AOS, Intermix, both?-FIXED
02-17-2011, 12:19 PM
#31
Rennlist
Lifetime Member
Lifetime Member
02-17-2011, 12:36 PM
#33
I don't mean to be too argumentative, and I have a lot of respect for Macster and his experience with Porsches. But with all the AOS failures that have happened, and AOS failures are pretty common, I have never heard of a hydro lock caused by an AOS failure, here, on any of the other forums, mentioned by Jake Raby, or any one else for that matter.
I would think that if this type of failure was occurring we would have heard of it, we certainly here of just about every type of failure that does occur on a regular basis. For 3+ tablespoons of oil to be drawn out of the AOS, through the plenum, through the intakes and into one cylinder, and not burnt off during the combustion and exhaust strokes implies a huge amount of oil. IMHO
And if you disconnect the line from the AOS to the plenum you have cut off the source of the coil. Then again, a couple of hundred dollars for a tow is not that bad to prevent potential damage to a car.
I would think that if this type of failure was occurring we would have heard of it, we certainly here of just about every type of failure that does occur on a regular basis. For 3+ tablespoons of oil to be drawn out of the AOS, through the plenum, through the intakes and into one cylinder, and not burnt off during the combustion and exhaust strokes implies a huge amount of oil. IMHO
And if you disconnect the line from the AOS to the plenum you have cut off the source of the coil. Then again, a couple of hundred dollars for a tow is not that bad to prevent potential damage to a car.
Yes, you should do whatever makes you feel comfortable.
02-17-2011, 12:53 PM
#34
Race Director
I don't mean to be too argumentative, and I have a lot of respect for Macster and his experience with Porsches. But with all the AOS failures that have happened, and AOS failures are pretty common, I have never heard of a hydro lock caused by an AOS failure, here, on any of the other forums, mentioned by Jake Raby, or any one else for that matter.
I would think that if this type of failure was occurring we would have heard of it, we certainly here of just about every type of failure that does occur on a regular basis. For 3+ tablespoons of oil to be drawn out of the AOS, through the plenum, through the intakes and into one cylinder, and not burnt off during the combustion and exhaust strokes implies a huge amount of oil. IMHO
And if you disconnect the line from the AOS to the plenum you have cut off the source of the coil. Then again, a couple of hundred dollars for a tow is not that bad to prevent potential damage to a car.
I would think that if this type of failure was occurring we would have heard of it, we certainly here of just about every type of failure that does occur on a regular basis. For 3+ tablespoons of oil to be drawn out of the AOS, through the plenum, through the intakes and into one cylinder, and not burnt off during the combustion and exhaust strokes implies a huge amount of oil. IMHO
And if you disconnect the line from the AOS to the plenum you have cut off the source of the coil. Then again, a couple of hundred dollars for a tow is not that bad to prevent potential damage to a car.
My Boxster has been through 2 of these AOSs and the engine has not suffered any harm. But as I mentioned, I avoided running the engine for too long.
Also, the 1st time my Boxster engine's AOS was acting up the engine consumed quite a bit of oil: The oil level went from the max line to just above the min line from burning oil that was being pulled through the AOS.
The problem with the oil is it is not compressible and the piston has to reach the top of its stroke before the combustion cycle can begin. So the oil can't burn off before it can do its damage.
The other possibility is the intake walls get very wet with oil and this oil as the engine sits drains down into one cylinder. (This is the primary mechanism from which these engines exhibit the smoking upon startup behavior.) Upon the next engine start the engine controller may not be even be triggering fuel and spark on at the cylinder (or cylinders) that has the unfortunate luck to be the gathering place of this oil.
Sincerely,
Macster.
02-17-2011, 02:28 PM
#35
Nordschleife Master
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The Grand Am 3.4 and 3.6 GS cars had hydro lock problems which is why Motorsports created the 2-chamber AOS. I too doubt that under street conditions you could cause a hydro-lock, but they seemed to blow them up regularly in GA until Porsche created the 2-chamber version. That fixed it...
