1974 Mercedes-Benz W107 450 SLC 4.5 petrol

Summary:

A lovely car once they are all in order!

Faults:

The motor on this car had not been looked after that well by the previous owner. A costly repair was necessary.

The timing chain needed replacing as well as the timing chain guides and tensioner.

The front crankshaft seal also needed replacing.

Camshaft feeder pipes were replaced.

Adjusted tappets to spec. These had never been adjusted and adjuster threads were seized.

Replaced vacuum advance.

Replaced water pump assembly.

Air pressure sensor replaced.

I'm currently replacing door and window rubbers as these have perished with age.

I also replaced the carpet with factory original material and had the front seats re-cushioned.

General Comments:

Once it was fixed it ran like a dream. These are lovely cars made for cruising, preferably at high speed!

It still has a few niggles which are expected from a 30 year old car.

Would you buy another car from this manufacturer? Yes

Review Date: 30th September, 2003

25th Nov 2006, 22:24

I recently bought a 450SLC with 103,000 miles and am enjoying it immensely. Here are the issues I've confronted:

-- Loud muffler: $7 in muffler bandage and muffler cement solved it!

-- Dashboard lights wouldn't come on: fixed by cleaning a fuse (fuses are notorious with the 107's, due to incompatible metals used in fuse system.

--High idle (about 1500 rpm) : Fixed by chasing down loose or corroded vacuum hoses (another MAJOR source of trouble with the D-Jetronic engines, which rely on manifold pressure to determine fuel requirements). Adjusted idle screw a few turns until 800 rpm reached. Total cost $3 for a bad hose going to manifold pressure sensor.

--Engines runs a bit rough or misses, especially when cold: Replacing ignition points and condenser helped tremendously; adding a bottle of Chevron techron additive to tank seems to have cured problem!

Have gone 1,400 miles and no measurable oil usage. A good sign!

8th Sep 2007, 08:13

Has anyone heard that replacing and upgrading the electronic fuel system is a must? I am told the 73 SLC had a complicated fuel system that should be upgraded to the 80"s version. Does anyone have any input or experience with this?

4th Mar 2010, 01:33

Update on my Nov. 2006 comment:

Happy to report that a remaining intermittent stumble has been cured. After eliminating many possible causes (accelerator switch hanging up, etc.), I finally figured it out: A sticking mechanical advance in the distributor. After dripping plenty of oil down the top of the rotor shaft, the problem has been resolved. I'll probably have to rebuild the distributor at some point, but until then it's doing fine. The problem would usually occur right after coming down to idle after a high speed run.

One other point: after adjusting the ignition points VERY carefully, the car no longer ha a "vacuum leak-type lag right off of idle. Completely gone!

So, a word to the wise. Although these cars do have complicated electronic fuel ignition, with $1,000 manifold pressure sensors and the like, drivability problems seem to almost always arise from the basics. They always say to check the ignition before messing with the fuel injection, and boy is that true with these cars.