with the w124, assuming you have a car that you or the prior owner had completed the wiring harness and head gasket replacement for the DOHC cars (I assume- correct me if I'm wrong, but I assume once these 2 items are fixed, they are more or less upgraded and fixed for good), would it be an above average reliable car (factoring in age and mileage)?

If so, it seems to me being someone interested in a used w124, that if I found a car that had these 2 items fixed, it should be a solidly built overall relable car, barring any "normal" things for a car so old (things like HVAC control, power antenna, radio included as potential issues down the road). I may be off base as I'm new to the w124 wrold, but this is my observation from here and in reading the mercedes buyers guide (forget the authors name right now, but it seems to be a popular book)...

w124 is nothing but problems once it's past the 150K mile mark. what's worse is that normal shops who are used to working on domestic or japanese cars don't want to deal with the mercedes even for simple issues like a/c etc. the cost becomes quite an issue after a while. I suggest stick to the newer models, buy the most expensive car that fits your budget with the lowest mileage.
good luck.

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