300e troubles
 

I just got a 124 300E 1990 model it has 100000kms. its a very nice car but there are a few issues with it.

1) The car vibrates a little bit on idle and I can smell a bit of fuel from the exhaust. but when driving its fine.

2) I changed the spark plugs but when i pulled the spark plugs out of the back 3 cylinders only they had a bit of oil on the thread but nothing on the tip the front 3 were fine (they were gapped at 0.8mm), also i noticed that the white bit under the sparky bit has spots of brown on it, any ideas??

3) Its drinking heaps of fuel.

4) The car has an 87C thermostat what should be the normal operating temperature??


Upon evaluating these issues I'm thinking the ignition timing is out, the fuel mixture needs to be adjusted through the top of the air cleaner housing (I'm not sure how to do this).


If anyone has any other ideas or suggestions please let me know.

What kind of spark plugs did you use?

87C is the correct thermostat.

Do a search you should find a lot of your questions have already been answered :)

Vibration at idle is a symptom of worn motor mounts...get them inspected.

300 troubles
 

The 103 engine has what MB techs call a twitch at idle. I don't know how the bad the viration is. I would take a look at the injectors. If they haven't been replaced, they should be. Also check the compression in all cylinders (should be approx. 95 psiG). You can get at the mixture adjustment by removing an aluminium plug in the top of the fuel distributor/flowmeter housing. I recall that you will need a 3 mm allen wrench (it's been awhile since I have done this). You should get between 20-25 mpg with this engine.

The plugs are Bocsh plugs