Make sure it isn't a rusty example, these W116 bodied cars did tend to rust out. Look under the carpets, trunk mat, the lower body, the jack points. Might even want to run it through an auto car wash to see if there are leaks in it

'75 was the first year for the catalytic converter, and they were mounted under the hood, so there could be a problem with overheating the engine wiring, underhood fires and such. In 1977 the catalytic converter was moved downstream, and the problem was solved.

If I owned one of these, and my state didn't have emissions inspections and I was never going to sell the car, I'd consider removing the catalyst or gutting it

These cars were big, heavy, thirsty, safe highway haulers that still look imposing today. Very durable and reliable. These cars very exspensive when new, were built to the highest old world Mercedes quality, and with cost no object, engineering standards at their highest, and this model was built utilizing every possible innovation from the ESV (experimental safety vehicle) so for its time, it was about the safest car on the road.

Spares are still available in junkyards but no longer abound.

One neat plus is the car comes to you with free Mercedes Roadside assistance, 1-800-formercedes gets a free battery jump, delivery of 2-3 gallons of gas, and flat tire changing. It devolves to any owner of any Mercedes Benz. Great service, just used it this year.

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1991 560 SEC AMG, 199k <---- 300 hp 10:1 ECE euro HV ...

1995 E 420, 170k "The Red Plum" (sold)

2015 BMW 535i xdrive awd Stage 1 DINAN, 6k, <----364 hp

1967 Mercury Cougar, 49k

2013 Jaguar XF, 20k <----340 hp Supercharged, All Wheel Drive (sold)