I have no experience with a "prefessional" engine cleaning, but Pep Boys et al sell "Engine Flush" or something for much less than $200, but I've never used that, either. I think it's just a solvent intended to thin the goop and lift some deposits before you drain the oil. Synthetic oil has many benefits, but there's nothing magic about it. It is not designed to clean the engine, but because of it's purity it tends to have a cleaning effect. What kind of "goop" did you find in your oil pan? How often to you change the oil? Gus Schlachter Austin, TX VIN# 4695 > -----Original Message----- > From: doctor who [mailto:ohwrd@xxxx] > Sent: Friday, July 14, 2000 2:56 AM > Subject: [DML] internal engine cleaning > > I have a high mileage engine and based on the goop i have seen on > the bottom of the oil filler cap have been considering having this > internal engine cleaning done to my vehicle. > > I was also considering switching over to sythetic type oil > and i had heard a rumour that it is recommended that you have > your engined > flushed first before switching...