Diesel engines increasingly turn into causes for divorce in the promiscuous automotive business. PSA Peugeot Citroen and Ford are calling off some of their diesel dalliances.

While heaping praise on a 12 year cohabitation that produced “more than 20 million engines in two displacement families (1.4-litre to 1.6-litre and 2.0-litre and above),” a joint statement by PSA and Ford says that they will no longer cooperate making bigger bore diesels. Or, as the statement says in an emotionally responsible manner:

“The two companies have decided to independently develop and manufacture their larger diesel engines (2.0-litre and above) to meet their future needs as well as new regulations. This decision has no impact on the current production of the existing jointly-developed diesel engines.”

When GM and Peugeot decided to shack up together in a broad based alliance, “Peugeot had said the tie-up would not affect existing partnerships including joint diesel-engine production with Ford,” Reuters can’t help remarking

Peugeot and Ford will continue to cooperate on smaller diesels and a new generation of engines developed to meet new European emissions rules entering into force in 2014, the companies said.

We all know what happened to Suzuki and Volkswagen after Fiat sold diesel engines to Japan.