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Old 06-05-2017, 10:22 AM
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carreraaficionado
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Default 964 tail pipe smoking oil

I recently acquired another project. I bought a 1991 Porsche 911 with 142k miles. I hope someone here can help me out. I'll give you the "knowns" and hopefully the forum will return some suggestions.

*car has been sitting at a repair shop for almost 2 years with no work being done to it.

*After putting a battery in the car (and checking fluid levels), I attempted to crank the car. Car cranked but smoked from tail pipe almost immediately and never stopped smoking until the car was turned off.

*checked oil level and it is good. (not over filled)

I put the car on my lift...

*Bottom of engine (exhaust manifolds, engine case) coated in oil.

*pressure washed bottom of car and removed all grime and oil.

Due to the amount of white smoke coming from the tail pipe, I don't immediately suspect valve guides as being the cause.

*I removed the intake runners and found a significant amount of oil in the lower (cross pipe where the butterfly is located) of the intake.

*I cleaned out oil from the intake and intake runners, reassembled, and started car. Car DID NOT SMOKE, and I let the car run for about 5 minutes. Smoke started to come from the tail pipe just as it did the first time I started the car, gradually becoming thicker. engine progressively ran worse with increased amount of smoke.

*I removed the 1" and 1/2" rubber lines that come from the oil tank but still had smoke coming from the exhaust.

*I removed all 6 upper intake manifolds and found oil between the head and o-ring on one of the manifolds.

I have not done a compression check or leak down check on each cylinder yet, but plan to this afternoon. I'm beginning to fear it could be worn piston rings allowing oil to get into the combustion chamber.

I try to remain optimistic and hope that because the car has sat for almost 2 years, that the rings are not seated good causing the oil to get by. Any suggestions would be greatly appreciated. I'm going to do a compression check today, but after that i'm at a "stand still" until I get the intake O-rings, but after I put them in, what next?

Should I drive the car for about 15 minutes and see if the smoke subsides?
What's the risk of hurting the motor?
Would letting it idle for any particular amount of time yield any results?
Has anyone had any experience with this problem before?
Not excited about (or apposed to) replacing rings on a piston. but would prefer not to.

Hoping the forum gives me some hope! Thanks

KP
Old 06-05-2017, 10:59 AM
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Rocket Rob
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If the engine was sitting for a long time, some oil could have gotten past the rings and into the combustion area. When I store my cars for the winter, they will smoke for a bit on start up. Have you driven the car? I would take it for an easy drive, staying near home or your mechanic in case there are problems. If you are lucky, the smoking goes away. If not, then you need to investigate further.
Old 06-05-2017, 10:59 AM
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HDA
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I am not an experienced rennlister/porsche owner but if I were in you I would consider 3 options:

1) Engine out and top end/ engine rebuild.

2) Drive it as it is until something major breaks (it will). More expensive engine rebuild.

3) Flip it!

Chasing the "oil smoke" as it seems you are doing may be an endless process, not necessarily coming to an end. After all it's a 26 years old car with many miles.

Why has it been sitting for 2 years? Maybe your engine problem lies in that answer.

Good luck!
Old 06-05-2017, 11:09 AM
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mystert
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Did you check the oil with the car at operating temperature with the oil thermostat open? Checking the oil on these cars is different that "normal" cars. If you just cranked it, saw it smoke, then checked the oil, I would assume you didn't let it warm up enough to properly check the oil level. Mine takes more than 10 minutes just idling in my driveway to warm up to the proper temp. Oil temp gauge horizontal. Sounds like there is a lot of oil in there to burn out and it will take some time.
Old 06-05-2017, 11:29 AM
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rkwfxd
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Serious question,

Will worn rings allow oil to flow backwards and upwards against the stream of intake air/fuel mixture into the intake runners?

That doesn't seem reasonable to me but I don't know. Over filling the oil sump/tank and having it vent into the intake runners seems reasonable. But again, I don't know.
Old 06-05-2017, 12:57 PM
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carreraaficionado
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Rocket Rob:
when I took the air breather, air flow meter, off the car (where I could see into the rubber cylinder on the rear of the intake where I could see a butterfly flap, I was able to see evidence of oil sitting there for a while(shiny stuff was stained dark at the low spots).