02-17-2011, 03:10 PM
#36
Drifting
If you are worried about hydrolock
plug the aos as described.
pull the plugs.
you can boroscope or other wise inspect the cylinders.
pull the fuel pump relay.
turn the car over,
see if any oil comes out the spark plug tubes.
maybe even put some paper towels in the tubes to absorb any oil
that comes out so that there isn't a huge mess.
If you get a ton of oil out of one of the tubes -- you saved yourself from hydrolock
either way -- put it all back together (except aos plug) and if
you want fix the aos yourself or - drive it to your mechanic.
mike
plug the aos as described.
pull the plugs.
you can boroscope or other wise inspect the cylinders.
pull the fuel pump relay.
turn the car over,
see if any oil comes out the spark plug tubes.
maybe even put some paper towels in the tubes to absorb any oil
that comes out so that there isn't a huge mess.
If you get a ton of oil out of one of the tubes -- you saved yourself from hydrolock
either way -- put it all back together (except aos plug) and if
you want fix the aos yourself or - drive it to your mechanic.
mike
02-17-2011, 03:13 PM
#37
Drifting
BTW,
if you do have intermix -- I get concerned about the antifreeze pitting the bearings.
I tore down my Boxster S and replaced all wear items when I had my intermix --- maybe
over kill -- but 25k miles later -- no problems.
mike
if you do have intermix -- I get concerned about the antifreeze pitting the bearings.
I tore down my Boxster S and replaced all wear items when I had my intermix --- maybe
over kill -- but 25k miles later -- no problems.
mike
03-07-2011, 04:46 PM
#38
Rennlist Member
Thread Starter
I just wanted to provide an update and some thanks on this project.
I replaced the AOS by removing the intake manifold and pulling it from the top. It was an annoying job, but it was doable and it resolved the problem. In order to gain more access I removed the coolant reservoir. I suspected this would give me some more working room so I had already ordered an updated tank and cap. After starting on the first few bolds on the intake manifold I realized how much easier things are without the tank in the way. I have a C4 so the fuel filter is mounted between the manifold and the coolant tank. That was providing additional constraints. So in the end I pulled: air intake, throttle body, cross tubes, coolant tank, and fuel filter. That gave me room to remove the driver side manifold and reach the AOS.
I couldn't believe how much oil had been sucked into the manifolds. I'd estimate at least 1/4-1/2 cup of oil drained out of the two sides. After getting everything together it smoked liked crazy but it quickly cleared up. I cleared the codes and drove it home. I just dumped a bottle of Techron in the gas tank to try to clean up the carbon and residual oil on the plugs, valves, and combustion chambers from the oil.
Thanks for all of the advice and the troubleshooting.
Shawn
I replaced the AOS by removing the intake manifold and pulling it from the top. It was an annoying job, but it was doable and it resolved the problem. In order to gain more access I removed the coolant reservoir. I suspected this would give me some more working room so I had already ordered an updated tank and cap. After starting on the first few bolds on the intake manifold I realized how much easier things are without the tank in the way. I have a C4 so the fuel filter is mounted between the manifold and the coolant tank. That was providing additional constraints. So in the end I pulled: air intake, throttle body, cross tubes, coolant tank, and fuel filter. That gave me room to remove the driver side manifold and reach the AOS.
I couldn't believe how much oil had been sucked into the manifolds. I'd estimate at least 1/4-1/2 cup of oil drained out of the two sides. After getting everything together it smoked liked crazy but it quickly cleared up. I cleared the codes and drove it home. I just dumped a bottle of Techron in the gas tank to try to clean up the carbon and residual oil on the plugs, valves, and combustion chambers from the oil.
Thanks for all of the advice and the troubleshooting.
Shawn
03-15-2011, 02:03 PM
#44
Rennlist Member
Thread Starter
Not only do they help applying force in tight spaces to compress the clamp, but the locking mechanism is a huge help. You can compress the ring and lock it open while you get the hose on the nipple. Release the lock and the clamp tightens up. Like magic...
