Very broken 2002 3.6 996 C4S

Its a shame my first post has to be one like this but sadly my beloved 4S died in tremendous style on saturday night and I have my suspicions of what it may be but looking for any advise as nothing I've researched quite matches what happened. 77k miles on the clock and in great condition, no problems at all - engine quiet as anything - Ive had it for almost 4 years. Going along on saturday about 60mph and dropped a gear to overtake on a dual carriage way and felt the car hold back but then it cleared and was fine but a few seconds later, rattle noise followed almost instantly by a huge cloud of smoke out the back and the engine cut out and I coasted to a stop at the side of the road. Obviously I've not tried restarting it as this felt horrible - I didnt hear a bang or anything. Instant fears running through my head were the IMS or the RMS (including the bearing) letting go or even a cracked liner which I know is far less likely on the 3.6 but this kind of seems most likely. I havent had a chance to get under the car yet but will tow it to my little workshop in the next few days after work - I build engines and play with cars as a hobby so am very competent when it comes to working on cars. It felt bad, like something nasty breaking if that makes sense and im incredibly concerned as I cant afford a new engine. The odd thing however is that there is no sign of oil anywhere so whatevers happened there doesnt appear to have been any oil escape - nothing dripping underneath. The cloud of smoke pouring out of the rear spoiler vents also cleared very quickly and didnt smell of oil at all and also when i put the ignition back on, it said check coolant. This obviously leads me to think the cloud of 'smoke' could have been coolant however there is no coolant leaking underneath either - literally nothing dripping out but the coolant reservoir is empty. This would indicate the coolant hasnt dropped out but has gone into one (or more) cylinders and been burned which which indicate a liner letting go. Any thoughts at all would be very much appreciated and hopefully I'll get to look underneath at the weekend. Thanks for taking the time to read such a long story.

Sorry to hear about your "event".. I have heard of similar catastrophic events occurring when downshifting/missing a shift. It is typically a broken timing chain. But your smoke and coolant beg to differ there, unless you ended up internally smashing some valves/piston material through the cyl walls etc.. I had a catastrophic event around February this year, and have just been repairing it myself as I have time, these aren't that complicated to work on, I like you did not have the money to replace the engine but also wasn't willing to give up on the dream.

Really crappy man. Unfortunately, it doesnt sound good at all. Keep us posted on the outcome please.

I will certainly do as much as I can myself but I've always worked on front engined cars that come out through the top and not ones like this that drop through the bottom and as such I dont have a vehicle lift but for this job I think I'm going to need to invest in one. Will still be cheaper than paying someone to remove the engine for me. Timing chain is the thing thats been bouncing about in my mind - I feel physically sick at the moment. I'll do some basic checks but then I will drop the gearbox as this will give me a lot of visibility as to what the problem could be.

A lift will make things a million times easier but it is not necessary. Few here have rebuilt the entire drivetrain of their porsche in the garage with jack stands and common jacks. engine comes out the bottom, easier to pull it all (trans and engine together)

Count me in that field. I'm not doing a full rebuild, just a head rebuild and a ton of preventive maintenance. But still, did all the work this far on my own with a floor jack, Aasco Jack stands (and harbor freight stands as backups), and two transmission jacks. Engine out, mounted on stand. Curious to see what your problem is.

You don't need a lift at all and you will learn to appreciate the "wrong" engine placement to work on these cars. All you need is a regular 2.5Ton floor jack : PM me if you need more info

I pulled mine out with a motorcycle Jack and a 2 ton car jack and 4 jack stands.

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Sorry to read of your apparent engine failure. I hope it is something much less than that though. You were smart in *not* trying to restart the engine. When an engine quits on its own with smoke, noise, it is never a good idea to attempt a restart. Have no idea what happened. Doesn't read like a failed IMSB and the empty coolant tank is AFAIK not a common -- even an uncommon -- symptom/side effect of a failed IMSB. If I had to make a guess I'd say the AOS failed and in quite dramatic fashion and the engine had a load of coolant routed to it via the intake. If I'm right then the engine might not have suffered any real damage but of course the plugs removed and the oil must be drained and replaced and the bad AOS replaced and the cooling system properly refilled -- no air pockets! -- with fresh coolant. As soon as you can with fresh oil in the engine and the AOS replaced -- assuming of course this is the problem -- the cooling system doen't need to be refilled turn the engine over by hand. If it locks you're done. If you can turn it by hand continue to turn it two or more revolutions then use the starter to spin the engine and flush as much coolant out of the cylinders as possible. I have my fingers crossed you can resurrect the engine without any need to remove the engine and disassemble it.

