Whirring sounds that comes and goes

B4WATERSKI

MEMBER
2008 DODGE AVENGER
90,000 MILES

After I start my (4cyl) avenger it starts making a whirring type of noise that comes and goes and varies in volume, sometimes while running everything sounds normal and then all of a sudden this whirring/grinding type of sound pops up, gets louder, gets softer, gets quiet, no pattern, just always changing. Turning the heat or a/c on doesn't change anything. The sound seems to be coming from the belt tensioner/ac compressor/power steering pump/alternator area but I can't be sure. I don't know if it might be one of the pulley bearings or what but it is the only car my wife and I have and therefore, cannot let it become undriveable. Please help :) Joel & Patty

6 Replies

HMAC300

MECHANIC
48,601 POSTS

This could be a couple of things, your car has what is called an adp pulleyon the alternator it can be that, the belt or tensioner. Spray water on belt if sound goes away then replace the belt and tensioner. Actually the belt and tensioner shold be replaced anyhow as they are recommended at 60K. Have a pro look at this because there are special tools required for the adp pulley to remove and install it.

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Saturday, November 2nd, 2013 AT 11:15 AM

B4WATERSKI

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4 POSTS

I tried putting water on the belt while it was running and it didn't seem to quiet things down at all. If I had to guess where the sound was most noticeable I would say it sounds like it might be originating from the power steering pump pulley. With the motor off I tried to move the power steering pulley with an in and out motion and it has a 1/16" - 1/8" play. Could is be the cause? Joel

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Saturday, November 2nd, 2013 AT 1:25 PM

HMAC300

MECHANIC
48,601 POSTS

I kind of doubt it but there are certain things to check with the belt off, like the tensioner pulley and alternator pulley. The p/s pump normally has en d play like that. Have a pro take a look at it.

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Saturday, November 2nd, 2013 AT 1:35 PM

B4WATERSKI

MEMBER
4 POSTS

Last night I replaced the belt, belt tensioner assembly and lower idler pulley, the upper pulley was nice and quiet so I left it alone. After doing these things I started it up and while the whirring noise decreased a bit it is still present. It seems to be coming from either the power steering pump or alternator. With the belt real loose I started the motor and the engine was nice and quiet so it seems like it is not anything internal on the engine. With the belt loose I spun the power steering pulley and it seemed ok but couldn't really spin the alternator pulley to see if it was ok. Are either of these things prone to noise problems? The car has about 90K miles.

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Sunday, November 3rd, 2013 AT 8:04 AM

HMAC300

MECHANIC
48,601 POSTS

With belt removed try to spin alternator pulley both ways if it does then the adp pulley is bad. It should only go one way. That willneed special tools to remove it and the correct pulley as well as there are several different ones.