your supercharger will be constantly "pumping", meaning trying to compress air, being spun by the belt on the front of the motor. On the top front of the SC assembly, beneath the black "box" resonator, is the bypass valve, which functions much the same way as a blow off valve on a turbo setup. It's job is to release the air pressure between the supercharger and engine. This is the only thing that can cause your supercharger to not build boost/pressure aside from a leak in your intake/inter-cooler piping. If you look at the pulley on the front of the supercharger and it is spinning while the car is running, it should be fine. If you are not getting boost, your bypass valve could be stuck open, or there could be some of the intake piping loose...or the car could be keeping that valve open for some reason, but those are the things that would prevent it from building boost.
Sorry, i just realized you have a 200. I am not sure what exactly the differences are between that and the 230, but from what i can tell, they are very similar, but with less engine displacement, so what I mentioned should still apply. Are you having trouble with your car? If you are, give us some more details of the symptoms and we can better point you in the right direction.
Thanks for the advice appreciate it , and yes i believe that there is something not right with the S/C because sometimes the car goes like a rocket and then some days it is just a normal 2L with no oomph
I would suggest at least taking a look at that bypass valve to see if it needs to be cleaned out. Sometimes they can stick (from oil buildup from the air/oil separator and dust). Personally, I would just take it off and clean it with carb cleaner and a soft brush. It is possible that the bypass valve itself is failing and needs to be replaced. I have no clue how likely that is, just worth mentioning. Aside from that being the issue, it may be the ecu keeping it open for some reason. If cleaning it out doesn't help, I would get it scanned with a mercedes specific scanner tool to see if there is a trouble code that would indicate a problem. The supercharger itself is most likely fine since it is intermittent. I finally found a picture of the 200 engine bay, and it looks nearly identical, so this should all apply to your car. The bypass valve is the silver part at the bottom of this photo.
Thnx again for all the support and advice , the bypass valve was not sticky at all what i did do is opening that bypass valve and i found that all the gears and mechanics inside is badly worn with excessive play on the elect motor shaft and intermediate gear ,i just dont know where i am going to find such a valve here in SA or do you think it is possible to import it from you guys