Base Gen2 Cayman - Smoke upon startup and Valve guide issue
02-28-2011, 06:09 AM
#16
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Some pictures of the 2.9L engine internals (~15000km):
Head seen from the combustion side. Look at the spark plugs, they all look identical and clean. The exhaust valves are the small ones (smaller circles/heads):
The head gasket looks perfectly fine:
Here you can see the block. From left to right, cylinders #3, #2, #1 and respective pistons (#1 is at the top):
Cylinder #3. Cylinder wall and piston both look normal, no scratches:
Cylinder #2. Cylinder wall and piston both look normal, no scratches:
Another shot of the cylinder #2. #1 looked like this also (i didn't took a picture because at the time i was photographing the #1 piston was at the top):
Head seen from the combustion side. Look at the spark plugs, they all look identical and clean. The exhaust valves are the small ones (smaller circles/heads):
The head gasket looks perfectly fine:
Here you can see the block. From left to right, cylinders #3, #2, #1 and respective pistons (#1 is at the top):
Cylinder #3. Cylinder wall and piston both look normal, no scratches:
Cylinder #2. Cylinder wall and piston both look normal, no scratches:
Another shot of the cylinder #2. #1 looked like this also (i didn't took a picture because at the time i was photographing the #1 piston was at the top):
02-28-2011, 06:37 AM
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Head seen from the valve train side without the camshafts and the lifters:
Camshafts. The one on the top is from the intake side:
Another shot of the camshafts:
Exhaust hydraulic lifters. They all looked fine:
Intake hydraulic lifters and all the oil inlets/outlets needed for the Variocam Plus variable lift to work and for valve lash compensation. They all looked fine:
From the last picture you can clearly see that the lifter has a 'latch' that doesn't allow it to rotate in its bore while the intake valves are being actuated (same for the exhaust lifters).
Camshafts. The one on the top is from the intake side:
Another shot of the camshafts:
Exhaust hydraulic lifters. They all looked fine:
Intake hydraulic lifters and all the oil inlets/outlets needed for the Variocam Plus variable lift to work and for valve lash compensation. They all looked fine:
From the last picture you can clearly see that the lifter has a 'latch' that doesn't allow it to rotate in its bore while the intake valves are being actuated (same for the exhaust lifters).
02-28-2011, 06:39 AM
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Bank #1 exhaust manifold:
If you take a better look at the picture you can see how #1 and #2 exhaust runners (the first two from the left) have some kind of abrasion which is not present inside the runner from cylinder #3. They are not of equal length (or shape) thus i don't know if that abrasion have to do with the exhaust gas flow dynamics through the first two runners (they are more alike) which is different from what happens in the third one. Nevertheless, i find it strange.
If you take a better look at the picture you can see how #1 and #2 exhaust runners (the first two from the left) have some kind of abrasion which is not present inside the runner from cylinder #3. They are not of equal length (or shape) thus i don't know if that abrasion have to do with the exhaust gas flow dynamics through the first two runners (they are more alike) which is different from what happens in the third one. Nevertheless, i find it strange.
02-28-2011, 11:29 AM
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The potential cooling surface area of a cylinder is many times greater than the same potential cooling surface area of the heads. They are more difficult to cool. Most of the area in contact with the burning fuel is valve heads and the spark plug and nearby are the inlet and exhaust ports. There is relatively little room in the heads to flow coolant near aluminium that is directly being heated up by combustion. That's the reason why the valves and the bronze guides so greatly rely on the oil supply not only to lubricate but ALSO to cool them. The oil flow to the guides creates a second heat transfer path from the valve and guide and thus augments the cooling of these components. With sufficient oil flow across the hot valve stem and upper portion of the guide, both of which are exposed in the head, heat is readily transferred from these components to the oil at the same time that it is passing through the cylinder head to be transferred to the coolant flowing through the galleries and, ultimately, to the air across the radiators. It is this additional cooling provided by the oil flow that is of paramount importance. That second heat transfer path mentioned above is successful in providing augmented valve and guide cooling that extends the longevity of those components which receive it.
