Thank you, Klaus.
You are vey kind to respond so quickly. Your message is really confirming my suspicion that the dealer is giving me the run around and charging me for unnecessary repairs.
Another mechanic I had before using the dealer was not very reliable, either... he kept missing things and was not available when needed.
Getting anything for Volvos out here is not easy, the best thing would be to do it one's self. Unfortunately I don't have the experience or the time for it.
I want to know what is going on and am learning about it, so I can at least tell them what I want to have done.
For example this guy telling me about the 'core temperature sensor'. We had a long conversation on the phone about it while I asked him what its function was. He could not really come up with an answer, kept repeating himself. But since I had not enough information, I did not insist. I searched all over for such a description... couldn't find one, and then your message confirmed that there is no such thing.

Just a couple of months ago, I had two sensors replaced: the EGR (my bill states that the o2 sensors and MAF mass air flow sensor contacts and airbox were cleaned.)
The EGR temp sensor was replaced and the
O2 sensor, as well. For the parts he charged me 250.36 and 282.48, not including labor....
A few months ago, (End of July 06) I had the
EGR controller and the
suppressor relay repaired, including the
EGR vacuum connection.
(The part of EGR vacuum con was 236.03, the relay 63.22, again of course not including labor.

Any idea how all these parts are related? The EGR vacuum connection, the EGR controller, the EGR Temp sensor, the O2 sensor.?

Thanks for your input.
If you get a chance.. let me know what you think.
I am calling the dealer, (i.e., the service technician) early in the morning to question the work he wants to perform.
I have no trouble paying for good service and don't question anyone as a rule, but lately I have become suspicous, because I have spent a fortune on my car and keep getting the answer: well, your car is old. It is very well kept, and has about 160.00 miles on it. I don't consider that old. Especially since so many parts have been replaced. I think that a good car like a Volvo can last much longer when kept up.

Regards.
Ilse