What are the most common problems with a Mercedes-Benz 300?

At MOT, coil springs and corroded fuel pipes are flagged more often than on other cars the same age.

What should I ask the seller before buying a used Mercedes-Benz 300?

Any recent work on the coil springs? (Flagged at MOT 2.1× as often on the Mercedes-Benz 300 as on other cars the same age.) Any recent work on the corroded fuel pipes? (Flagged at MOT 2.6× as often on the Mercedes-Benz 300 as on other cars the same age.) Can I see the service history and receipts for any big jobs?

Used car guide · 1955–2005

Mercedes-Benz 300 common problems and MOT failures

What goes wrong on a used Mercedes-Benz 300, year by year: known faults from UK buying guides, the parts flagged at MOT more than on other cars (from 3,752 MOTs done during 2023–2025), and what to check before you buy one.

3,752MOTs done in 2023–2025, all years of this model

9,962on the UK register

Pick the year

Most years have their own guide. The year is when the car was first registered (it’s on the logbook, or check the reg below).

2005 2004 2003 2002 2001 2000 1999 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985 1984 1983 1982 1981 1980 1979 1978 1977 1976 1975 1974 1973 1972 1971 1965 1955

What usually goes wrong with a Mercedes-Benz 300?

We haven’t found widely reported faults for the Mercedes-Benz 300 in the UK buying guides we use yet. That doesn’t mean it has none, so check the car carefully and look at the MOT weak spots below.

Common Mercedes-Benz 300 MOT failures to check

Parts flagged at MOT well above the usual rate for cars the same age, for each fuel on its own. From the DVSA’s results for every MOT done in Great Britain during 2023–2025.

Petrol

Ball joint dust cover
up to 2.3× usual

Stands out on cars registered in 1990, 1991 and 1992.

Rough price £60–£150 (one joint) ClickMechanic

At the viewing: Listen for knocking over bumps and check the rubber boots behind the wheels aren't split.
Coil springs
up to 2.1× usual

Stands out on cars registered in 1990, 1991 and 1992.

Rough price £175–£400 (pair, one axle) ClickMechanic

At the viewing: Look behind each wheel for a snapped spring coil, and listen for a clunk or twang when turning the wheel lock to lock with the car stopped.

Mercedes-Benz 300 MOT pass rate by year

Older cars fail more, so compare each year with all cars registered the same year.

Year	Pass first time	All cars that year	MOT tests
1993	73%	68% +5	609
1992	76%	69% +7	1,161
1991	73%	71% +2	1,101
1990	75%	72% +3	881

Questions to ask the seller before buying a Mercedes-Benz 300

Ask before you travel to see it. A seller who knows the car will have answers, and receipts.

Any recent work on the coil springs? (Flagged at MOT 2.1× as often on the Mercedes-Benz 300 as on other cars the same age.)
Any recent work on the corroded fuel pipes? (Flagged at MOT 2.6× as often on the Mercedes-Benz 300 as on other cars the same age.)
Can I see the service history and receipts for any big jobs?

Looking at a Mercedes-Benz 300?

Check the actual car: its own MOT history, whether it already shows these weak spots and what to ask the seller. Free, no sign-up.

Where this comes from: MOT figures are the DVSA’s anonymised results for every MOT test done in Great Britain during 2023–2025, grouped by the year each car was first registered. How many are on the road is from the Department for Transport’s vehicle licensing statistics. Known faults are from UK buying guides, in our own words, with links. How we score