So I did a light engine bay cleaning, and noticed a couple of things:
The water drain was clogged up at the bottom with a lot of water in it. I could wiggle the whole drain housing a bit which caused the water to flow out slowly but the leaves and dirt are still in there. Any ideas on how to clean it? I can't see any obvious way to get it out. What is the electrical part that's attached to the top of the housing? Right next to the fuse box cover on left behind the firewall. Couldn't find a exploded view of the engine bay with that part on it. Mine is missing screws and seems to be replaced. I'm also missing the 2 top bolts of the ac radiator, the 'first' one, vacuuming a gazillion bugs out of it. What size bolts should they be?
Overall I'm happy with a couple hours of work and it's a satisfying job. Next up interior led upgrade, ordering the 2 air intake hoses and a washer fluid tank if I can find a new one (already can tell it's gonna be a pain to properly clean it).
The black plastic grille just snaps out of the funnel housing. That is the HVAC plenum, and the drain at the bottom has killed quite a few W220 models. If you let the water build up in the plenum, it will flow thru the firewall and under the carpet. There will be NO sign of a water leak inside the car! The water will be totally hidden under the carpet. Once the water is in there, it will flow back in the stamped channels in the floor, causing corrosion and poor electrical connections in some of the major power feeds and fuses. If the water continues to leak into the car, it will flow under the carpets to the rear seat area, where it will cause corrosion and major electrical problems.
At this point, the safest approach will be to remove the carpet and insulation from the passenger floor area, and check for any traces of water or corrosion in or around the electrical connections.
To reemphasize,:
There will be no trace of water until you remove the carpets.
You must not allow the HVAC plenum to collect water. Most folks have removed the small drain valve at the bottom of the plenum, and Mercedes issued a bulletin saying that you should drill a hole in the side of the plenum.
Am I glad I asked! What where they thinking designing it this way, it wasn't a recall item? Not only is the hole to small but under it it has an even smaller 'outlet' in the shape of a whip cream can tip with 'teeth'. So outside parked cars are gonna clog up no matter what. Mine went from super clean (I could see through it) to completely clogged up in less than 6 weeks even with my habit not to park under trees and such.
Thankfully inside everywhere is dry, so glad I got with the program early on. Thx guys!
These are the bolts I'm missing on the front radiator, looking for the size in particular what length they have to be.
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
