The oil I have to choose is for my parents car, a '98 Ford Galaxy van with 117.000 km on the clock. Ford wants a 5w-30 meeting WSS-M2C 912a. Because of all their short trips and "cold engine high speed driving", I got their shop to fill it with Mobil 1 0w-30 for the last three oil changes. From now on, we will be changing the oil ourselves, wondering what's the best oil for this application. Is there anything special inside the 2.3 DOHC that does not allow us to use any 0w-30 ACEA A1 or A5 lubricant? AFAIK, Ford was among the first to specify engine oil with an HTHS viscosity below 3.5 in Europe. Fuel economy is likely to be the main issue with the WSS-M2C 912a specification. WSS-M2C 912a has long been replaced by WSS-M2c 913a and in my opinion many oil formulas will exceed the old standard. Fully synthetic 0w-30 HTHS >2.9 lubricants are getting rare, while Mobil 1 0w-30 is the only one meeting a current Ford specification. The M1 0w-30 sold in Europe is actually different from the one in the U.S. M1 0w-30 API SL Another easily accessible type of products is VW approved long life pumpe düse stuff. One could expect better AW properties with VW 503.00/506.00/506.01 lubricants vs. Ford spec. oil, but do these properties help in a Ford engine? Also, there are plenty of ACEA A3 0w-30 lubricants available, such as Castrol SLX longtec. These oils are more viscous over the entire temperature range and I do think we need an HTHS >3.5. What would you guys advice us to do?