Hi Everyone, I just purchased a 1997 Sebring convertible with the V6 engine, and I wanted to ask a question about engine noise.

When the engine is idling, there is a soft whirring noise that can be heard. This noise seems to be coming from the far left side of the engine when you are facing the car, the area by the serpentine belt. This noise becomes much louder when the engine accelerates. It quiets down again when cruising at a constant speed (say 55 mph). I thought that it was probably a bad bearing in the alternator or the idler pulley, but I have not had a chance yet to investigate further. I was also reading something on the internet earlier today which made me think that it might also be an issue with the timing chains, which are in the same area.

Any thoughts on what the source might be? Anyone heard of something like this before? Thanks in advance for your help.

Bill.

 

My suggestion would be some very careful listening while the car is raised so you can get under it if necessary. Please use jackstands or drive-on ramps. There are a number of items in that vicinity that could be causing that sound and not all of them are mechanical. It could be a vacuum leak as well.

In any case, the 97 2.5L V6 uses a timing belt, not chain. There is an inspection access towards the front of the engine at the passenger's end. Service / replacement interval on this belt is 105,000 miles. It's also the only way to get to the water pump so if you find it necessary to replace the timing belt, consider the water pump regardless of current condition to keep from having to go back in soon.

 

Bandaide,

Thanks a lot for the great suggestions. I picked up a cheap mechanics stethoscope last week, and went looking for the source of the sound on Saturday. It definitely seems to be coming from the serpenting belt idler pulley. There seemed to be some noise coming from the alternator as well, but I think that this was just vibrations from the idler that were transferred to the alternator via the serpentine belt. I ordered a new pulley, and should be able to pick it up tonight. I'll report back once the pulley is installed.

The information on the timing belt is good to know, since it probably has never been changed. If I decide to change it, I will definitely change the water pump at the same time.

Bill.

 

Automotive stethescope. One of the handiest and most overlooked tools.

The alternator will have a tendency to "whirr" because of the way it is constructed with the stator "lobes" acting like a fan. While you've got the belt off changing the pulley, you might want to spin the alternator by hand while doing some more of that careful listening. I did just exactly that on my wife's Cavalier and found that there was a slight catch in the alternator bearings and stiffness in the rotationthat was masked by the engine noise. It turned out to be one of the components of the major noise the engine made at 55 mph. I've also got to change the dynamic tensioner on her car as well, it's got a hitch in its get-a-long too.

 

Hey TJ,

I was looking for some answers to thesame noise coming from my serp. belt area.The P/S belt looks newalthough theserp. belt looks badly worn on the topside as if it has been dragging, and the bottom gatorback side looks new as well, anyway I was hoping to hear how you made out with the idler pulley replacement. If your noise had gone away or not.
Thanks.
Carl
96 Sebring 2.5L Conv. 75500mi

 

I have found "whirring" noise to be mostly related to alternators, and occasionally idlers, but idlers usually "scream" at me. My 97 Power Steering Pump makes some unusual sounds, but they tend to be more toward a "growl".

Hint: If you have to take the serpentine belt off and it is more than one year old, replace it. Especially if it has any markings or polished surfaces on either side. Both sides of the belt are required to be in decent condition in order to be effective. If the back (smooth) is badly scored or heavily polished, check out your water pump and idlers. If the inside (grooved) is cracked or polished it will make all different kinds of noises as it passes over the various peripherals.

Lastly, clean the surfaces of the different rollers that the belt comes into contact with. Oil, dirt, etc will wreck havoc with a new belt. Also be sure that your various body/water shields are in place and secure.