Loose valve guides means that the valve stem is allowed to rock back and forth inside the guide while it goes up and down causing excessive constant friction between the guide and stem. Side forces on the valve stem caused by changes in valvetrain geometry and direct acting overhead cams contribute this way to guide wear. To make matters worse, you have positive exhaust valve seals on these engines which prevent the guides from receiving much lubrication to start with. In fact, one of the reasons why the smoke is occasional it's because when guide wear exists and the stem rocks back and forth inside the guide, occasionally, these seals are not allowed to conveniently seal and more oil gets past them. Now just imagine what happens when the oil gets thinner due to higher than normal temperatures as a result of less than desirable localized coolant flow rate, the friction between the guide and stem becomes exponentially greater. If the guides are weak enough (too soft, loose tolerances, etc...), air pockets and/or low coolant level may lead to hot spots development in the engine head exhaust area and thus rapid guide wear. Hot weather and agressive driving style will only make it worse.
Now, gen2 base Caymans reportedly have had issues, at least that has been my experience with two base Caymans, with the cooling system not being totally free of what seems to be air pockets from the factory fill up. So much so, that the coolant will be below MIN level during the first few thousand miles if care isn't taken. Low coolant level is obviously dangerous but so are air pockets in the engine cooling path because air pockets tend to build up precisely in the tiny coolant passages where the flow rate tend to be less and the temperatures tend to be higher. The same thing to the low coolant level. Localized steam pockets will form where the coolant flow rates are less and the temperatures are higher - the tiny passages in the heads that cool the exhaust valves and guides.
To understand the extent of the problem look at the following picture where you can see that Porsche engineers had the preoccupation of providing a tiny coolant passage (encircled in red) ONLY to cyl. #1 exhaust valves side (same is valid for cyl. #3) where there is none for the intake valves side, because temperature is, for obvious reasons, much higher in the exhaust side area:
Loose valve guides means that the valve stem is allowed to rock back and forth inside the guide while it goes up and down causing excessive constant friction between the guide and stem. Side forces on the valve stem caused by changes in valvetrain geometry and direct acting overhead cams contribute this way to guide wear. To make matters worse, you have positive exhaust valve seals on these engines which prevent the guides from receiving much lubrication to start with. In fact, one of the reasons why the smoke is occasional it's because when guide wear exists and the stem rocks back and forth inside the guide, occasionally, these seals are not allowed to conveniently seal and more oil gets past them. Now just imagine what happens when the oil gets thinner due to higher than normal temperatures as a result of less than desirable localized coolant flow rate, the friction between the guide and stem becomes exponentially greater. If the guides are weak enough (too soft, loose tolerances, etc...), air pockets and/or low coolant level may lead to hot spots development in the engine head exhaust area and thus rapid guide wear. Hot weather and agressive driving style will only make it worse.
Now, gen2 base Caymans reportedly have had issues, at least that has been my experience with two base Caymans, with the cooling system not being totally free of what seems to be air pockets from the factory fill up. So much so, that the coolant will be below MIN level during the first few thousand miles if care isn't taken. Low coolant level is obviously dangerous but so are air pockets in the engine cooling path because air pockets tend to build up precisely in the tiny coolant passages where the flow rate tend to be less and the temperatures tend to be higher. The same thing to the low coolant level. Localized steam pockets will form where the coolant flow rates are less and the temperatures are higher - the tiny passages in the heads that cool the exhaust valves and guides.
To understand the extent of the problem look at the following picture where you can see that Porsche engineers had the preoccupation of providing a tiny coolant passage (encircled in red) ONLY to cyl. #1 exhaust valves side (same is valid for cyl. #3) where there is none for the intake valves side, because temperature is, for obvious reasons, much higher in the exhaust side area:
02-28-2011, 04:03 PM
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I say drive it hard until it blows up or sell it. Don't waste your time waiting for Porsche to fix something that you think is a problem but they don't. Life's too short. Get out and drive. :-)
02-28-2011, 04:12 PM
#21
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I'm going to tell you your measurement technique is flawed.
All you are measuring is the amount of play or movement the valve stem has at its outer end. This is not a reliable indicator (no pun) of the actual clearance, at least not without some trig.
Really, the valve stem's outer diameter wants to be measured with a precision and accurate outside micrometer, at least one that measures in 'tenths' (machinist's term), that is 10thousandths (0.0001) of an inch, and even better would be a micrometer that had a resolution down to 0.00005". (A general rule is you use a measuring tool that has a precision at least 10 times that of the smallest dimension you are trying to measure. Thus if you are working at the 0.001" level, the micrometer should be one capable of measuring down to 0.0001". If you want to know something's dimension to within 0.0001" you need something that measures down to 0.00001" but these are expensive and found mostly in inspection labs. But micrometers that measure down to 0.00005" are less expensive (though not cheap I bet.... they weren't cheap several decades ago when I used to buy them for my use when I worked as a machinist.)
