356 T5 B tachometer cable

[Harry Mielonen]

A cable for tachometer was replaced in my 356 T5 B. Immediately after the replacement, the tachometer went out of order .. spinning around like a grazy. The cable was disconnected and oil was leaking through the upper end of the cable. When the engine was running, the cable raised the oil. The tachometer was removed and there was oil inside. On the test table, it was found, that the meter works after cleaning.

Apparently, some gasket is incorrectly installed and the oil travels along the cable to the tachometer. Can someone advise what has failed in the installation?

[Martin Benade]

I’d guess the miniature oil seal on the oil pump that the pump’s drive passes through must be bad. It could be backwards too but probably would still seal well enough.

[Art Caputo]

I had the same thing happen with my T5. While the seal at the cable fitting at the oil pump was present and OK, the small metal washer that rides on top of the seal was missing. Installed the washing and the problem was solved. I’d also check the integrity of the seal as well. Diagram below.
The tachometer did have to be sent out for repair.

[Harry Mielonen]

Thanks for the good advise and we will check the details shown in the picture. I also noticed similar comments on the forum .. the site is really very helpful.

[Martin Benade]

Does the washer keep something from interfering with the seal?

[Art Caputo]

The washer appears to compress the surface of the slightly raised seal when the tachometer cable nut is tightened. This forms the oil seal that keeps the oil from following the tachometer cable. The cable should be lightly greased before reinserting it into the cable housing.