I bought a 2006 xc70 about a month ago so that I could give the 940 a break from winter duties and because it only cost me a thousand dollars--Canadian! About three hundred U.S. I understand.

Regardless, it has an 'error message' screen that sometimes yells at me that the oil pressure is low and that I should stop the engine. This only happens when stopped at an intersection and the revs intermittently drop below a thousand rpm. I get rid of the message by slightly raising the rpm.

I have been researching the issue on the xc70 site and oil sludge has emerged as a possible culprit and that moving from regular oil to synthetic will gradually remove the sludge and perhaps get rid of the error message.

What are your thoughts on using synthetic oil? And if it is a good idea, what would be a good replacement oil for an xc70---or a 940 for that matter?

p.s. 940 is running well. I hope to be back in her in the spring.