I started hearing a noise at the front of the engine yesterday that increases as rpms do and decreases as well. How can I tell if it is the waterpump, alternator, or ??? No water leaks or cooling issues. Alternator is charging. Suggestions? Thanks.

Get a long screw driver, 24 inch, put it on the alt and press your ear to it, it will amplify the sound coming from the alternator. If thats not it, probe around the motor to narrow it down. Also, check out the fan clutch.

A good piece of 3/4" hose works very well too. Or just steal your wifes work Stethoscope...

haha

Hmmmmmm.... Yes, good advice, but I don't know whether it's safe. Personally, I wouldn't put one end of a long screwdriver against a running alternator and the other end to my ear. Being a neuroscientist, I have visions of another Phineas Gage incident happening. Personally, I'd just stop the motor, loosen the belt, and wiggle around the various bearings by hand. You should feel roughness and play in the one that's complaining.

Yes, I'm with Fastwoman on the idea of safety first.

I had a similar situation where one of my idler pulleys for my A/C was making noises like yours. Once the bearings were removed and I had them in my hand, there was absolutely no way of telling they were the trouble makers.....only at operating speed, they were noisy!

Well that helps a lot doesn't it!

Despite the danger (real or apparent) the use of a long screwdriver as a stethoscope is common in my experience. A safer tool to use is a stethoscope designed for automotive diagnostic use.

Here is an example:

http://www.autozone.com/autozone/accessories/OEM-Mechanic-s-stethoscope/_/N-26gd;jsessionid=667EE9C7C8E07AAF4A9687F8649B8E81.diyprod3-b2c13?counter=0&itemIdentifier=70131_0_0_

can you describe the noise, and detail when it occurs?

Several years ago I drove from NC to Florida, and a squeal that had been intermittent became a full time ear splitting scream about 100 miles into the trip...

After making to my destination, I found a Nissan dealership. Luckily there was a Z guy there, and he (using the aforementioned screwdriver technique) found my issue to be the bearings in an Idler Pulley about to give up the ghost...

By the way Sarah, you put the handel to your ear, and the point on the part you want to diagnose, it's safer that way.

Well, true, but there's still no way I'd do it! I've really seen too many brain injury cases -- not specifically from that, of course. I don't think I'd use a screwdriver to listen to anything forward of the #2 cylinder. That's the bound of my comfort zone.

Thanks for your suggestions. I will get sometime to look at it this weekend.

Got the car out today and believe it is the idler pulley. I sprayed a little oil on it and it stopped making any noise. We will see how long that lasts.

Another clue would be to remove the water pump/alt belt next time it's making noise, then start the engine and listen. You'll just run off battery power and the engine won't overheat in the time it takes to see if the noise is still there or not.