Driven the car from the trailer to a shop lift, 100 feet max. but I did allow it to run for about 15 minutes at a time, several times on Friday. Pretty sure I was up to temp. In fact oil was very hot. Before further troubleshooting, I heard sizzling coming from the back right corner (passenger front direction)of the engine. Ultimately found a bad o-ring on that cylinder's intake manifold.

Cadrega:
trying to avoid a top end rebuild. Not against the idea and it might be necessary.
I would drive it as is, but it smokes like a locomotive! very comparable to an industrial mosquito killer! Insane amount of smoke.
I picked the car up for a really good deal, and I do plan to flip it. But I plan to correct every issue on the car first. I've owned about 6 911's, and they are reliable cars, this is the first one I've had to go into (other than valve adjustments).


mystert:
Agreed, there is a lot of oil in there that is burning. Wish I knew I was burning it off, and not just feeding the fire. I considered I might have been overfilled. I even drained about 2 quarts to see if that helped. I got the level so low on the dipstick, it was barely within the spec.


rkwfxd:
No, I don't think that worn rings will allow oil to flow backwards and upwards against the stream of intake air/fuel mixture into the intake runners. And with the amount of oil in the intake that just doesn't seem at all plausible.
There are 2 hoses that come directly from the oil tank/reservoir in the finder. one hose is about 1/2 inch thick there is a restriction in the pipe directly at the oil tank. the restriction is about 1/16th of an inch wide.
the other hose that goes to the intake is about 1 inch thick and connects to the rubbery/plastic part of the back of the intake.
I can only guess that oil/oil mist is coming from this tube, but I really don't know.


Nervous about driving it. as more oil flows through the combustion chamber, the more oil get's on the sparkplugs and im sure driving it anywhere would end me up broke down on the side of the road with wet sparkplugs. Not sure what to do
Old 06-06-2017, 07:51 AM
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Spoke with an independent Porsche mechanic yesterday and he suggested to drive it. Said it is most likely oil in the exhaust from sitting for a number of years and oil getting past the piston rings and sitting in the exhaust manifold. He said that the car probably will need to be run for a few days and run with a load to burn all the oil out of the exhaust. I'll keep adding to the post as I continue to troubleshoot the leak.
Old 06-07-2017, 02:01 AM
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Just 100% double check the tank is not over filled. check when HOT. Keep it at 50% of dip stick no more.
Old 06-07-2017, 10:09 AM
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Originally Posted by Rocket Rob
If the engine was sitting for a long time, some oil could have gotten past the rings and into the combustion area. When I store my cars for the winter, they will smoke for a bit on start up...
Bingo.

Originally Posted by Cadrega
I am not an experienced rennlister/porsche owner but if I were in you I would consider 3 options:

1) Engine out and top end/ engine rebuild.

2) Drive it as it is until something major breaks (it will). More expensive engine rebuild.

3) Flip it!

Chasing the "oil smoke" as it seems you are doing may be an endless process, not necessarily coming to an end. After all it's a 26 years old car with many miles.

Why has it been sitting for 2 years? Maybe your engine problem lies in that answer.

Good luck!
You can tell you are new to 964s. They freak all the newbies out. (not a negative bro!)
Oil lines everywhere, and an engine bay stuffed to the max with various components. It's intimidating and you wonder if you made the right decision? I looked under the car (for oil drips and fallen parts) for a the first two years that I owned the car. I worried about a $20,000 rebuild almost everyday for years. Slowly but surely you learn how awesome and robust these cars are.

