Interesting Ed, I have passed this on to Dan Goy who runs Baja Amigos caravans who has maintained diesel in S Baja is ULSD. it would be interesting to take a sample in Cabo. On the caravans I led this year about 1/3 had late model diesels and none had any issues with Mexican diesel, at least not as far as I know. I would estimate most went through about 10 tanks. I have also been in touch with Pierre Blais who runs Amigos Rodantes out of Quebec His caravans consist of a lot of late model diesels including his own which is a Mercedes. Since he takes trips all the way to the Yucatan his customers are going through about 15 tankfuls. Once again he claims no one has had issues. I also spoke to Serge Loriaux who owns Caravanes Soliel. He took 150 rigs down this year about 50% of which were late model Diesel Class A's. Also no issues. I think it is likely anyone taking late model diesels down there will have particle filter life reduced. As to other issues, its debatable. I just sold my truck, but since i take 2 return trips a year I have bought an early 2007 Dodge Ram. I did this because its hard to get a Duramax worked on down there.
I suspect with the drop in fuel prices, the conversion to ULSD will once again be delayed.
It would be interesting to test samples from Mexico City or guadalajara that do supposedly have ULSD. I did see one station 2 years ago near mexico City that had it on their sign.
