I'm going to buy an old benz. The choice is a W123 300D (or 300TD) or W126 300SD. There's a local 1979 300TD but its not a turbo, and there's a fairly good 1984 300SD three hours away.

We put 50,000 Km (on average) per year on a car, mostly on 2-lane 80Km/hr highways, although if we want to drive to Toronto, we have to get on #11, then #400, then #401 (100+ Km/hr expressways).

Other than aesthetics, looks, whatever, is there any difference in the longevity or ongoing maintenance costs between the W123 and the W126?

What does having a turbo do to longevity or maintenance or repair costs compared to no turbo?

The 300SD is longer but not a wagon. When travelling in our current Pontiac wagon, I don't like things higher than the windows. Which would have more room for stuff (two people and a dog): A 300TD with stuff to the bottom of the windows, or a 300SD with stuff in the trunk?

Thanks,

Doug.

 

I've had two local mechanics say that the non-turbo will have lower repair costs over time. One also said that the number-one killer of the turbo is that people go to a lube shop to get the oil changed and they don't prime the turbo before they have you start the car.

I've checked the Chiltons from the library (and a W123 Haines) and neither says anything about priming the turbo when changing the oil. How do you prime the turbo?

I've also heard that after even a short drive you need to let the car idle to cool the turbo before shutting it down (e.g. when going to buy groceries). Is this true? Is there another option (e.g. a post-shutdown electric oil pump)?

I'm sure some of this is in the owner's manual but I don't have one.