I am considering buying a 93 940. I have yet to drive the car but the price seems good and a Carfax search only revealed what I was already told (see item 1 below). Questions:

1. Carfax indicates that it is a 2.3L L4 FI SOHC. There is a nameplate on the back indicating that it is a GL but I know that the auto was in a rear collision some years ago and wondered if the "L4" designation indeed means that it is a turbo. It does have the spoiler and leather seats which may further identify it as GL.

2. The owner says that it is an R-14 refrigerant system. I currently own a 1994 940 which is R-134. Can someone confirm that Volvo made the R-14 to R-134 transition in 1994? If so, what is the complexity in converting a Volvo R-14 system to R-134 on a Volvo? I'm pretty good at AC work but don't relish the idea or replacing major components like the compressor or expansion valve or all the seals due to an oil/refrigerant compatibility problem.

3. The owner says the check engine light is on and that he was told that it was a knock sensor problem. Is this is indeed the case, is this a difficult and/or expensive proposition to change it?

Thanks in advance to the kind Brickboard team who have saved me much time and money in the past with their considerable knowledge.

Best regards,
Ron