Something Awfully Wrong

Was out of town for 3 weeks, hop in my 99 996, made it about 1/2 mile down the road when I noticed some smoke behind me, followed by what sounded like someone running a lawnmower or weed wacker right next to the car. I got off on a side street and shut it down. Massive oil streak all over the road. Getting it towed. Based on the amount of oil all over the roads, I would be surprised if there is any left in the car. Is this the dreaded IMS failure ?

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I don't think the car would be running if the IMS bearing failed. Maybe more likely AOS??

Dang dude sorry to hear this. The lawnmower sound is what's scariest. Hope it's something relatively minor.

The AOS will not dump that much oil - when the AOS goes, oil gets pumped into the intake; the car would stall/hydrolock before it would dump oil as described. OP, it doesn't sound great, but maybe - just maybe - it'll turn out to be a rock lodged under the sump plate or some other bad-but-not-fatal issue. I can imagine your weed wacker sounding like the "marbles in a coffee can" that some people have described the sound when the car jumps timing and parts start hitting other parts. A hole in the engine block is one of the sure-fire ways of removing the oil from the car. On the plus side, you did the right thing by shutting it down and getting a tow. Hang in there; if you drink, take a shot or two and think about something else until you hear back from the mechanic.

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When the bearing seizes or undergoes RUD (rapid unplanned disassembly), the IMS can no longer do its job of ensuring that the valves are operating in time with the pistons; the timing gets sh**ty and parts that are not meant to touch come into contact. Even though the engine loses power (since the valves are no longer working as expected), inertia keeps the car rolling; unless the driver steps on the clutch (or slaps the tip into neutral), the pistons keep banging into whatever's in their way. But, of course, this implies that what OP had is IMS failure - he doesn't know that. I'm still hoping for the rock scenario.

I think Mr Cuda needs to chime in here. I don't remember him saying anything about a noise, but the rest sounds like when his chain got a little too slap happy.

Got it towed, will know more Monday morning, will keep you posted.

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+996. Sounds like the same thing. https://rennlist.com/forums/996-foru...today-and.html

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If you recall from my blown motor thread, the only noise was one brief "bang." Sounded like a rock hitting the bottom of the car, and the car instantly shut down. No weedwacker or can of marbles noises. But, mine wasn't the IMSB. It was a piece of the chain tensioner paddle that broke and was sent through the crankcase by the chain. Link: https://rennlist.com/forums/996-foru...today-and.html Hey, I think it still ranks in the top 10 for most views/posts! I may self-publish it on Amazon, or sell the rights to the story to Johhny Threadlocker. Would have been interesting to see pix of the carnage after JR took it apart, but I guess he got too busy to post them.

oh I don't like that. A 99 job same as mine. Out of interest, how many miles you got on the clock and do you track the car??

I've got 82,000 miles on it, no tracking, just my daily driver.

Did you notice where the oil was coming from? Had the engine had time to warm up before you drove off? Did you drive it hard just before the issue occurred?

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I live in a neighborhood with a 30 mph speed limit, so I always start out nice and easy. Never got the RPMs past 3000 before this happened.

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The oil was all coming out on the right side under the car, but I couldn't tell where from. Based on the amount of oil on the road(since I didn't notice it right away) I would be surprised if there is any left in the car.

Hopefully it's something like a; cracked oil pan, cracked filler tube, or cracked filter housing. Good luck.

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We're slipping here guys. This is the 996 forum and we have a good 36 hours or more to fill him with all the worst fears. Let's get cracking people! Then either he is prepared if it is indeed terrible news, or he'll be thankful when it's only a $500 repair

Really hope it is something simple, like maybe the oil filter got hit or blew apart. Did you look to see if the oil filter was intact?

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It was almost certainly caused by anthrax. Prolly only a few more days to live.

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I'm hoping it's something simple like this. Will know tomorrow.

Update... it sounds like a bad exhaust cam caused excessive pressure and something blew out causing the oil to leave in a hurry. Not sure what exactly this means yet and what the repair will cost, but since I shut it down right away and didn't run the engine dry, they don't think there should be any damage.

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Were the cam covers ever been removed and resealed? Sounds like too much sealant on the cam cover ends that caused the cam plugs to blow out.

