I want to share the comments my mechanic made the other day. I went for a routine check-up + slight endine noise/vibration. (1990 300 E 70k)
1. Remove Bosch Platinum4 plugs as 103 engine allows oil to seep into the chamber and this reacts with platinum. I did and the spark plug heads were dirty - black (after 10k).
2. Out of the 6 injectors 3 are old style - black and the rest are new - gold (color). Some of the vibration could be attributed to misfiring/faulty injectors.
3. Engine mounts were old. Suggested replacement.
4. freon low - add/convert.
I bought the mounts (US$ 180 pair) and intend to replace them myself - any ideas, smth I should know about?
The plan is to put a jack under the oil pan (with a board), loosen the bottom and top nuts (botton hexadecimal one 1st), lift the engine and swap the mounts. The pass side mount is easily accessible, but the driver's side looks like a pain.
Would you recommend changing the injectors? Myself?
Any thoughts from you guys - moderators and the rest - are appreciated as you seem to know so much about this stuff...