Jack Esposito

Yes, that surprised me too switching from 15w-50 to 0w-40 and getting less oil burn. My car doesn't use much oil, I can go a few thousand miles before I have to add any most of the time. I checked it regularly and it just didn't seem go down much for 5000 miles.
During that time period I also found I had a vacuum leak that I fixed. Maybe that helped with using less oil.

Jack

bgiere

0w40 has lower "volatility" than the 15w50...volatility is the oils resistance to "burning" and evaporation. 0w40 is less volatile. viscosity has no correlation to "burning". 0w40 is the correct oil to use in all Porsche engines from 1973 onwards according to the factory...this recommendation supersedes all others.

Jack Esposito

Brant,
Are you saying the 0w40 (lower volatility) has less resisitance to burning (uses more) or has more resistance to burning and therefore uses less oil?

Thanks
Jack

bgiere

hi Jack,

should see less oil usage with 0w40. If there is a mechanical reason for the oil usage, no oil will control it. Worn rings,valve guides,etc. will cause oil consumption and at that stage a rebuild is necessary to bring the engine back to "spec" for consumption.

HK G36C

The damn thing is still smoking and you guys are off on your own talking help!!!!

chris walrod

Is the oil smoke actually coming from the exhaust tip? Or just from that general area?

Porscheologist

Yes the key is if it comes out of the exhaust pipe or not. If it was just spilled oil it will not last long (it will burn off). If its a loose hose or filter it will continue (drip finding its way to exhaust component) If its truly worn rings/valves then It will not go away and I would suggest you go back to the heavier oil and start saving your pennies for a top-end rebuild.

Let us know what you find after you really take a look under the engine. ( I'm sure your engine pan is off so it should be really easy to check for leaks). By the way you may already know this but oil overfill also causes smoke and is quite common.

Jack Esposito

If it wasn't smoking at all before the oil change and is smoking now with nothing else done to the engine, then something about the oil change caused your problem. Either a different brand/type of oil was used causing it to smoke, the oil was over filled and is getting sucked into the engine or a vacuum line isn't right someplace and is causing oil to be sucked into the engine. The car shouldn't just all of a sudden start using/burning oil for no reason.
Is there any chance someone at the shop took your car out for a quick drive without warming it up and damaged something in the engine?

Good Luck
Jack

Jack Esposito

Been doing some more thinking about your smoking problem and maybe figured out what's going on. Seem to recall a PCV valve attached to the oil tank to suck off all the bypass gasses and it puts these gasses back into the engine intake manifold on the right side. Fresh oil would have a lot more volatiles to bake off each time it got hot until you baked them all out over time. So maybe the blue smoke is just the burning off of these volatiles and all you need to do is drive the car a little more till it clears up.

Jack

HK G36C

It is coming from the tip not the general area...and only the right side

bgiere

Overfill is possible...check your air filter for oil residue....have you driven the car for a good distance? take it out for a drive...see if if stops.

Jack Esposito

If oil or volatiles are being sucked through the PCV valve or air filter back into the engine, they will be burned in the engine, and blue smoke will come out the tailpipes. The vacuum line to the PCV valve attachs to the right side of the intake manifold. Any oil sucked through that line will be burned in the right side combustion chambers and the exhaust will be out the right side tailpipe tip. This is done for emission purposes to burn off any gasses created within the engine or oil tank.

Jack