Hi. I have an old E190. Purple Blue. It is really cool. I got it cheap for 18 months ago. So far so good. But the switch that should turn on and off the ventilator for the engine broke, and I did not know about this before the engine got very overheated. Now the switch is fixed, but sometimes the oil pressure drops if I am in traffic jams. This is not a big problem, but there is a sound (a rattling sound) when I go over 20km/h in first gear and over 40 in 2nd gear and over 60 in 3rd gear. When the engine is hot it is almost imposible to drive without rattling sounds. What can it be. I had the oil changed and the mecanik said "that's nothing". But it anoys me a bit. Any easy fixes???

When the window is open(car standing still close to wall)it kind of sounds like the sound comes from behind the car, but I guess it must be the engine.

 

By the way the mechanic said that maybe it is the fuel pump. Anyone ever had a rattling sound, that was easy to fix?

 

Make sure I am understanding you correctly.
Your car overheated, now you have low oil pressure at idle and a rattle sound.

Now using low grade fuel when the car specifically requires high-octane fuel (as stated inside the fuel door) will cause the car to predetonate in the cylinders, which will make the car run hot and the valves rattle. Have you been cheating on the fuel?

The low oil pressure bothers me. If the oil light is coming on , you do not need to be driving the vehicle until it is repaired. If the vehicle has very high mileage, your mechanic might recommend using a slightly thicker straight weight oil to buy some time. There is a chance that the "oil pressure sender" is faulty, but you need to "know" what is wrong with your car. Oil pressure loss will ruin you engine.

The rattle "could" be your catalytic converter. "When it cools off", bang on it with your hand to see if it rattles.

Blue

 

Thank you. I will check the this, and have another mechanic check it as well. Recently I brought it to NCT (national car test) and they messure emissions, and it failed because of a crack in the exhaust. I got this welded. Then I passed the test, and the engineer said my engine was still good. Thanks for the input.