Alternator Belt Whining Like A Mother Fu...

[240meowth]

Behold, this has been plaguing me for sometimes.

I'm running them CA18DET things, and the alternator whines super loud on start, or when i turn on my headlights. I've replaced the belt, tightened it to the max, and it is still whining.

I've tried belt dressing, and it is fixed for like a day, then it whines again.

I've tried silicone, and it whines worse.

So i figure, maybe there's too much shit on the pulley. So today I took the belt off, and sprayed the alternator/water pump/crank pulley with brake cleaner until the whole can is used up. Put everything back. Still whining.

One thing I noticed: i have an apexi auto timer which tells me the voltage of the car, if the voltage reaches 12.6v it stops. But when I just start the car it sometimes is at 11.8v and climbs up and whines all the way, and sometimes it just hangs out at 12.3v no matter how much I rev the engine. I suspect, bad ground? So I added an extra ground wire from the battery, now I have one going to the chassis and one going directly to the engine block.

Bat battery? I notice that it's at 12.5v ish all the time, shouldn't the voltage be more at 14v when the car is turned on? I took the battery back for testing and they said it's good.

So today I ran the car w/o battery, still at 12.5v ish. Is this... all a symptom of a bad alternator? I am confused as hell, hence I've surrendered to zilvia.

[Def]

Definitely sounds like a slipping belt. Does it stop at higher RPM (usually this happens because the torque on the belt lessens for the same power transfer)?

It's possible the alternator pulley is worn, so it really isn't putting force on the grooves properly. Dayco actually makes a belt specifically for this, with W shaped grooves instead of V shaped ones.


You also don't have any oil leaks or anything like that do you?

[StryfeS13]

It is possible that the long bolt that holds the alternator to the bracket does not have a nut on the back of it. So what would happen is even if you adjusted the tensioner, in time it'd fall back down because it's not secured tightly to the bracket..

try to check that out

[Sileighty_85]

belt dressing is garbage, it just glazes the belt over time.
Silicone? that probably the worst thing you can put on it.

replace the belt, maybe with a differnet brand?

[codyace]

Check the pullies for any sort of of glazing or polished look to them. I know it may take some time, but some emory cloth (folded) and some persisttance you can clean/roughen up the pulley grooves to help reduce the noise. Another option is to simply take the pulley off, and media/sand blast the grooves.

[240meowth]

problem solved! Turned out the belt I got was wrong, it was 4pk865 when i'm suppose to use 4pk855. I went to the shop and asked for the belt for ca18de from 88 nissan pulsar SE and they gave me something strange. so i asked for 4pk855 and they only had 4pk840. worked like a charm.