As these cars aged real efforts to maintain them declined. In all too many cases they were just treated as old cars. There is no dispute about this really as that is understandable. For possibly the majority of them.

In my opinion just do a total maintenance run on any example you are not sure of. As a general rule you should not believe the indicated odometer readings either. If you are very lucky perhaps some owner not long before you acquired it did this. Or there are records you possess that came with the vehicle.

If there are physical indications the accumulated milage is not too great. I think they can be a very reliable car after a real check up. Fortunately it involves more time than money. Remember it is 40 years old. So there is a lot to check.

I have a really soft spot for these cars. Also believing nothing like them will ever be manufactured again. Rust and extremely high accumulated milage are their downfall. At least for practicality. Our kids years ago would tell the wife dad is coming home in the tractor. Like the dogs they heard them before they came into sight as our house is built on the leeward side of a hill.

The car you acquired was a very high quality car when it was new. This makes a major difference now. Also welcome to the site. This site makes a real difference to owners of these cars. As mentioned checking the valves and at the same time checking for too much wear in the timing chain. The valves required checking every fifteen thousand miles. If for example this has been ignored you may have to adjust them. Drive the car for a few hundred miles and check them again. Carbon can build up on the seats that will get pounded off closing the valve clearances up again. If they have not been adjusted for decades.

Since you are going at the brakes. If the brake fluid is anything but pretty clear. Change it. If the car is drivable take it for a short drive and coast to a stop before starting the brakes. Check each wheel for temperature. You have eight caliper pistons and now is the time to check them initially for dragging. If not hit the brake pedal and check that the wheel has released. Then repeat this for each wheel. The rubber brake hoses should also be changed out if they are old. I am not for pumping an old master cylinder to bleed the brakes. There are other methods if you have to. In other words tackle the brakes in a restoration approach. Check everything carefully.

Fortunatly any parts if needed are reasonable in price still and available for this brake system. They had a really good brake system when new and it really is not that hard to get it back. Perhaps this is also a good time to clean and check and repack the front wheel bearings as well. They are pretty long lasting on these cars if not totally neglected. Even neglected they have done well in general.

I attribute this to quality. In setting them back up a dial gauge should be employed. Almost everything and the best way to tackle it is somewhere on this site.

I believe you have the non turbo engine the same as in my 1977 300d for all practical purposes. Checked over and in decent condition mine seems okay on power. To me there are three indicators of initial engine condition before any work on them.

Where is the oil pressure gauge after the engine is at operating temperature at hot idle? What does the oil cap do if loose? A little dancing is fine but it should not be blowing off. Plus how many miles per quart of base oil consumption is occurring.. Making sure there is no signifigant engine leakages present.

Piston speed on the highway is somewhat higher than the turbo engines as your car has a higher ratio rear end. The piston rings are possibly less efficient at dealing with the oil I personally believe. Especially in the four cylinder 616 engines. Where the rear end ratio is even worse. So some base oil usage is not as signifigant in comparison to the turbo engine versions. Again these are just my opinions.

I know I can do a massive amount of checking and mechanical refurbishing if needed for less cost. That being far from home with a roadside breakdown today because I did not. Where you are generally at the mercy of those that get you going again. If you can even find anyone there to work on it.

Suprising enough the majority of these engines still do pretty good in these simple tests.