^ That's what I was thinking, but it doesn't explain the noise.

Probably just engine noise from the cam hole.

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Oh yea, I missed that.

So the good news is that no damage seems to have been done. Cam cover needs to be remachined and the whole thing will take about a week before I get the car back. Looking at about $1700 for the repair which includes the tow.

Glad it's not something serious. However, this doesn't sound right as the covers and the heads are paired and machined together "Cam cover needs to be remachined"? The cam covers also form the cam bearings.

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+1...What was the issue that caused damage to the cam covers? It's definitely not typical to blow one off But I'm still trying to wrap my head around "a bad exhaust cam caused excessive pressure and something blew out causing the oil to leave in a hurry."

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Woohoo!! I called it. Get him all paranoid over the cost of a failed engine and then a normal repair bill won't look so bad! The 996 forum saves the day again Glad it's a minor thing and you'll be back on the road soon.

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Good questions and I'll get a better explanation when I pick it up so I can post it. Unfortunately I'm not a mechanic so when they explained it to me over the phone I probably missed something and am not explaining it right.

So what causes the crankcase to get over pressurized enough to blow the green plugs? AOS?? This was happening to someone a few years ago, can't remember what it was?

some ideas: http://forums.pelicanparts.com/boxst...owing-out.html http://www.renntech.org/forums/topic...nyellow-fluid/

good luck getting her back on the road

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I read the pelican parts post and this seems very similar to my issue, especially since I found a green plug under the car after I pulled over. I'll go back and check previous work done to see if there was anything involving the cams, but how would you prove it was improperly done and too much sealant used causing a blockage ?

Strings/blobs of sealant floating around the cams? Visible sealant along the outside edges of the covers? Even if you see this how would you get someone to warranty it?

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The plug blow-out is a symptom of over-sealing the covers; the oil passages get clogged and the plug blows.

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Ok, but how can you prove this ? If I go to my Indy and tell them, hey this plug blowout is a symptom of oversealing the covers, and you guys did some work on the covers, so it must have been a result of that, I doubt that would go very far.

But it is a good reason to not let them slap a new over sealed cover on.

Hopefully the mechanic knows something we don't and OP will learn what "machining the cam cover" means and what was done to correct the "bad exhaust cam." Let's give OP's mechanic the benefit of the doubt and assume that more details will be provided when/if OP requests them. OP, you mentioned you were going to check the service records to see if the covers had been resealed. Had they? If so, maybe that's all there is to the issue, but that doesn't seem consistent with their other comments. I know you probably don't know yet, but I encourage you to get them to explain it fully so you can be sure that they addressed the cause and haven't just resealed the cover and replaced the plug assuming it was a fluke...

So I pulled up the last service that was done on it and have attached the picture. Sounds like the sealant issue could have come into play ?

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Below is your earlier post, copied-n-pasted........could not have said it any better. P.S. If you decide to go thru with it, best to start looking for another indy

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This. As far as I know there is no exchanging or new cam covers. They are numbered list mated to the head and the bearings for the cams ARE the cover and the head. So at a minimum you would need to fly cut the head, mill the cover, line bore the assembly and then regime the cam.

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Regrind the head. Stupid autocorrect.

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fixed that find someone who knows these engines. the factory manual is very specific about how much sealant to use and where and I thought it was all BS. now I see why.

Regrind the Cam. Or replace the head and cam cover with a known good one. But I doubt any of that is necessary if its resealed properly.

Repairing this one is simple... If you know these engines. That said, this is a rookie mistake... This is what shops were screwing up 15 years ago. No excuse for someone to do this today. This screams M96 inexperience. Period.

I think you just show him this post and tell them you suspect the problem was a result of their repair. Seems well enough documented that this is a problem if not done the right way. I don't know, it cant hurt to try, maybe they will cut the bill at a minimum.

I'll provide update later this week when I get it back and get a better breakdown of what was repaired. I talked to them today about the issue of using too much sealant being a possible cause and they were very aware of that issue.

Got it back today, running great again. Here is the work that was done... had to machine the cam not the cover. Hopefully this explains it better

Interesting. Seems like a very uncommon issue? Also wondering what machine work was needed to reinstall a plug, but then I don't know how the original plug is designed. Screw in or press in or ??

