993 white smoke ALOT on startup

[wesleyc]

If I let my car set for a over a week. It smokes like crazy for about five minutes out of both exhaust. I’ve had the car for about 12 years and it’s always smoked a bit after a extended park. But smoke has always stopped after less than a minute. Which is from what I’ve read normal. My question is. Should I be concerned with this massive increase in mosquito killing? After The smoke stops and I drive the smoke totally stops until another extended park. Car has over 140k and I use mobil1 15-50. Tia for any information.

[Kein_Ersatz]

Concern, yes. Not normal. Need to find source of oil finding its way into combustion (Valves, Rings, gaskets, intake [overfill], etc). Assume it is NA and not a Turbo. Longterm will foul plugs, cats, etc, and make a mess on the rear bumper. Notice any significant oil use on the dip stick?

Given a sudden increase on both sides, thinking a common source like intake, but that is then asks why the "push" of oil into the intake (back to rings or gaskets).

[AOW162435]

Do you change your own oil or let a shop do it? The stories of shops overfilling these cars are endless.



Andreas

[wesleyc]

Originally Posted by Kein_Ersatz

Concern, yes. Not normal. Need to find source of oil finding its way into combustion (Valves, Rings, gaskets, intake [overfill], etc). Assume it is NA and not a Turbo. Longterm will foul plugs, cats, etc, and make a mess on the rear bumper. Notice any significant oil use on the dip stick?

Given a sudden increase on both sides, thinking a common source like intake, but that is then asks why the "push" of oil into the intake (back to rings or gaskets).

Yes. It’s a NA. Not a lot of oil usage. “Rings and gaskets “ that sounds like serious work and money. Thanks for responding! I’ll be checking out how much and how intensive the job is.

[Cobalt]

Overfilled oil will cause excessive oil burning.

Rothsport makes a device that supposedly will prevent oil from draining back into the system and prevents smoke on startup. I would check to see the cause first but might be worth looking into.

[wesleyc]

Originally Posted by AOW162435

Do you change your own oil or let a shop do it? The stories of shops overfilling these cars are endless.



Andreas

Thank you for responding Andreas! I always change my own oil and am careful not to overfill. Kein mentioned “rings and gaskets “ that sounds serious. I’ve done a engine drop for a clutch and reseal myself a few years back. I’m afraid doing internal work on the engine might be above my skillset. Living in rural Oklahoma has it’s setbacks when looking for a mechanic for this engine. I’ll find the job description and study a bit… perhaps sacrifice a chicken to the Porsche gods for good luck 😁

[wesleyc]

Originally Posted by Cobalt

Overfilled oil will cause excessive oil burning.

Rothsport makes a device that supposedly will prevent oil from draining back into the system and prevents smoke on startup. I would check to see the cause first but might be worth looking into.

Thanks for input. I just found the check valve you are speaking of. $300! It won’t fix the actual issue internally but would sure save some plugs and appease my neighbors for now.

[wesleyc]

I just started it up after six days of setting and no smoke? I guess it takes two or three weeks of non start that it smokes bad. I did just order the rothsport check valve.

[Kein_Ersatz]

Well if it is oil finding its way into the intake (smoke both sides), then that would be more a factor of how long it was drivers more than how long it sat.

The fact that it has gone away, if 6 days sitting, says more to me of oil in intake not from rings/gasket pressure pushing it there but from some other occasional problem, like overfill. I know you say it was not over filled, but symptoms... Hold off on putting in Rothsport valve until the smoking returns, otherwise you are masking the problem.

Is the 993 ever parked on un-level / very leaning ground that could cause oil to migrate when parked?

[wesleyc]

Originally Posted by Kein_Ersatz

Well if it is oil finding its way into the intake (smoke both sides), then that would be more a factor of how long it was drivers more than how long it sat.

The fact that it has gone away, if 6 days sitting, says more to me of oil in intake not from rings/gasket pressure pushing it there but from some other occasional problem, like overfill. I know you say it was not over filled, but symptoms... Hold off on putting in Rothsport valve until the smoking returns, otherwise you are masking the problem.

Is the 993 ever parked on un-level / very leaning ground that could cause oil to migrate when parked?

Thanks for information. It’s always parked on level ground. Perhaps your right about the oil. I’m always careful to not overfill..but I’ve been known to have a brain fart. It’ll take some self discipline to not put on a $300 check valve but I’ll try.

[p911dad]

These cars are sensitive to being overfilled, and by overfilled I mean when measuring oil on a running engine at operating temperature a level of higher that the 1/2 mark on the dipstick is too high and will lead to oil draining back down into the cylinders at rest (or leak out of the bottom of the the varioram intake manifold all over the top of the engine). I keep mine at the 1/3 mark. Remember, the 993 carries about 12 total quarts of oil in its system and it is only about 1 quart or a little more from bottom to top on the dipstick. You have lots of oil even at the bottom of the dipstick (remember hot engine).

[wesleyc]

Originally Posted by p911dad

These cars are sensitive to being overfilled, and by overfilled I mean when measuring oil on a running engine at operating temperature a level of higher that the 1/2 mark on the dipstick is too high and will lead to oil draining back down into the cylinders at rest (or leak out of the bottom of the the varioram intake manifold all over the top of the engine). I keep mine at the 1/3 mark. Remember, the 993 carries about 12 total quarts of oil in its system and it is only about 1 quart or a little more from bottom to top on the dipstick. You have lots of oil even at the bottom of the dipstick (remember hot engine).

