Alternator squeal after engine start

[R.O.R-2.0]

to be honest you think the germans would have been smart enough to not use v belts and mechanical tensioners, they are the worst f**king  thing to ever use in a vehicle. ive gone through 3 belts this month. the only true way to get rid of this problem would be to either swap to serp or drop in an aaz. it just happened to me again tonight coming home from the drive in, if i dont sit there for 5 min untill my tach starts working, the belt snaps, u can smell burning rubber. so amazingly aggravating that it makes me want to put a brick on the pedal and run it off a cliff. it helps if the pullies line up, usually have to find a old alternator to find shims because they stopped including them with new alts.

Cold start of my Ecodiesel...

http://www.youtube.com/watch?v=ZHVXbKD5IPk

...No squeal.

Nice! Is adding the roller tensioner the only change? Did you keep the stock tensioner?

 there is no stock tensioner? just the pivot point of the alternator..

[larry104]

Yes, I use the stock tensioner with the additional idler.

to be honest you think the germans would have been smart enough to not use v belts and mechanical tensioners, they are the worst f**king  thing to ever use in a vehicle. ive gone through 3 belts this month. the only true way to get rid of this problem would be to either swap to serp or drop in an aaz. it just happened to me again tonight coming home from the drive in, if i dont sit there for 5 min untill my tach starts working, the belt snaps, u can smell burning rubber. so amazingly aggravating that it makes me want to put a brick on the pedal and run it off a cliff. it helps if the pullies line up, usually have to find a old alternator to find shims because they stopped including them with new alts.

Cold start of my Ecodiesel...

http://www.youtube.com/watch?v=ZHVXbKD5IPk

...No squeal.

Nice! Is adding the roller tensioner the only change? Did you keep the stock tensioner?

[92EcoDiesel Jetta]

Just picked up a Goodyear Gatorback 13276 V belt for the alternator. 13276= 13/32 width (10 mm), 27.6" (701 mm) length. Made in Mexico! Hope it's a good belt. I am going to try scuffing the pulleys and tensioning it and see it it stops squealing. If not, I'll try to add an additional idler tensioner. Jack, what did you use for an idler? Is it spring loaded or fixed?

[92EcoDiesel Jetta]

Cold start of my Ecodiesel...

http://www.youtube.com/watch?v=ZHVXbKD5IPk

...No squeal.

Hey Larry, I noticed at the end of the video the chime sounding. My doesn't work. Where is the chime located? I want to use it as an alarm for warnings.

[R.O.R-2.0]

Cold start of my Ecodiesel...

http://www.youtube.com/watch?v=ZHVXbKD5IPk

...No squeal.

Hey Larry, I noticed at the end of the video the chime sounding. My doesn't work. Where is the chime located? I want to use it as an alarm for warnings.

someone probably pulled the door chime relay.. most VWs are that way. its not a required piece to the car, just annoying..

[92EcoDiesel Jetta]

I was alerted to the fact that as the belt tension is adjusted more and more, the belt contact area to the alt pulley becomes less and less, making it more prone to squeal. With that in mind, I think the place to put the idler is where the OEM tensioner is located. Basically ditch the OEM tensioner and put an idler there to push the flat part of the belt inward (rather than outward), thus giving the belt more contact to the pulley as you tension it more. 

[larry104]

I was alerted to the fact that as the belt tension is adjusted more and more, the belt contact area to the alt pulley becomes less and less, making it more prone to squeal. With that in mind, I think the place to put the idler is where the OEM tensioner is located. Basically ditch the OEM tensioner and put an idler there to push the flat part of the belt inward (rather than outward), thus giving the belt more contact to the pulley as you tension it more.  

Tried that; It doesn't work. The arrangement significantly back bends the belt so it goes through a large stress reversal each rev, leading to early failure. In my setup, the extra idler maintains an adequate wrap angle without excessive back bending. In practice, I tighten the OEM tensioner to slightly less than than full tension. Then I bring in the extra idler to re-establish the wrap angle and properly tension the belt. It's important to mostly tension the belt with the OEM unit. This way, the extra idler barely back bends the belt.

