My 97 850 has an oil vapor smell inside the car when stopped or driving around town with the windows up. I replaced the oil filler cap seal, don't see a leak anywhere. It is not exhaust I smell but oil vapor like a breather outlet. Thanks for the help!

Look at the fuel-pump black seal. If there are traces of petrol/gas, the seal is worn. Replace it with new.

Oh, please dont smoke, while checking this out.
:)

With the engine running, loosen the oil filler cap. Does it make a hiss like you're opening a beer / soda?

If it DOES hiss, does that mean the pump is bad? Or a leaking pump?

Just checking...
:)

If you loosen the oil filler cap and it makes a hissing sound, then the engine is pressurizing internally due to a clog somewhere in the PCV system. When the engine pressurizes like this, it will blow that pressure out of the filler cap, and with that comes vaporized oil which the driver will likely smell. That oil collects on the valve cover, but the section of the valve cover where it accumulates is covered by the plate that covers the spark plug wires. You can look at the engine and not see any oil, but as soon as you pull that cover off the spark plug wires you will see oil pooling everywhere. It's a mess, and it also adds to the smell of oil in the cabin.

Just one possibility, but a likely one. Given their location, the PCV components don't usually get much attention until there is a problem.

Well, i gave myself some time, to digest what was written here.
:)



Hmmm... I am thinking more like the pressure is escaping from worn or damaged piston rings, to be able to make the hissing sound more audible. At this juncture, i dont think you'd be able to tell if the PCV system is clogged just yet.






Well, yes, assuming that the PCV system is clogged to begin with. Or should we assume all 850s at this age that has not looked at the oil traps, is definitely having a clogged pcv?

While the likelihood is very high (based on as you observed, the rate of people signing in and complaining about similar smoking at the exhaust?), why dont we look to see if there is other areas that is the point of origin?





Based on my experience looking at cars, most of the times, the oil that is left under the valve cover, either:-
1) Comes from the inner parts of the oil-cap (when opened, owner turns it upside down, and oil seeps into the casing well.)
2) PCV hose on top not secured or torn or damaged
3) SOMETIMES, a very bad leak from the camshaft oil seals may also lead to oil accumulating here
4) Outright spill of oil on it...






YES, I agree.
:)