Thanks for information. I cannot get quite 11 quarts in before showing it to be full. I’ll take your advice and go for the 1/3 mark and see how that works.

[p911dad]

Wesley, by 12 quarts I am also including the oil cooler radiator and all the oil lines, both filters, and the engine sump (tiny) and the saddle tank which holds by far the most of the 12 quarts. I should have been more clear that you can only actually replace about 9 quarts at an oil change, depending on if you change out both filters or neither filter (some guys only change filters every other oil change). I change oil once per year (our 993 doesn't get a lot of use) and the filters every other time. That small filter is a real pain to get to.
So after you drained the saddle tank and the engine case and changed the filters, add no more than 9 quarts. Start up, watch for good oil pressure on the gauge. Ignore the oil level gauge (they are generally unreliable) and let the engine get up to operating temp (temp gauge pointer at 8 or 9 o'clock position). Making sure you are on level ground check the dipstick while the engine is running. In my opinion (after 3 air cooled 911's over 30 years) if you see oil at the halfway point or slightly below the marked area on the dipstick you are good to go. If only at the bottom of the dipstick add no more than 1/3 or so quart and recheck the level on the dipstick and maybe then a bit more to get to the desired level. Important: the oil must be warmed up and the engine must be running! Oil expands as it is heated and if you do this with a cold non-running engine you will overfill it. (Also this is the reason to only check the oil level on a warmed running engine, if it is cold you will think you need to add oil when you really don't need to).

[wesleyc]

Originally Posted by p911dad

Wesley, by 12 quarts I am also including the oil cooler radiator and all the oil lines, both filters, and the engine sump (tiny) and the saddle tank which holds by far the most of the 12 quarts. I should have been more clear that you can only actually replace about 9 quarts at an oil change, depending on if you change out both filters or neither filter (some guys only change filters every other oil change). I change oil once per year (our 993 doesn't get a lot of use) and the filters every other time. That small filter is a real pain to get to.
So after you drained the saddle tank and the engine case and changed the filters, add no more than 9 quarts. Start up, watch for good oil pressure on the gauge. Ignore the oil level gauge (they are generally unreliable) and let the engine get up to operating temp (temp gauge pointer at 8 or 9 o'clock position). Making sure you are on level ground check the dipstick while the engine is running. In my opinion (after 3 air cooled 911's over 30 years) if you see oil at the halfway point or slightly below the marked area on the dipstick you are good to go. If only at the bottom of the dipstick add no more than 1/3 or so quart and recheck the level on the dipstick and maybe then a bit more to get to the desired level. Important: the oil must be warmed up and the engine must be running! Oil expands as it is heated and if you do this with a cold non-running engine you will overfill it. (Also this is the reason to only check the oil level on a warmed running engine, if it is cold you will think you need to add oil when you really don't need to).

Thanks for clarity. I’ve probably seldom drained my oil cooler. I recently have elevated the front of the car a bit to drain the oil from the oil cooling radiator at oil change. And I concur “ filter on the engine is a pain”

[Kein_Ersatz]

Unless you have remove engine / cooling parts to "fully" drain the oil system, 11 QTs on a normal oil change is too much based on my experience. YMMV. Again at this point between 8-10 Qts (fresh) it is more about cooling than lubrication (and thus oil life).
Once you are confident you have the root cause (i.e. oil in intake from possible overfill or not), then add in the preventive valve or catch can for future overfill insurance.

[Kein_Ersatz]

[wesleyc]

Originally Posted by Kein_Ersatz

Unless you have remove engine / cooling parts to "fully" drain the oil system, 11 QTs on a normal oil change is too much based on my experience. YMMV. Again at this point between 8-10 Qts (fresh) it is more about cooling than lubrication (and thus oil life).
Once you are confident you have the root cause (i.e. oil in intake from possible overfill or not), then add in the preventive valve or catch can for future overfill insurance.

That sounds like a good idea. Thanks for all your help!

[hienz]

It happened to my car too. Porsche car sometimes park the valves is at open position so oil can drip out from the open valves. Do not worry. Once you drive it it will all burned up then you will not see any smoke. If after driving it for a while, and you still seeing smoke that might be major engine valve problems.

[wesleyc]

Originally Posted by hienz

It happened to my car too. Porsche car sometimes park the valves is at open position so oil can drip out from the open valves. Do not worry. Once you drive it it will all burned up then you will not see any smoke. If after driving it for a while, and you still seeing smoke that might be major engine valve problems.

Thanks. Perhaps that was it? Or accidental oil overfill. Since my original post I’ve had no smoke on startup. I did a oil change and installed a rothsport check valve. Which made for very expensive oil change.

[Cobalt]

Many years ago we used to have the 11 min rule. If a air-cooled sits for long periods and smokes for less than 11 min and doesn't do it again in the future you were considered OK. If it happens again soon after it is worth further investigation. If it continues to smoke after 11 min also grounds for future investigation. I haven't heard anyone use that in at least 25 years but was a common approach.

My car rarely smokes on startup but occasionally will. Leak down was at 6% on all 6 and compression good so I am not concerned and it happens so infrequently.

Darn I wish I knew you were going the rothsport direction. I should have mentioned I had one I never installed I would have sold you cheap.