A few questions...w124
 

I went through with replacing my OVP today for a hot start issue I've been having. I'm not sure if the issue got fixed or not since it's difficult to recreate consistently but I guess time will tell.

In the meantime, I ran into a couple of surprises along the way.

1. On the driver's side, infront of the wheel well, there looks to be a rubber plug. I also noticed its a constant area where a little bit of water pools up. Seems to me that it should be a drain hole, but after cleaning things out the rubber plug is solid. Is it supposed to be a drain hole? Seems like a good candidate for rust to start. (picture DSC_0407.jpg)


2. The broken plastic clip was used to hold a bundle of wires to a screw. Since it is broken I'm not sure it is doing its job. Should I replace it? What does it do? (picture DSC_0426.jpg, DSC_0427.jpg)

3. There looks to be quite a bit of surface rust on the metal panel that separates the engine area from the battery / electrics area on the passenger side. Should I be concerned about this? (picture DSC_0429.jpg)

I had an '87 124 that had some rust around that area behind the L headlamp.

1) I believe that the 20 mm rubber expansion plug behind the L headlight covers what was actually a paint run-off hole, but you're right that water accumulates there. In my 1988 260E, I pulled the rubber plug out to let the puddle of water drain after washing one day and the plug tore apart from age. As it was the original plug, the underside was completely coated with the PVC rust protection sprayed on the undercarriage at the factory; that made it rigid and brittle. The replacement part # is 113-987-00-44. Now when I wash the car, I just pop out the plug, let it drain, wipe up around the area (particularly the 0.2 ohm resistor for the aux fan) and reinsert the plug.

2) I can't identify these pieces from the photos, and you don't say where they are located in the engine compartment.

3) As for the surface rust behind the battery, I'm not sure what metal area that could be, b/c there should be just the plastic electronics cover there to separate the battery from the relays. It appears that at some point that metal panel was scuffed up and developed surface rust from ambient moisture. In any case, that rust looks so superficial that after 21 years I don't suppose it's going to be a problem now. I'd be inclined to just clean it up as best as possible, put a heavy coat of carnauba on the area and keep it wiped dry after car washes. That's not going to undo the rust, but it'll help keep it under control. Of course, if you're really worried about it, a permanent solution is obviously possible. Take it to a body shop for rust treatment.

I've found that the area behind the inner firewall, including the battery area, the area around the brake booster, under the blower, and around the electronics tends to collect leaves and other debris which can/will hold moisture. I clean twice/year including vacuuming under the blower and removing the battery tray.

Ah ok thanks for clearing that up since when I was trying to figure out what the plug was I accidentally punched a hole through the PVC coating. I will make sure to inspect the edges of the hole in the metal and cover it up with silicone or something so I can take the plug in / out without wearing out the area!

The plastic part holds the bundle of wires that runs under the battery plate.

At first I couldn't figure out if it was surface rust or another colour primer, but it definitely looked like surface rust. It came right off with light sanding and I just primed it and painted with heat resistant spray paint.

It absolutely does. I found a nice small puddle of water right under the battery and under the battery plate. There were also leaves / etc which if they start decomposing and get in the right areas will cause rust. I already took the blower motor out (to lube it but starting to squeak again so I will just replace it this month) and cleaned out the area. Same with the battery area. Slowly but surely I'm just cleaning out and replacing various bits and pieces. I'm surprised out clean some of the areas are even after 16 years!