You really should try to vocalize the sound and attached it as an audio file to your message. It probably wouldn't help, but is usually quite entertaining ;-)

Joking aside, the real mechanics would be able to help more than me, but since they haven't yet....

First, from your post it could be one of many things, some not so harmful to the car and others quite harmful. Since you are already bringing it to a shop this afternoon, it sound like you're on top of it. If you don't trust the shop to which you are bring the car (and you don't have other options), tell them you want a record of all the codes the car's computer has stored.

If they don't have a Volvo Scanning Tool (VST) or satellite based diagnostic system (forgot the name???), you should be hesitant to bring it to them. If they don't have any OBDII scanning tool at all, or they don't plan on using one, you should bring it to another shop. Whatever scanning tool they use, have them write down the codes read from the OBDII connector and give tell them to you when they call you with an estimate. Then report back to this board with the codes before authorizing the repairs.

A note about OBDII scanning tools: I work on only my own car (1998 V70) and I only have a generic OBDII scanning tools. I don't have the Volvo Scanning Tools because it costs about $3500, but I don't charge other people to fix their cars either. In other words, by far the best diagnosis of you problem willl be done by a good mechanic who has a VST in hand. The second best job will be done by a good mechanic with a scanning tool which cannot read Volvo's proprietary codes generated by the cars computer. (Yes, it has gotten that high tech!) The difference in properly diagnosing your problem can be a $1000.









When was the timing belt last replaced and how many miles are on the car?