Then the bore or inner diameter of the valve guide wants to be measured using a precision and accurate dial bore gage. In a pinch one can use a snap bore gage and use the outside micrometer to then determine the valve guides' bore diameter.
The difference between what the valve guide bore's dimension is vs. the valve stem's outside diamter is is double the clearance.
Just picking some numbers out of the air, say the valve stem measured 0.3750" and the valve guide bore measures 0.3765". The clearance is 0.0015" divided by 2 or 0.00075".
Sincerely,
Macster.
All you are measuring is the amount of play or movement the valve stem has at its outer end. This is not a reliable indicator (no pun) of the actual clearance, at least not without some trig.
Really, the valve stem's outer diameter wants to be measured with a precision and accurate outside micrometer, at least one that measures in 'tenths' (machinist's term), that is 10thousandths (0.0001) of an inch, and even better would be a micrometer that had a resolution down to 0.00005". (A general rule is you use a measuring tool that has a precision at least 10 times that of the smallest dimension you are trying to measure. Thus if you are working at the 0.001" level, the micrometer should be one capable of measuring down to 0.0001". If you want to know something's dimension to within 0.0001" you need something that measures down to 0.00001" but these are expensive and found mostly in inspection labs. But micrometers that measure down to 0.00005" are less expensive (though not cheap I bet.... they weren't cheap several decades ago when I used to buy them for my use when I worked as a machinist.)
Then the bore or inner diameter of the valve guide wants to be measured using a precision and accurate dial bore gage. In a pinch one can use a snap bore gage and use the outside micrometer to then determine the valve guides' bore diameter.
The difference between what the valve guide bore's dimension is vs. the valve stem's outside diamter is is double the clearance.
Just picking some numbers out of the air, say the valve stem measured 0.3750" and the valve guide bore measures 0.3765". The clearance is 0.0015" divided by 2 or 0.00075".
Sincerely,
Macster.
02-28-2011, 07:11 PM
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Don't like garge queens.
02-28-2011, 07:35 PM
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Macster,
A dial gauge measurement, althought not the most accurate, is suggested by a lot of brands to access the valve guides condition, Porsche included.
Planet-9 gave me the value of 0.25mm, allegedly supplied by Porsche, for a dial gauge test just like the one i performed. For a value of that magnitude or down to 0.05mm and even lower, 0.01mm of resolution on the dial gauge is quite enough.
Eventually, i will take the head to a machinist and i'll know for sure if any of the exhaust guides is worn, but before that i'm waiting for the Porsche values (dial gauge test) that you said you could eventually supply me.
Do you think you can get me those values?
A dial gauge measurement, althought not the most accurate, is suggested by a lot of brands to access the valve guides condition, Porsche included.
Planet-9 gave me the value of 0.25mm, allegedly supplied by Porsche, for a dial gauge test just like the one i performed. For a value of that magnitude or down to 0.05mm and even lower, 0.01mm of resolution on the dial gauge is quite enough.
Eventually, i will take the head to a machinist and i'll know for sure if any of the exhaust guides is worn, but before that i'm waiting for the Porsche values (dial gauge test) that you said you could eventually supply me.
Do you think you can get me those values?
02-28-2011, 09:58 PM
#24
Race Director
Well, granted it has been some time since I had my hands inside an engine but I do not recall coming across that measurement technique.
Now, I do recall this techique of giving each valve stem a wiggle with the valve seated ( using hand pressure to hold the valve against its seat ) to at least spot a very loose valve stem/guide fit. The idea is one has a large population of valves to check this way and the one(s) that stand out as having a lot of wiggle (make that almost any wiggle at all) were then flagged as being too loose.
One could then measure the clearance as I described earlier or just have the guides replaced, or possibly resurrected by their id's made smaller by the use of a roll tap like tool then reamed to size. Provided the valve stems were not worn this technique resurrected the current guides and the rolling operation left some nice voids that helped provide a better path for oil to the farthest reaches (the area closest to head and furtherest away from the valve seal) of the valve stem/guide.
Anyhow, I prefaced my query with something to the effect if he chose to supply the info or not I would not hold it against him or his employer. The tech I contacted replied something to the effect he thought the interest in that dimension was 'fishy'.
That I heard nothing further from him as of this time tells me I'm not likely to get a reply.
However, I will see if I can find the time to stop by there in the morning and ask him face to face for the info.
