AOS/Cropduster

Well,, bad weather had the car in the garage on the battery tender for about a month.. Started and backed up ,, saw a very very light puff of smoke.. But it does that when its been sitting. Headed down the road,, driving at 2800rpm,, stopped at the on ramp and as I tooled up to get on the highway,, poof,, right side starts puffing like a steam engine,, and the CEL comes on.. pulled over and massive vacuum on the oil cap. got turned around and idled it home (Luckily less than a mile.) Called the local indy,, he has a spot this week to do it and can take it any time. So she gets a new AOS , AOS hoses and the normal fiddly things while they are in there ,, he said the $ will be right at 1100 unless something truly extra wrong is found.. Unfortunately I'll have to have it taken on the flatbed,, he didn't recommend driving it if it has continuous smoke and mis-fire, said he's seen too many cats ruined that way,, luckily my roadside assistance insurance will cover that.. My 2006 330Xi cost about 1400 for the same problem ,,,, what can ya do.. ??

Not only is damaging the cats a concern, but engine hydrolock is also a concern when the AOS has failed that badly..Advise them to turn the engine by hand a full ,720 degrees before attempting to start. Oil collected in intake can drip down and fill a cylinder after sitting/ riding on tow truck..

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interesting. If oil has filled the cylinder and you manually rotate through 720� where does the oil go?

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If you have ring and valve seal, nowhere.

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If the plug is pulled it will spill out of the plug hole. With the plug in, the crank will stop turning as the oil in the cylinder will hydro lock. Ask me how I know...My (Not) Blown motor thread will educate you on the process.

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Oil will not compress. Like Jake and Bill said, the crank will stop before 720 degrees IF there is hydrolock. This is a test to safely determine if enough oil has entered the engine to cause hydrolock. When using the starter to try and crank a hydrolocked engine , enough torque can be generated to bend a rod or other damage.

PDX, sitting where you are, I'd consider deferring the repair until PT3's solution comes on line & maybe while everything's apart add that in. Just thinking out loud here.

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This is the second one in a week that has failed that bad, az968gpw had his tested and was 25" h20!. He has downed it until spring waiting on the Ultimate AOS to be finished and also doing some other things while waiting.I am working on it..

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Yes, that makes more sense. It won't go 720 degrees!

The local guy worked on my 69-T 20+ years ago,, hes been around.. Yea we pushed it out of the driveway and then it went on a flatbed to the shop specifically to avoid any attempts to start till the plugs are out. They will check it out.. should be back to me on it by Thursday. Luckily for me,, they had a bunch of cancellations for service work do to weather so he has a bay and 2 techs free Cant really keep the car offline at this point, I'm in mid process of moving. But the new place will allow me to go back to doing my own work. Fingers crossed nothing else went with the AOS,, my motors oil tests were perfect, and the cams were almost dead on. Not sure which way I'd go if its got issues.. WOuld probably depend on any carnage level.. I don't think it got more than a mile or so total time till I got it back home. luckily I only had to go from my exit to the next and back and they are close together..

Have you considered a temporary bypass of the AOS until you can do the serious work?

Well,, looks like it resolved itself,, its hurt ,, something cracked,, Will be talking to the shop tomorrow once they finish scoping the motor. Had Coolant in #1..

ouch. sorry to hear that.

Yep going to be a decision week or two,, depending on the verdict,, first thing is getting the car on a trailer and hauling it to my storage.. Not going to panic, just take my time.. we bought it as a luxury ,, just may end up a little bit deeper than planned.

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That sucks. Sounds like a story I know all too well. Best of luck. We're all pulling for you. Keep your stick on the ice.

Leak is at the head/cylinder junction, they were not able to get the camera close enough to tell if there is a crack. No visible cracks in cylinder that they could see. No bore issues from below on that side,, He's trying to not add to the bill more than necessary.. So now,, its sort time, Time/Money/Reputation hmmm, decisions..

Sounds like u have to pull the head. Not many other options now.

Yep ,, and honestly even if it was a head gasket only,, there I'd be,,, paying probably 3500 to tear open a 116K Mile engine.. I mean,, once the head is off,, you almost have to take it down to a shortblock, replace both gaskets, timing chain guides... Where do ya stop?

So it goes. Never know until you know but there are predictable conditions that lead to mission creep. Hope that it is one of the more fortunate repairs. Where did you take it? Matrix?

Marque Motors,, I used them for years on my 69T ,,, I'm guessing with the speed the water goes in its a head gasket. I think if it was a cracked cylinder it would be visible with the bore scope, I'm tempted to stuff the car in storage for a couple months, I'm in mid house selling buying right now,, new place will have enough room for me to work on it.. I'd just farm out the machine work and dive in then..

Nope. The cracks most often occur under the lifter carrier. No access with any bore scope to this area.

^^^ I didn't make that line long enough,, I meant like a full on deep cylinder wall crack ,, I am assuming that these start at the top edge,,, and head south. And at this point there is no visible coolant in the oil they drained. That was the main reason I was thinking head/head gasket. I've seen engines hydro lock,, so if the AOS failure filled the cylinder with oil, I may also have a rod/piston issue on top of the head problem. Nothing is sure I guess till its apart.. Then we start the fun..

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These engines do not have head gasket issues. The MLS gasket is considerably more robust than the block, or the cylinder head. BOTH will fail before a head gasket fails. It simply never happens.

Jake,, Hmm,, if you hydro one,, can it lift the head? I've seen that on LS motors.. And some others.. I guess i'm wondering what a hyrdolock "typically" does to a 996 engine.. If that word can even be used .. Basically I'm assuming,, and thats risky ,, that with a full cylinder of coolant with a small tick of oil the failure is most likely top-end.

Forget that other experience. If you hydro one of these, the head gasket is the last thing that will fail. This one hydroed, we pulled it apart in M9X Engine Rebuild School earlier this week. Head gasket was unscathed. You treat this engine, like this engine- nothing else~

Jake, thanks for the responses! yep that's exactly what I'd expect,, I should mentioned most of the engines I've seen do it,,, did it under a lot of power and it was 100% carnage, the head bolts stretched during the event. So one cylinder was like the pic, but the neighbor had water in it too.. So at least my expectations are in line.. We have not opened the engine up yet so as not to make the process harder if I send the whole car somewhere. Oilpan and bore scope only. Left intake is off so as to get all the oil out of it. They had it off to do the AOS that's when the coolant issue came up..