Pristine Auto Detail
1323 Rollins Rd
Burlingame, CA 94010
(650) 342-1660‎
I had them do a steam cleaning of my near 40 year old Porsche engine and they did a nice job at a reasonable price. They do detailing as well but can't vouch for that as at the time my paint was in pretty bad disrepair.
If you want to get your engine steam cleaned I don't think there is anyone in the city that can do it if I remember right.