If not then I can only use a regular visit to the dealership for something my car needs as an excuse to present the question to him face to face. I do not know when this will happen. I have at least one problem with my Boxster (coils are suspected going bad) but the symptom has not reappeared and believe it or not I'm working on a project that deals with diagnostics touble code queries and the more the merrier. Having a real vehicle (as opposed to an Ecu simulator) with 5 *real* Dtcs at this time is a blessing, and I'm not about to fix the car until I'm through using its a test bed, provided of course the symptoms don't get worse. There was a bit of rough running at the time the misfires occured (after a cold start) but since then the engine has performed flawlessly.
Sincerely,
Macster.
Now, I do recall this techique of giving each valve stem a wiggle with the valve seated ( using hand pressure to hold the valve against its seat ) to at least spot a very loose valve stem/guide fit. The idea is one has a large population of valves to check this way and the one(s) that stand out as having a lot of wiggle (make that almost any wiggle at all) were then flagged as being too loose.
One could then measure the clearance as I described earlier or just have the guides replaced, or possibly resurrected by their id's made smaller by the use of a roll tap like tool then reamed to size. Provided the valve stems were not worn this technique resurrected the current guides and the rolling operation left some nice voids that helped provide a better path for oil to the farthest reaches (the area closest to head and furtherest away from the valve seal) of the valve stem/guide.
Anyhow, I prefaced my query with something to the effect if he chose to supply the info or not I would not hold it against him or his employer. The tech I contacted replied something to the effect he thought the interest in that dimension was 'fishy'.
That I heard nothing further from him as of this time tells me I'm not likely to get a reply.
However, I will see if I can find the time to stop by there in the morning and ask him face to face for the info.
If not then I can only use a regular visit to the dealership for something my car needs as an excuse to present the question to him face to face. I do not know when this will happen. I have at least one problem with my Boxster (coils are suspected going bad) but the symptom has not reappeared and believe it or not I'm working on a project that deals with diagnostics touble code queries and the more the merrier. Having a real vehicle (as opposed to an Ecu simulator) with 5 *real* Dtcs at this time is a blessing, and I'm not about to fix the car until I'm through using its a test bed, provided of course the symptoms don't get worse. There was a bit of rough running at the time the misfires occured (after a cold start) but since then the engine has performed flawlessly.
Sincerely,
Macster.
02-28-2011, 10:34 PM
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Just for the record, bank #1 injectors were disconnected one by one and the ticking noise remained unchanged. Dealer want to replace the bank #1 lifters so i'm going to take the opportunity, although I'm positive that's not a lifter problem, and i'm going to pull the head off again to take it to a machinist. Then, i will have all the measurements and will present them to Porsche.
02-28-2011, 10:52 PM
#26
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As you can see my dealer wasn't lying. Porsche doesn't supply that kind of information. Thank you, anyway. No need to bother anymore.
Just for the record, bank #1 injectors were disconnected one by one and the ticking noise remained unchanged. Dealer want to replace the bank #1 lifters so i'm going to take the opportunity, although I'm positive that's not a lifter problem, and i'm going to pull the head off again to take it to a machinist. Then, i will have all the measurements and will present them to Porsche.
Just for the record, bank #1 injectors were disconnected one by one and the ticking noise remained unchanged. Dealer want to replace the bank #1 lifters so i'm going to take the opportunity, although I'm positive that's not a lifter problem, and i'm going to pull the head off again to take it to a machinist. Then, i will have all the measurements and will present them to Porsche.
What is probably holding him back is the info is buried and he just doesn't want to take the time to search for it. And frankly I am a bit leery of pushing my relationship with him to pressure him for it.
Also, really you should measure the valves and valve guides with a micrometer/bore gage or snap gage. That wiggle test assumes the wear is linear but the valve stems/guides can wear in a non-linear fashion with the wear concentrated, at the valve end, I suspect.
FWIW, a guick search turned up the 964 valve clearances are 0.0011 inches to 0.0022 inches with a wear limit of 0.0059 inches. Remember, that the od of the valve stem and the id of the guide will be such that the differences will twice these amounts. Thus if the valve stem measures 0.375 inches the guide will measure from 0.3772 inches (0.0011 inches clearance) to 0.3794 inches (0.0022 inches clearance). And that wear limit of 0.0059 inches means that when the clearance reaches 0.0029 inches the valve stem/guide are at their wear limits.
As I suspected the clearances are on the order of around a thousandths of an inch or so at the tight end of the clearance and just a couple of thousandths at the loose end of the clearance and are worn out (at their wear limits) a bit beyond that.
