Thanks for the clarification on the non-klima equipped 300d; now I can stop looking for it. Re: other suggestions, I tried uplugging the aux water pump and had installed a new dash temp sensor and put the aspirator tube back the way its supposed to be. But I like the sound of that over temp cutoff sensor idea and will spend some time looking for it now. Problem does indeed seem to manifest itself after the engine temp tops out on the gauge and is worst on the highway when the temp is a bit higher than around town (also might explain why the problem is worse in really hot weather when the AC is really necessary ). Can someone confirm whether an 82 300d has one of those and perhaps how it can be tested before replacing it? Will unplugging it allow the AC to continue running if its at fault, or simply shut down the system? Or I'll do that test if I can find the sensor and let you know what happens.