The compressor on my '91 240 with 175k miles, auto tranny, is short-cycling, about 3-4 seconds on, 3-4 off. It does this only at speed and usually under a load, typically while going through third gear before shifting into overdrive, not when idling. It's cooling well, but the forum says this is a sign of low R12. I can't find anybody willing to recharge it for me, so I'm thinking of doing the R134 conversion.

An independent shop that I trust estimates $250. The dealer is quoting $1200, including the evaporator, hoses, and I don't know what else. So:

1) Since it's cooling well, is the constant short-cycling even an issue, besides annoying me because it drags on the engine?

2) Is $1200 a ripoff? Is $250 too low?

3) Anybody know a shop in the DC area that would be willing to give me a shot of R12?

Keep in mind that I'm not mechanical and I have no workspace, so doing anything myself is not an option.

Thanks!