Sincerely,
Macster.
03-01-2011, 03:14 PM
#27
Race Director
As you can see my dealer wasn't lying. Porsche doesn't supply that kind of information. Thank you, anyway. No need to bother anymore.
Just for the record, bank #1 injectors were disconnected one by one and the ticking noise remained unchanged. Dealer want to replace the bank #1 lifters so i'm going to take the opportunity, although I'm positive that's not a lifter problem, and i'm going to pull the head off again to take it to a machinist. Then, i will have all the measurements and will present them to Porsche.
Just for the record, bank #1 injectors were disconnected one by one and the ticking noise remained unchanged. Dealer want to replace the bank #1 lifters so i'm going to take the opportunity, although I'm positive that's not a lifter problem, and i'm going to pull the head off again to take it to a machinist. Then, i will have all the measurements and will present them to Porsche.
To put it kindly they think you're crazy. If you had an issue with the engine you should have had it dealt with under warranty. By disassembling the engine you have voided the warranty. (Both techs also expressed some disbelief that you would be able to successfully reassemble the engine properly: Mention was made of special tools being required. I didn't press for details.)
Both said they have seen brand new Porsches smoke upon startup, sometimes quite heavily. New cars get started and run for very short intervals as cars are moved around the new car showroom and new car lot. But the techs said they always note how long the smoking lasts. If it presists, or appears after the car has been driven some and the engine was up to temp when it was shut down, or if the smoking is accompanied by any other abnormal behavior, then the smoking (and other behavior if present) raises a red flag.
I mentioned the 964 valve clearance numbers and they both said those numbers are very close to the valve clearances for the new engines, in fact most Porsche engines. There's no magic involved. The technology and physics at the valve stem/guides are well understood by everyone in the auto industry and a Toyota, a Porsche, and a Ferrari engine are going to have nearly identical callouts of these (and other internal engine component) clearances.
Anyhow, I'm sorry I was not able to obtain the numbers.
But I wish you every bit of good luck in getting the problem (if there is a problem) resolved to your satisfaction and getting the engine back together successfully.
Sincerely,
Macster.
04-17-2011, 06:45 PM
#28
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Update!!!
Last edited by CaymanPower; 05-02-2011 at 11:18 AM.
05-02-2011, 10:38 AM
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I was wrong about the relationship between the ticking noise from cyl. bank #1 and the smoke upon startup that comes from cyl. bank #2. Which is not saying that the problem isn't bad exhaust valve guide(s). And, to show you that a bad exhaust valve guide can allow oil to 'leak' out of an exhaust without never 'seeing' the combustion chamber in a flat boxer engine and hence justify the clean spark plugs, here is some quotes from the 'Pelican Parts' forum:
"Not to raise an alarm, but my 3.2 looked like that with bad valve guides. My symptoms included the smoke as Richard mentioned above. Oil drops into exhaust past exhaust valve guides. Once the car is re-started it blows out the accumulation. Guide condition is not determined by compression or leakdown testing. John Walker needs to offer his opinion as well..."
PLEASE tell me I dont have a problem..(Photo attached) - Pelican Parts Technical BBS
PLEASE tell me I dont have a problem..(Photo attached) - Pelican Parts Technical BBS
"I can assure you that a bad exhaust valve guide will allow oil to 'leak' out of an exhaust. It never 'sees' the combustion chamber, leaks down into the exhaust system. On startup you will get a blue cloud AND droplets of oil coming out of the exhaust. Of course, as temperature rise in the system all this oil is most likely burned instead of expelled. Your situation seems to be more of carbon buildup though."
PLEASE tell me I dont have a problem..(Photo attached) - Pelican Parts Technical BBS
PLEASE tell me I dont have a problem..(Photo attached) - Pelican Parts Technical BBS
"I am not sure what car we are talking about here, but keep this in mind - with a bad exhaust valve guide the combustion chamber does not 'see' the oil. The oil can go straight into the exhaust and accumulate there. Once the engine is hot it will smoke but not necessarily from a spark plug burning the oil.
Been down this road several times before."
More information on smoking...Carrera that is - Pelican Parts Technical BBS
Been down this road several times before."
More information on smoking...Carrera that is - Pelican Parts Technical BBS
"Remember, if the exhaust guides are worn, oil can enter the exhaust system without ever entering the combustion chamber. Result, dry plugs and smoke at startup. Have rebuilt several 3.2's with just these symptoms."