[92EcoDiesel Jetta]

The new Goodyear belt I put on lasted 3 weeks before it stretched to the point where there are no more adjustments with the tensioner. I put on a lawnmower belt, a Gates 6827 to be exact and so far so good, no squeal even with glow plugs, head lights, and blower on!. It remains to be seen how long it will last. This belt is wider (1/2" wide) and is meant to drive a higher HP load with a stronger grip. It has no teeth for cooling so may run hotter. We shall see how long it will last. If it works out well, I may change the rest of the belts to the 1/2" lawn mower belts..

[wdkingery]

How is your alternator spinnin with the glow plugs on at the same time?
Or did I read that wrong?

[92EcoDiesel Jetta]

How is your alternator spinnin with the glow plugs on at the same time?
Or did I read that wrong?

I have a rocker switch to turn the glow plugs on or off anytime I want. The glow LED as well as a chime is wired in parallel with the glow plugs so I can see and hear when they are on so I do not forget that they are on.

[R.O.R-2.0]

The new Goodyear belt I put on lasted 3 weeks before it stretched to the point where there are no more adjustments with the tensioner. I put on a lawnmower belt, a Gates 6827 to be exact and so far so good, no squeal even with glow plugs, head lights, and blower on!. It remains to be seen how long it will last. This belt is wider (1/2" wide) and is meant to drive a higher HP load with a stronger grip. It has no teeth for cooling so may run hotter. We shall see how long it will last. If it works out well, I may change the rest of the belts to the 1/2" lawn mower belts..

there is a difference in the angle of the V-groove on metric, and SAE pullies..

using a SAE belt on Metric pulleys will not result in a long lasting belt.

[92EcoDiesel Jetta]

I was alerted to the fact that as the belt tension is adjusted more and more, the belt contact area to the alt pulley becomes less and less, making it more prone to squeal. With that in mind, I think the place to put the idler is where the OEM tensioner is located. Basically ditch the OEM tensioner and put an idler there to push the flat part of the belt inward (rather than outward), thus giving the belt more contact to the pulley as you tension it more.  

Tried that; It doesn't work. The arrangement significantly back bends the belt so it goes through a large stress reversal each rev, leading to early failure. In my setup, the extra idler maintains an adequate wrap angle without excessive back bending. In practice, I tighten the OEM tensioner to slightly less than than full tension. Then I bring in the extra idler to re-establish the wrap angle and properly tension the belt. It's important to mostly tension the belt with the OEM unit. This way, the extra idler barely back bends the belt.

FYI. I learned (from talking to engineers at belt manufacturers) that automotive V-belts are not designed to have a roller pressed against the flat part of the belt as you are doing, whereas the lawnmower belts are. If you have no problems, then great. If you do, you may want to consider going to a lawnmower belt.

[92EcoDiesel Jetta]

The new Goodyear belt I put on lasted 3 weeks before it stretched to the point where there are no more adjustments with the tensioner. I put on a lawnmower belt, a Gates 6827 to be exact and so far so good, no squeal even with glow plugs, head lights, and blower on!. It remains to be seen how long it will last. This belt is wider (1/2" wide) and is meant to drive a higher HP load with a stronger grip. It has no teeth for cooling so may run hotter. We shall see how long it will last. If it works out well, I may change the rest of the belts to the 1/2" lawn mower belts..

there is a difference in the angle of the V-groove on metric, and SAE pullies..

using a SAE belt on Metric pulleys will not result in a long lasting belt.

Accoring to the Goodyear engineer I talked to, their automotive V belt in the size for my 92 VW jetta is 37 degrees, metric or SAE. Do you have any info on what angle the Metric belt should be? All I know is the Lawnmower belt I am using is not squealing with the heaviest load I can place on the alternator, so it must be making better contact than all the previous belts I've used, one of which was a Continental metric belt and they all squealed and stretched till there is no more adjustment on the tensioner.

[burn_your_money]

You guys should try doing a voltage drop test
http://www.vwdiesel.net/forum/index.php?topic=22321.0

I don't ever recall having problems with my belts other than when I don't tighten them for months and then go through a deep puddle.

[92EcoDiesel Jetta]

My guess is you have no AC or the AC compressor was removed?

You guys should try doing a voltage drop test
http://www.vwdiesel.net/forum/index.php?topic=22321.0

I don't ever recall having problems with my belts other than when I don't tighten them for months and then go through a deep puddle.