That's an interesting thought - that never actually crossed my mind. I would love you to be right although somehow it 'feels' worse than this - how would I go about checking that out before I start ripping the engine apart? There was a rattle however before the smoke plumed out the back - this is the bit that concerns me most as whatever it was clearly just let go causing the smoke and engine cut out.

Drain the oil through a filtered funnel... Then pull the sump plate and post what you find without cleaning anything first. The sump is the window into the soul of the M96 engine and any failure.

An AOS is a possibility; a cracked head is also a possibility. Regardless of how it winds up there, when you put coolant in the cylinder, two things happen: One, you lose combustion in that cylinder - so your flat 6 becomes a flat5 or less; and two, you have the possibility of hydraulic lock, which in many cases is a misnomer since the engine may overcome the "lock" by bending or breaking the parts that cannot move due to the presence of an incompressible medium in the cylinder. On the plus side, both a blown AOS and a cracked head can be cheaper to fix than something deep within the engine grenading. If you do pull the plugs to check for coolant as Macster suggests, scope each cylinder to look for damage. If you do decide to turn it over by hand, do so very slowly and carefully so you'll be able to feel any interference...

Thanks guys - I'll attempt to tow the car to my workshop at the weekend and drop the oil as suggested by Flat6 followed by the filter for any fragments of metal. I'll also look for signs of oil/water mixing.

Drain the oil and pull the sump before anything else is done.. What you find there may curb any other efforts... If you find debris, it does;t matter whats wrong; its coming apart. M96.03 have the following primary failure modes: -Timing chain failure -Valve seat failure (loosens, and falls out of the head) -D chunk failure of a cylinder -IMS Bearing failure (of course, its a factory single row)

Thanks very much - thats exactly what I shall do. I had a brief look underneath last night where its parked at my flat just to see if there is anything obvious. Well the good news I guess is that theres no holes in the block so nothing made a break for freedom Coolant is low now but there is still plenty in the system (from squeezing a coolant hose to the block) and it definitely didn't over heat and never has. There is absolutely no sign of contamination of the coolant in the reservoir. There is plenty of oil showing on the dip stick (half way) - a little dirty but again no sign of contamination. Bit gunky in the oil filler tube where some oil has emulsified with moisture but from my experience this is very common around the filler due to general moisture getting in. I dont think this is related in any way. Moving underneath I was half expecting fresh oil around the RMS and IMS region however nothing there at all. Not a single drop of fresh oil and if there was a failure here I would expect to see oil so I'm moving away from thinking this is the issue. My thoughts are still a snapped chain but I guess I'll find out when the sump plate comes off. One interesting thing that may be very relevant - looking from the back, the left exhaust tail pipe is very black (dont recall it being like that before), the right one isn't. This could potentially indicate some kind of failure and oil burning on that bank of cylinders. Next job is to tow it to my workshop one evening this week and then drop the sump plate on the weekend. Thanks so much for your help so far.

Here's hoping it all goes well. The left tailpipe is bank 2, the right side of the engine cylinders 4-6, AND where the AOS breather hose attaches. So it's possible your AOS diaphragm blew and dumped a bunch of coolant in the engine and locked it up. It will be interesting to see what you find.

Hello, so here is a better picture of my engine drop rig. Basically it's home improvement store alternative to buying a motorcycle jack. Btw, if you have one or have access to one, use it,. I did not want to invest in one so this is a 15$ alternative. Works like charm and I did a few drops and reinstalls, alone, without any issues. --------------------My little write up---------------------------- I prefer to work with a car jacked up to a minimum height necessary while I disconnect everything and raise it higher when the engine is lowered. Simply rolling on ramps is enough to do most of the work. When I put the rear on stands I use more than just two stands in the back. I always put wheels underneath and even pile up some 2x8 on it. It's just me but I prefer two have more safety. 1. Once everything is disconnected in a proper way (there are guides for that ) , disconnect the transmission from the body and lower it on a spare jack stand using a jack. Let it hang in there. 2. Attach this rig to a proper 2.5 ton automotive jack, you need to remove the saddle and bolt it tight. Don't use it if you can not properly bolt it to the jack. Place it under the the sump plate, eye ball it to be as centered as possible. Remove two engine mount nuts and lower everything. 3. Here is where you still need a SECOND jack. You need to lower the transmission from that jack stand onto some sort of a trolley - I use a small snowmobile trolley, comes in package of 3 and cost 25$. If you don't have access to a second jack - my rig can be lowered onto two small jack stands, and then you can disconnect the rig from the jack and use it . 4. Assuming you have 2 jacks and you have the engine lowered to the maximum and tranny on a trolley, using your second jack, you need to raise the car up sufficiently to clear the engine from under. It will roll just fine and the trolley helps a lot. TIP - to raise the car sufficiently, you need a good solid jack and some sort of an extension. Amazon and eBay sells 4" extensions, I simply got one done at a local machining place. They turned it out of plain metal cylinder.

