now i hear it in All positions. Even when the big knob is turned into 0 (zero). Sounds like it`s still blowing air/heat or there must be something going on. (next project) It`s stressing me out and I truly hate it. (At least the heater works, blows hot air nicely.)

The polished surface of the pulley shows where the old belt ran. Because now the new (wider) belt just can`t sit all the way down in the deep grove, it actually runs on the rusty area that the crappy belt wasn`t touching at all, for long years. I did not clean the rust off, let`s see what happens.

The Gates belt actually runs `on the top portion` of the pulley. My pictures well illustrate this concern. The Volvo belt ran differently than the new one. I`ll keep my eyeballs on it, surely I will have to retighten the new belt in the future.
For now, the `top` of the new belt sits literally `higher` than the edges of the pulley. As belt wears, it should sink down...? (New belt looks finely seated on the bigger pulley. That pic shows the worn Conti steering belt, also the ac belt missing)

[RedArrow]

Inside and outside, toast.

[745 TurboGreasel]

That belt was done for before it sunk to the bottom of the V.
All is well.

Don't be surprised if you check tension in a week or so and have to tighten it a bit, they usually stretch a bit in the beginning.


Re.noise
if its air in the vac pipes;
Vac supply for the whole climate cluster comes in the right side of the dash i think. if none of the vent doors work and you have no temp control(with the non computer system at least) it's probably that line. On the other hand, if one of the air motors has ruptured, there should be a way to keep it from getting signal.

blower motor noise;
Its always on a little to keep the bearing form seizing if you don't use it for awhile. simple test, reach up in the passenger footwell and unplug it.