Team -

On the front of the engine that came in the '73 280C, there is a banjo fitting connected to a black plastic hose that runs to the back of the car. The banjo attaches via one of those clever bolts with a hole on each side to a 24mm screw-in plug that goes in the block and also holds the bracket for the timing sensor.

Does anyone know what this is for? It would appear to be some sort of emissions control or vent connecting the crankcase with the vapor control mechanism.

The reason I ask is because the replacement engine came with a "blank" 24mm plug that is less deep than the "banjo plug". I would need to add another washer to get the "banjo plug" to fit. Also, inside the 24mm hole in the new block there is a 12 or 13mm cap nut with a small hole in the center - this is not present in the old block. What does this do?

I ran this by the dealer parts dept. this morning, and their books did not show any detail on this.

TIA

Chuck

Chuck,

I have a similar fitting and hose on the front of the 4.5, and on mine the plastic line had broken. I repaired with rubber vacuum line and asked the same question. The banjo fitting and line are for crankcase ventilation.

Can't help you on the differences between your two engines.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

Chuck,
There was a change way back. They added a 5 bar pressure relief valve to the main oil passage in the block(in addition to the one on the pump). All exchange engines have this. It uses a different closing plug that replaces the one with the vent line in it. The vent line must be relocated from the block to the cylinder head on cars with evaporative emission control w/o a charcoal cannister (like yours). There is a kit, pt#114-010-26-99, to convert the connection. The location for the new connection on the cylinder head is behind the a/c idler pulley bracket (the bolt closest to the passenger side of the car).
There, now you know more than I do about it.
Regards,
Randy D.

Good call Randy! Thanks much.

Chuck

Randy -

The dealer is telling me that this kit is no longer available from MB. What do you suggest as a backup? I now have a spacer to install the bano on the lower block, but is this advisable with the newer arrangement in the block?

Should I remove the relief valve?

TIA

Chuck

Hi Chuck,
You're not supposed to use the old cover plug on the engines with the relief valve. I wouldn't remove the valve, there is usually a reason for changes. The kit was a fitting that would screw into the cylinder head and allow the line to be moved there. Check the engine you have for the fitting or call a salvage yard...it would be rare. Maybe the best solution is to make the old cover plug match the dimensions of the later one. I'll do some checking and see what I can find out.
Randy D.

The 24mm spacer I got would allow me to use the original cover, and mount the banjo in its original location.

I got a rebuilt head from Adsit, and it has a 15mm (approx) threaded hole in the front, looks about right to be behind the AC idler. Is this where the banjo and line need to go?

Thanks

Chuck

That sounds like the one. There should be only one hole that goes through the casting (not into the cooling jacket). It was originally sealed with an 8 mm Allen plug according to the Service Info. The picture I have on the microfiche shows the connection going to the right-most (closest to the passenger side)bolt hole behind the A/C idler bracket as the one. I did find another part number for the "bolt" that is included in the nla kit it's a 110 997 13 30. Try that one and see if it's any good. Apparently the kit had a piece of new line and the bolt.
BTW, the original reason for moving the line was to correct for complaints about oil entering the evaporative emission circuit. Then when they added the relief valve they referred back to the original SI.
Regards,
Randy D.