If your EGR System has mysteriously “disappeared,” you’ve probably been searching for a reliable method of plugging the intake manifold fittings.
Metric cap nuts are hard to find in the States. Contrary to popular belief, the large nuts with the holes for the tubing are not stainless steel and can be welded — it’s the tubing that is stainless. That’s one fix, but you’ll need an arc welder or a shop to do it for you.
Another fix is filling in the hole with 2-stage epoxy by taping over it, then filling up the inside with epoxy just to the point where the threads begin. Trouble is, epoxy may crack with constant thermal expansion and contraction, shock, vibration, etc. A case in point is the widespread failure of early 530i intake plenum chamber seams.
There is a simple and inexpensive fix.
Obtain two M10x1 bolts (that’s 10mm in diameter and 1-mm thread pitch, folks!) Try to get them 12mm long or something less than that. If necessary, cut to length. Remove the fittings that protrude from the intake manifolds with a 19mm wrench, then replace with your new bolts. Be sure to use a copper gasket ring on each or a couple of drops of LOC-TITE on the threads to ensure a good seal.
If you care to order factory parts for this application, they are: Plug Screw M10x1 P/N 0711 9 919112 and Seal Ring 10 x 13.5 P/N 0711 9 963 073.
Author: Stan Simm