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I repair these all the time.. Chuck it into the lathe and ream to a standard size. Drill and tap for a 1/4 or 3/8NPT galley plug (depending on which cam had the issue) and install the plug deep enough that the cam timing tools can still be used. Its a a classic failure driven by too much sealant used on cam covers... The sealant blocks the drain at the aft end of the cam, then runs the pressures through the roof inside the (hollow) camshafts... ThIs is what ejects the cam plug. Very rookie mistake.

So what's the recourse ? I can't exactly go and show them a post from a website and say, hey this was a rookie mistake.

Sorry for this misfortune but glad it was fairly easy to get fix and you are back up and running.

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Why can't you? If it was me, that is exactly what I would do. But, I do like challenging people on their bull**** work. Sort of a hobby of mine... If you aren't in a confrontational mood and they aren't willing to cover their mistake, then you need to say goodbye to your indy. I am also assuming that your current indy is the one that did the previous work.

Yes this Indy did the previous work, and they've been really good to work with for a long time. As I mentioned earlier, they were aware of the issue of using too much sealant when I asked them about it. I have no problem confronting someone if I know I'm in the right, I guess I'm just not convinced that this was the root cause, and there is no way to prove it.

Astro: Review post #50 above from Jake of Flat6. To many, including me, he is the M96(and other engines) engine wizard. If I was a betting man, I would bet on his advice as being accurate in this case. Without reviewing this whole thread, have you asked your mech. for an opinion as to why this occurred?

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Trust Jake for sure. If you want even more confidence, you will need to understand the anatomy of the head, the cam cover, and how the oil is pressurized. Without seeing it yourself and understand those, you will never be convinced if you are that skeptical.

You said it's the same indy sealng the cam cover and they are well aware of the "too much sealant" issue. Do they also know too much sealant will cause the cam plugs to blow out? If they do, they should take some responsibility of the previous work. If they don't, what was their explanation of cam lug blown out? When they said they were aware of the too much sealant issue, maybe they only meant they knew excessive sealant will clog the oil pickup screen in the oil sump.

If you do have a good relationship with them to the point that they recognize you and know your name when you walk in then ask them if they know who Jake and FlatSix is/are. If so (likely, since I assume they install his inventions) then I'd mention that the prevailing opinion is that the problem is likely due to the sealant. You can do it without getting all confrontational, if they flat out deny, well, then it's up to you as to how you want to move forward. If they generally do good work and there aren't others in the area you probably should just suck it up. But if they value you as well they may be willing to discuss it more. But yeah, don't go running in there waving printouts of this forum discussion around and start screaming about how justice must prevail and you insist on restitution blah blah blah. That won't get you far :-)

Maybe I just keep missing it - but what's the source of the damage/scoring to the cam that had to be polished out? AFAIK, blowing the cam plug due to the sloppy sealing issue shouldn't have resulted in scoring to the cam. Is the scoring due to insufficient lubrication once the plug was blown?

They weren't able to identify the root cause, just the fix. I spent some time discussing what to do to prevent this from occurring again, and they didn't feel it could be identified.

So what was the final decision, are you letting it go or are you going to make a further case to get some compensation? Been following your story, just curious, no pressure here.

Unfortunately I think I'm going to simply let it go. It was painful to spend another $1900 on repairs, but I'm simply not enough of an expert on this topic to go and get compensation. The car is running great and is headed for winter storage in my garage shortly.

Glad your car is running well again. Good plan to forget and just enjoy.

The real drag is that you spent $1,900 with absolutely no confidence that the underlying issue is resolved. OP, you have a whole lot more patience than I do.

The cam plug is just pressed in like a freeze out plug. When one "pops" out it cannot be reused. The best repare is to drill and tap the cam, machine it, and screw and glue a plug in to it. (Set screw and thread locker) as Jake said. Note that the original work was done on bank 1. The plug was ejected from bank 2. That would give Indy plausible deniability unless they had to remove both cam covers to lock down the cams? If one were rough enough with the cam locking tool the plug in the end could be disturbed enough to work out later. Especially if it is a "home made" tool. A problem that one Rennlister had a few years back.