Genuine BMW part 11 78 1 427 639: Guide tube upper part. The number stamped on the part is 11781427639; BMW's catalog files it under the short number 1427639. You will find it on our Engine shelf, under Exhaust gas control systems.
It fits the E36 sedan, coupe, convertible and compact (318i, 318ti, 328i and M3, 1992–1999), with the M44, M52 or S52 engines — and the European-market versions.
BMW draws it on 3 diagrams, among them Catalyst/Lambda Probe (18_0253) and Catalyst/Lambda Probe (18_0259). It weighs about 23 g (under 0.1 lb).
We have not had one on the shelf yet. Request it and we will tell you when one comes off a car.