Does your diesel have a louder idle at higher elevations?

[DieselAddict]

Of my 3 cars my 87 300D is the only that I've taken down to the lower elevation of central California and the Bay Area and I immediately noticed how much quieter the car idled over there compared to over here at 5000 ft where it has pretty loud diesel clatter. I've done just about everything on this car: inspected timing chain (2 degress stretched), injection timing, injectors, replaced delivery valves, air filter, fuel filters, ran Diesel Purge and using Mobil 1 synthetic. I'm starting to think that I have low compression, but maybe this behavior is normal as the thinner air at higher elevations effectively reduces compression. I'd like to hear from others who have taken their diesels to the moutains and back and listened to the idle.