sorry silly question but I had to replace my m113 intake manifold to fix a big air leak (manifold itself had deteriorated and would suck air in through the housing itself) and did not pay much attention when taking things apart and now I can't figure out what covers this hole in the driver side front cylinder head - see pics.
It looks like it goes down to the crankcase but I am puzzled what part goes on top? Right in front of the right secondary air injection valve.

Thanks for any quick help - trying to get this car back on the road.
2001 CLK 55

This hole is empty, not sure if it for vent or something, just leave it, don't worry about it..

-;-ZAYED-;-

thank you much Zayed - almost figured it must remain uncovered since I didn't have anything lying around that would go back there

one follow up question - I broke off the round metal sleeve of one of the secondary air injection valves when trying to remove it -is it ok to just put sealant on when putting it back or do people replace the whole valve when that happens ?

Do you have a secondary air pump, or your CLK55 doesn't come with it..??

-;-ZAYED-;-

yes, has secondary air pump - it's a California spec car

While you have secondary air pump, it's so important to get this shutoff valve, cause it's opened & closed via air pump switchover valve,,

L&R shutoff valves are the main parts of accurate air injection system..

-;-ZAYED-;-

got it - i may just replace it then - the valve itself is still in good shape but the metal sleeve on its base that inserts into the cylinder head broke off when I removed it - so now it's only held by the bolt that secures it and the manifold.

I might try to seal it with sealant and if that doesn't work replace it

thanks much Zayed !