The worrying was taking away from the enjoyment of the car, and honestly, it felt a bit disrespectful to the car. I'll just deal with the $20,000 rebuild when the time comes...
(I have 10 years and 50,000+ glorious miles on a resealed engine)


Originally Posted by mystert
Did you check the oil with the car at operating temperature with the oil thermostat open? Checking the oil on these cars is different that "normal" cars. If you just cranked it, saw it smoke, then checked the oil, I would assume you didn't let it warm up enough to properly check the oil level. Mine takes more than 10 minutes just idling in my driveway to warm up to the proper temp. Oil temp gauge horizontal. Sounds like there is a lot of oil in there to burn out and it will take some time.
+1

Originally Posted by carreraaficionado
Spoke with an independent Porsche mechanic yesterday and he suggested to drive it. Said it is most likely oil in the exhaust from sitting for a number of years and oil getting past the piston rings and sitting in the exhaust manifold. He said that the car probably will need to be run for a few days and run with a load to burn all the oil out of the exhaust. I'll keep adding to the post as I continue to troubleshoot the leak.
Sounds like a good mechanic, 964s are happy when driven.
Old 06-07-2017, 11:09 AM
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Originally Posted by 911Jetta

You can tell you are new to 964s. They freak all the newbies out. (not a negative bro!)
Oil lines everywhere, and an engine bay stuffed to the max with various components. It's intimidating and you wonder if you made the right decision? I looked under the car (for oil drips and fallen parts) for a the first two years that I owned the car. I worried about a $20,000 rebuild almost everyday for years. Slowly but surely you learn how awesome and robust these cars are.
LOL I'm going through this now but adjusting.
Old 06-07-2017, 12:58 PM
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Thanks so far for the input, thoughts and advice. As of yesterday afternoon, I dropped one side of the exhaust.... I wish I could show you guys a picture.... I took a flash light and shined into the exhaust and guess what? it looked very shiny and wet. 'No tellin' how much oil is in there, but enough to make the car smoke horribly. Im going to drop the exhaust the rest of the way down (while im waiting on intake O-rings) and try to clean as much oil out of the exhaust as I can. I am starting to believe that most likely the previous owner over-"serviced" the engine oil, and the vacuum from the intake was enough to pull the oil through the combustion chamber all the way to the exhaust.
This is my 2nd 964. I owned one when I was about 26 years old. That car was a beast. It had a few goodies like a power chip, RS flywheel, bigger exhaust. it searched for an idle all the time(due to the flywheel), but I didn't care. That car was very very fast. I'm 40 now, owned a 996, a 993, an 88 cab, and now this. I picked it up as a project and was worried I might have bad rings, but I'm starting to believe I got a really good deal.
Old 06-07-2017, 01:21 PM
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Derek911
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I installed the rothsport check valve due to white smoke at start up after sitting a while and it doesn't smoke anymore. My car can sit all winter, crank it up and no smoke. That wasn't the case prior to the check valve.

One source, not the only source, of smoke could be oil from the tank seeking to level itself out and filling the crank. The check valve will stop this... Especially if you park on a hill or uneven ground. Rings should stop the oil in the first place, but if they are worn a bit then seepage into the cylinder can occur, thus smoke on start up. There are multiple sources of smoke, this is just one. (Let the debate begin.. Lol)

Very easy install, you can use the existing hose or install a new hose. The hose must be cut and the check valve installed in the middle. Do a search, the check valve has been debated already. But I personally did notice a big difference, which probably means I need rings in the coming years.

Some think it is too expensive for a simple check valve, some even sourced other check valves at considerably cheaper prices, but considering how important oil pressure and flow is to our cars, this is one area I didn't want to skimp on and experiment with. Rothsport is a very reputable company when it comes to Porsche, so if it's good for them, it's good for me. The quality of product is top notch.

http://www.rothsport.com/Products/En...eck-Valves.htm

Last edited by Derek911; 06-07-2017 at 01:50 PM.
Old 06-09-2017, 11:27 AM
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UPDATE: So Wednesday and Thursday after work I reassembled the intake and fuel system. While I had the intake off, I took the time to remove the fan shroud from the top of the motor enough to clean the top side of the crank case and heads and removed some leafs, pine straw, and dirt. I replaced upper intake manifold gaskets. I am not a perfectionist, but a little "clean as you go" attitude should be used from time to time on these cars.

I shined the flashlight into the exhaust of the car and could see it was shiny on the inside. So yesterday, I also dropped the muffler from the car. I rested the tip of the muffler in an oil drain pan and collected a few ounces of oil. I then used a concoction of "purple stuff", dawn dish soap, and water and poured it into the exhaust pipe of the muffler. I jostled it and let it soak in the concoction for a little bit and then drained it out. I did this twice.

