PeachParts Mercedes-Benz Forum - View Single Post

tinypanzer · #14 05-04-2009, 06:26 PM

Hey, great score. How many miles?

I think it quite odd that the engine was replaced. M103 motors are beefy little buggers and can take a lot of punishment. More likely is that the head was pulled to address a leaking head gasket. If so, then great because that's one PITA job you won't have to do.

As some have noted, that's a LOT of car to be pulled around by an engine that size. Unless it is running well, you will find it extremely sluggish. Running properly, it's no speed demon but you will find it to be plenty adequate, especially at highway speeds.

Here's a list of things I did to my 300SE all of which improved the performance of the motor:

1) Fuel pump and filter. If your pump has more than 100K miles on it, just replace it to be sure. These cars use mechanical injection and fuel pressure must be spot on for it to work correctly.

2) Distributor cap, rotor, wires and plugs are all a BIG deal on this car. Easy to replace, but need to be in good shape for the car to run well.

3) Temperature sensors. Very important for power and economy as well as ease of starting. Check the coolant and intake air temperature sensors and replace if out of spec.

4) Vacuum leaks. If you have a big vacuum leak the car will run like crap. There are several places to look on a 300SE. Check the air hose from the valve cover to the intake manifold. Also check the idle air hoses. Basically check every rubber hose under the hood and replace if suspect. One other spot is the rubber boot thingy that mates the air meter bowl to the intake manifold. I would expect that if your engine was truly replaced, those might not be issues unless the replacement was done a long time ago.

Take a deep breath and relax.... You've got a great car, and it seems like it was just allowed to deteriorate a bit. All of it should be readily fixable. You might spend some money doing it but, even if you spent $2K doing the suspension and motor mounts, the steering, ball joints, etc.... that's still less that what the car is worth and there's NO way to come close to that quality a vehicle in that price range. That car was $50K+ when new!

Stick around this forum. Things will crop up and the folks here are simply amazing in their level of knowledge. There are some real experts here and they have helped me solve all sorts of issues. These cars get a little finicky with age, but with perseverance and a little money you will be rewarded with a truly special car.

Check the A/C and climate control. If the A/C is out, that could be very expensive. Barring a shot motor or trans, that's about the most expensive single thing you're likely to run into on this car.