I've been gearing up to replace the seized compressor in my 93 240. I thought it was going to be a simple R&R, but the more I get into the job, the more questions pop up. So:

After some research, I've decided to exchange the NLA Seiko-Seiki SS-121DS5 for a more available (and hopefully more robust) Sanden SD7H15.

1/ From web searching, it appears that my original SS-121DS5 has a thermal cut-out and a High Pressure Relief Valve (HPRV). I cannot find a Sanden with a thermal cutout, but I think can get one with or without a HPRV. Should I get one with he HPRV head or not? Also, should I find a way to install a thermal cutout?

2/ The original SS-121DS5 has a 122mm clutch. Since I cannot find the displacement/rev for this compressor I am not certain whether to get the Sanden with a 125mm or 132mm clutch. I have a feeling that the Seiko might have less displacement than the Sanden and needs to be overdriven to make up for it, hence the smaller diameter clutch. Can anyone recommend which clutch to go with?

My 93 cooled well enough, but just well enough; I do not want to do anything bone-headed that changes that.

Also, if anyone has done this swap, I would love to hear about it.

Thanks, one and all,
Rich (near Pittsburgh)