It would be a good idea to use a good engine flush (such as made by AMSOIL or BG). If you don't, or won't, flush, then go ahead and change the oil. If you see any indication of sudden increase in oil consumption after a couple of thousand miles, change the filter and top off. You may want to drop the first batch after 3-4,000 miles.

1. Use a new aluminum crush washer on the drain plug (17mm socket)
2. Do not overtighten the drain plug (26 ft/lbs)
3. Use a factory Volvo or Mann oil filter. Accept no substitutes (here come the flames!) eEuroParts.com sells factory Volvo filters for $4.95 alloemvolvoparts.com sells Mann W917's for $4.37
4. I use a good quality "dino" oil and change it every 3000. Many use synthetics. I ran only Mobil 1 10-30 in my last car, a '93 850GLT. I also had the rear main seal go. Are they related? I don't know for sure. I've chosen to run the dino oil because it is cheaper (Kendall 15-40 in a '96 855T) The choice is yours!
5. Consider replacing the oil cap gasket if it leaks or is old.
6. I always serviced the flame trap at each oil change in my N/A 850. I would clean it out, and blow compressed air through the hose (BEFORE draining the oil, and make sure the oil filler cap is removed!)
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RussB in Ct. - '96 855T- '91 940T - '93 850GLT (R.I.P. 6-16-02)