I have a 90 420sel. There is a hose that goes in the top of the valve cover over to the idle control valve. The hose is in an approx. 90 degree angle when it leaves the valve cover and is about 3/4 or 1 inch in diameter at the valve cover and runs down to about 1/2 inch. Can anyone tell me what this would be called if I had to ask for one? Mine has a crack in it and needs to be replaced. Thanks for any help.

Good description. I don't know what it is really called either, something to do with idle air or crankcase ventilation.

Call Phil @ Fastlane, I am sure he will know

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Chas

Had a 380SL, 450SL, 380SEL, 420SEL, 500SEL

Got a Euro 500SEC right now.

That may be the PCV (positive crankcase ventilation) hose, you should also be aware that at the bottom of the port is an orifice that needs to be cleared occasionally. The valve cover side is somewhat of an open connection, this allows crankcase vapors to be drawn into the intake system. The hose that connects underneath the air cleaner is the fresh air intake part of the PCV, the positive ventilation portion.

If you need part numbers let us know.

Thanks all for your help. This hose is just in front (grill side) of the air filter housing. Does anyone know if this would be an expensive item to replace?

I wouldn't worry too much about the cost of that hose, I got an OEM for $10 or so. The stuff you should worry about is all the other black hoses, plenum donuts, isolators and injector tubes on the engine, they have a tendency to get brittle and crack as well. I just got done replacing all of them on my 420, lots of little bs parts that add up quickly, the lower half of the upper intake is made entirely of the same black rubber, don't know why they did that, all the earlier engines were aluminum.

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Chas

Had a 380SL, 450SL, 380SEL, 420SEL, 500SEL

Got a Euro 500SEC right now.

that is a breather hose P/N B2010-73017 in Fastlane - about $12