While I was letting the muffler soak in the cleaner, I cranked the car. NO SMOKE. The car cranked with no problem, idled smoothly, and showed no evidence of smoke. I let the car run for about 20 to 30 minutes while on the lift. No smoke was evident at the exhaust.

I turned off the engine, and reconnected my muffler, and ductwork. I cranked the car up and let it idle on the lift. The car did smoke some after it was started, but im 100% confident that it is residual oil left in the muffler. I plan to drive the car this weekend to burn out the remainder in the muffler.

This afternoon, I have to reconnect the air conditioner, and electric cooling fan on the motor. But I'm calling this fixed.

Derek911, that's a very expensive check valve. $300 might be a little rich for my budget. Im sure it is a great product, but before I consider purchasing one, I am going to test drive aver the next few days and see if the smoke clears out. It looks as though the advantage of the check valve would be for cars that sit for extended periods of time. I bought the car for a great deal, and plan to sell it at the end of summer. Between now, and the end of summer, Im aiming to drive it like I stole it.

On a side note, I am replacing the D90 wheels with Speedline insprired wheels, also replaced all 3 lights on the back of the car. The interior is very clean beige leather, and the exterior is amethyst pearl (Purple).
Old 06-09-2017, 01:04 PM
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Originally Posted by 911Jetta
You can tell you are new to 964s. They freak all the newbies out. (not a negative bro!)
Oil lines everywhere, and an engine bay stuffed to the max with various components. It's intimidating and you wonder if you made the right decision? I looked under the car (for oil drips and fallen parts) for a the first two years that I owned the car. I worried about a $20,000 rebuild almost everyday for years. Slowly but surely you learn how awesome and robust these cars are.

The worrying was taking away from the enjoyment of the car, and honestly, it felt a bit disrespectful to the car. I'll just deal with the $20,000 rebuild when the time comes...
(I have 10 years and 50,000+ glorious miles on a resealed engine)
I am driving mine as it could explode in million of pieces anytime.
Reminds me a lot of when I had a 93 RX-7...
Old 06-09-2017, 01:07 PM
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Originally Posted by carreraaficionado
UPDATE: So Wednesday and Thursday after work I reassembled the intake and fuel system. While I had the intake off, I took the time to remove the fan shroud from the top of the motor enough to clean the top side of the crank case and heads and removed some leafs, pine straw, and dirt. I replaced upper intake manifold gaskets. I am not a perfectionist, but a little "clean as you go" attitude should be used from time to time on these cars.

I shined the flashlight into the exhaust of the car and could see it was shiny on the inside. So yesterday, I also dropped the muffler from the car. I rested the tip of the muffler in an oil drain pan and collected a few ounces of oil. I then used a concoction of "purple stuff", dawn dish soap, and water and poured it into the exhaust pipe of the muffler. I jostled it and let it soak in the concoction for a little bit and then drained it out. I did this twice.

While I was letting the muffler soak in the cleaner, I cranked the car. NO SMOKE. The car cranked with no problem, idled smoothly, and showed no evidence of smoke. I let the car run for about 20 to 30 minutes while on the lift. No smoke was evident at the exhaust.

I turned off the engine, and reconnected my muffler, and ductwork. I cranked the car up and let it idle on the lift. The car did smoke some after it was started, but im 100% confident that it is residual oil left in the muffler. I plan to drive the car this weekend to burn out the remainder in the muffler.

This afternoon, I have to reconnect the air conditioner, and electric cooling fan on the motor. But I'm calling this fixed.

Derek911, that's a very expensive check valve. $300 might be a little rich for my budget. Im sure it is a great product, but before I consider purchasing one, I am going to test drive aver the next few days and see if the smoke clears out. It looks as though the advantage of the check valve would be for cars that sit for extended periods of time. I bought the car for a great deal, and plan to sell it at the end of summer. Between now, and the end of summer, Im aiming to drive it like I stole it.

On a side note, I am replacing the D90 wheels with Speedline insprired wheels, also replaced all 3 lights on the back of the car. The interior is very clean beige leather, and the exterior is amethyst pearl (Purple).
Wow that's great to hear! I am happy for you. Now you gotta post some pictures! I love that color on a 964!


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