oil sight glass

[31310]

There is a wee bit of oil slobber just below the sight glass on my RT. Is this a serious problem or just a sign the o-ring needs to be replaced? Fwiw, have been running synthetic last 25K km.

[greenwald]

There is a wee bit of oil slobber just below the sight glass on my RT. Is this a serious problem or just a sign the o-ring needs to be replaced? Fwiw, have been running synthetic last 25K km.

Doubt that syn is the problem.

More than likely, you need a new sight glass assembly (sometimes, they just fail). Just have it replaced by the dealer at the next oil change.

Good Luck.

[PGlaves]

The sight glass assembly (metal backer, lens, rubber surround) is a simple push fit into the machined hole. It should go together clean and dry. The only thing that holds most of them in is friction. Note: I have been told that some later models now have a machined groove and snap ring. I don't know which models.

If you don't have a snap ring then that oil slobber is a potential serious problem. Once an oil film seeps between the rubber and the metal the oil does what oil does best. Lubricate and reduce friction. So some day, usually on a cold startup when the rubber is stiffest, poof - out it pops. If you notice it right away all you lose is some oil, and you get to try to get the oil off your boot and pantleg. If you don't notice you lose an engine, and maybe run the rear tire through your own oil slick and crash.

My rule is as soon as there is seepage the sight glass assembly gets replaced. Drain the oil first for obvious reasons. Push the new one in (clean and dry) as far as you can with your thumbs and tap it in the rest of the way with an appropriately sized socket as a driver resting only against the rubber surround.

[31310]

Thanks for the info Paul, looked at it again after your post and it does have a snap ring. Ordered new parts from the dealer, their fiche does show a snap ring, some of the other online fiches do not show one. At least with a snap ring, one can ride with some confidence the glass will not just blow out.

[deilenberger]

Paul,

I believe ALL the hexheads have the retaining ring. Seems one of those lessons BMW learned from the oilhead engines.

[PGlaves]

Paul,

I believe ALL the hexheads have the retaining ring. Seems one of those lessons BMW learned from the oilhead engines.

Thanks Don, filed in the brain cells (for a little while at least).