Hello Allan,

The change was done on my 78 300d. The compressor was bad so I had to replace it with a new one along with a new rec./dryer and expansion valve which is located behind the glove box. All was simple except for the removal of the York compresson which on this year is located on the top left side of the engine. You have to take off a lot of things inorder to get it off. The new York came with the different oil for the R134. No hoses were changed and it works great. If your compressor is O.K. all you have to do is change the oil to work with the R134. I did a lot of research and got a lot of different info from almost everyone. Some say the pressure is higher on the R134. I found this not to be true for at least on my car. The fitting that allows the gas to enter the system had to be change... I believe so... It cools down just fine now. Thanks Gregg