Carrera valve guide advice - Pelican Parts Technical BBS
Carrera valve guide advice - Pelican Parts Technical BBS
"Bruce - remember that if your exhaust guides are bad the oil can travel from the rocker area to the heat exchanger without entering the combustion chamber. I.E. the plugs will not 'see' the oil. You can/will get smoke at startup because there is oil in the exhaust but not necessarily in the combustion chamber. This means you can have DRY plugs and bad exhaust guides. Be careful.."
2nd look at '88 Carrera (long) - Pelican Parts Technical BBS
2nd look at '88 Carrera (long) - Pelican Parts Technical BBS
"16k and the guides are worn? Are you sure about the mileage? My research showed that the original seals did 'too good of a job' in that the guide/valve stem area was not sufficiently lubricated. The new seals solve that problem, and I believe they are white in color. You may want to verify this with John Walker."
Premature valve guide wear - Pelican Parts Technical BBS
Premature valve guide wear - Pelican Parts Technical BBS
"Zen,
My take on valve guide wear has always laid the blame on the valve stem seals, not the guides themselves. The seals did not allow enough oil to the stem, and wear resulted. I suppose you could replace the original guides with anything (I would only use the original Porsche part) but without the proper seals (the white ones) you could get early guide wear again. I just replaced all guides and valves in my '88 at 110,000 miles with the original guides and white seals and I do not feel I have anything to worry about for years."
K-line valve guides - Pelican Parts Technical BBS
My take on valve guide wear has always laid the blame on the valve stem seals, not the guides themselves. The seals did not allow enough oil to the stem, and wear resulted. I suppose you could replace the original guides with anything (I would only use the original Porsche part) but without the proper seals (the white ones) you could get early guide wear again. I just replaced all guides and valves in my '88 at 110,000 miles with the original guides and white seals and I do not feel I have anything to worry about for years."
K-line valve guides - Pelican Parts Technical BBS
"It would also depend if the correct guide seals were used. The seals were, after all, what caused the problem. The original seals did not allow enough oil in to lubricate between the guide and stem and the premature wear was the result.
Do you have any indication that there is a problem now? How much, if any, smoke do you get on start-up? What is overall oil consumption?"
valve guides/valve job 1987 carrera - Pelican Parts Technical BBS
Do you have any indication that there is a problem now? How much, if any, smoke do you get on start-up? What is overall oil consumption?"
valve guides/valve job 1987 carrera - Pelican Parts Technical BBS
05-08-2011, 07:52 PM
#30
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"SUBARU Owners of some 2010-11 models may complain of high oil consumption or see smoke coming from the exhaust. In T.S.B. 02-115-11 issued on Jan. 20, Subaru said the problem in 2010 Foresters and 2011 Legacy, Outback and Impreza models probably stems from faulty machining of the holes for the intake-valve guides. The cure requires replacement of the cylinder head".
http://www.nytimes.com/2011/04/03/au...ef=automobiles
http://www.nytimes.com/2011/04/03/au...ef=automobiles
There is NOT high oil consumption and there is NOT higher carbon deposits on some spark plugs than others, hence I believe that the problem on the gen2 Caymans/Boxters is related to exhaust (and not intake) valve guides. This Subaru's TSB also refers to a N/A (Naturally Aspirated) BOXER engine and it talks about 'white smoke', the very same kind of smoke you can see on the Cayman vids posted on this link: The secret behind the exhaust smoke upon startup on the GEN2 base Caymans
Some testimonials from a Subaru's forum:
"No, because the machining error is the hole in the head where the valve guide seats. The compression test only checks between the valve seats, head gaskets and piston rings. (opposite side of the valves) The problem with the machining error is that some oil will trickle around the valve guide and get sucked into the cylinder when the engine is running."
NASIOC - View Single Post - High Oil Consumption Subaru TSB 02-115-11
NASIOC - View Single Post - High Oil Consumption Subaru TSB 02-115-11
"but seriously, i was at the dealership about a week ago to get a part. i was checking out the new legacy's and some salesman was taking an old lady out for a spin in an '11 legacy that i was just looking at. when she started it, i saw a puff of blue smoke and smell of oil out the tailpipe. i just gave a face and continued browsing."
NASIOC - View Single Post - High Oil Consumption Subaru TSB 02-115-11
NASIOC - View Single Post - High Oil Consumption Subaru TSB 02-115-11
PS: Does any of these symptoms seem familiar to you?!
