So my 99 C43 has a "sweating" valve cover gasket, mostly on the passenger side of the engine. I have gotten the new gaskets but have a question or two before I put them on.

Does Mercedes require a silicon of any sort prior to putting the new gasket?

In the pic below, there seems to be a portion above the valve cover (circled in red) which to me seems it has its own gasket?

Thanks alot for help

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99 C43
98 S420
99 C230K
01 C240

Good morning, the part circled in red is the PCV chamber and is sealed with 3M 5900 silicone sealer. You may want to replace the screws securing the chambers to the valve covers as the original ones are aluminum. Be sure to clean the valve cover and the chamber cover of all the original sealer and run a small bead of sealer in the groove on the chamber cover and around the bolt holes. The valve cover gasket itself does not need any sealer. If you reuse the aluminum chamber bolts be careful not to over tighten them because they may break.
You should also replace the pcv hoses as they are usually very hard and tend to split upon removal, more so on the left side than the right.
One other thing to watch for is the electrical connectors on the coils tend to break the securing tab on the later style connector ( not sure what year they went to the later style).

Good luck, Robert

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Mercedes Benz Master Tech - Retired

Thank you kindly Robert for the informative reply. I will tackle this soon and see how it goes.

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99 C43
98 S420
99 C230K
01 C240

One more question is, this week I replaced the crank position sensor as the car one night idling in a drive thru (87 degrees was on the gauge) and didn't want to start up until 20 mins later of cooling with the hood open which I read that was the culprit. Haven't driven it yet however it fired up with the new sensor but upon changing it the plastic security tab broke on the connector....now it's fairly secure when pluggedin after (feels like a suction) but I'm worried it might come out?

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99 C43
98 S420
99 C230K
01 C240

If you unplug the sensor again and get the wire up to where you can read the part number off of it you should be able to order the parts from the dealer. Usually most plugs can be taken apart without too much difficulty. I have not taken one of those exact plugs apart so I'm not 100% sure. I'll have to look at one at work tomorrow to see how it comes apart.

Robert.

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Mercedes Benz Master Tech - Retired

Thank You!

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99 C43
98 S420
99 C230K
01 C240

Sure thing, I'm glad I could help.

Robert

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Mercedes Benz Master Tech - Retired

I've seen several cars come through the shop with the tab broken on the wiring harness for the CPS, they seem to stay on without a problem - I've not seen a car with the wire wiggled off yet.