To the guy with the Volvo S70... (2/6/10 show)

The noise you’re hearing is the Emissions Air Pump. Same thing happened to me last year. You’ll figure it out when the noise goes away and you finally get the check engine light and the emissions code. On my car, the pump was under the battery. I figured it out because one of the hoses coming from around that area was vibrating heavily when the noise was going on. It’s a pricey part to replace. Good luck.

Ravioliworld is absolutely right…it’s the secondary air pump. I’m surprised Click & Clack missed this…'98 Volvos are NOTORIOUS for this failure, and it’s expensive to fix. I’ve got a '98 S70 GLT like the caller’s, and my second pump has failed (it’s a poor design that allows water to collect in the pump.) I’m just living with the check engine light for now.

I concur! When I heard the call and the fellas diagnosed a pulley/tension I was jumping up and down. Understanding the “better safe than sorry” motto I can see the logic behind the diagnosis. These pumps will make lots of noise, but are still functional. You CAN actually rebuild/repair the pump with a bit of time. Nearly EVERYTHING on these Volvos are repairable without actually replacing parts.

Fourth vote for the air pump.

Mine is pretty noisy – at 184,000 miles – too. The guts of the pump are replaceable with cheaper non-Volvo parts, I think. Try searching the various Volvo boards.