Etiquette and protocol question on compression testing a vehicle.....
 

If one were interested in purchasing a 25 plus year old diesel Benz (say 300SD, 300D, 240D) is it being too forward and cheeky to ask to do a compression check and to make the offer contingent on the results.

Does anyone out there see such a request as reasonable?? I feel it might be "pushing the limits" of reasonable behavior.

Were I the seller I would want some contingencies before I would allow anybody to invade my precious (to me anyway!!) engine.

I don't think it's out of line. I'd offer to go 50/50 with the owner to have a mechanic of his choice to the work. Reason being that even if you don't end up buying the car, the owner will have the compression information at hand for anyone else who asks.

Its called a pre-purchase inspection (PPI). I wouldn't buy a used car without doing one.

I would not hesitate to ask. You are about to plunk down a good sum of cash. If the owner is concerned about cross threading or some other damage, I agree that you can offer to have a professional mechanic do it.

It may not be the norm, but for any car that I have sold, I have been very forthright about any problems with the car, and have priced it accordingly. I expect the same from others and if they are embarrassed about something I have found that they knew about and were not telling, shame on them. My approach is to establish what the seller wants, and ask if there are any problems that I should know about. Then if I find problems during my inspection, my offer goes down accordingly.