Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Brakes? Wheel bearing?

Ok, here’s my issue. My car (a 2004 V70 wagon that looks like a hearse) has recently begun making a cross between a hum and a moo when taking off from a stop. It doesn’t happen every time, it doesn’t matter if the car is warm or cold. It seems to only happen when I’m accelerating slowly to moderately and once I get to 10 mph, it goes away. I did rotors and pads all the way around about 10000 miles ago. The pads look good - as far as I can tell. The car has 78000 miles on it. I usually don’t hang onto cars this long, but I really like this thing. Thanks for your help!

Brakes and wheel bearings don’t hum or moo. It’s something else.

My guess would be a loose heat shield somewhere in the exhaust system. Simple to fix, usually, if you can figure out where it’s coming from.

Please note the word, “guess.” I can’t see the car and I can’t hear the noise.

I have some experience with mooing caused by heat shields (Taurus wagon, F250) and I don’t think that’s it. The sound is kind of like when a garbage truck or bus stop and they make that heavier high-pitched squeak/moan/moo sound.

I will try and throw it up on the hoist at work this week and look for anything heat shield or guard related.

This sounds like a loose or broken baffel in the muffler to me. It does not sound like a wheel bearing or rotor problem.