Thanks very much - very useful info. I have already ordered a floor transmission jack which will do a great job on the transmission itself and to be honest I may well remove that separately anyway this weekend. The car is on 77k miles and on the original clutch so it would be silly not to change this regardless. I also have one good 3 tonne jack along with stands and numerous Honda scissor jacks - I'm a honda nut - should have stuck with them instread A jack extension is an interesting idea and something I will definitely look into getting. Hopefully tonight I will get the car towed to my little workshop. Doing it myself will save a little more money towards sorting this engine.

One last thing - do your self a favor and drop the engine WITH transmission on it first. Keep us posted!

Out of interest - why do you say to do it that way? Is it simply a case of saving time and work?

it's a lot easier to take it out (and put back in) together.

Just as AWDGuy said, Because that thing is heaavvy, unless you'll be doing it on a hoist, with a proper transmission jack and another one to hold the engine in place. It's still a bit PITA to put it back on even when the thing is on the floor and the engine sits right next to it. In your case, your problem is the engine, so why would you pull the tranny off first anyway?

Reason being that I thought it may be easier to take them out in 2 parts as I wont be using a lift for the very reason that they weigh so much but from what you've all said, it probably doesnt make sense to do it this way. I have a proper 150kg transmission jack and I have a huge mobile engine hoist.

This is how it comes out No need for much else

So I successfully managed to tow the car 9 miles down the twisty country roads last night and its happily tucked up in my little workshop perfectly positioned ready for the next stage. Feeling happier about things already - at least its safe and out the way.

OK so its update time. Not particularly pleasant unfortunately but at least I've made progress. So I dropped the oil and about 5 litres of coolant came pouring out first so I think thats the give away that its cracked a liner. That would also explain the sudden burst of smoke - or steam as it appears to have been. Dropped the sump and there is a lot of metal in there. A threaded section which can only be the bottom of one of the rods, some chunky bits of cast metal which could well be liner and some very very thin metal which looks like some kind of shield thats been torn apart. Its way too thin to be anything significant. To me it looks like a liner has let go, effectively hydrolocked a cylinder and broken the rod but I wont know more now until I pull the engine apart. I'm still hopeful that new liners and some internals will see this engine back better than it was before. I've now started work on pulling the engine from the car. Pictures here so please let me know your thoughts.

Sorry about the size of the pictures - I'll resize the future ones.

new engine time. Hopefully this engine can still be salvageable.

My plan will be to have this engine re-worked as opposed to getting hold of a new engine. I will have the original (most likely broken) liners bored out with complete replacements fitted - will still work out cheaper than buying another engine. The other benefit being I know its been done properly as opposed to buying a second hand engine which I have no knowledge of and no guarantees. A new engine (as in brand new) is not an option.

4.0 from Autofarm...!?

Dont forget i'm in the UK for starters so our options are slightly more limited however my aim is to probably go for 3.8 using new liners and pistons. I've found the place I plan to use but need to find the time to get the engine out and at least partially stripped down.

So i looked up autofarm and realised they are here in the UK - wasnt expecting that - interesting.

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The guy in Florida does his engine rebuilding in Poland. You can prob get it shipped for less than $500 while you are still in EU. Lots of people travelling that route in cars. Might be another option. MB motorsports?

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Except that there are very lengthy threads for how crappy they treat their customers when there is an issue. I would strongly recommend against them.

Hartech here in the UK are probably my favourite option at the moment.

It would help if the debris was washed / rinsed with solvent so the pieces are more easily seen and the type of material they are possibly determined. If a rod had failed I think you'd see more rod metal, parts of the rod that make the identification more positive. Still, the amount of debris doesn't bode well. That ain't going to buff out that's for sure. One has to wonder if the engine is a viable candidate for a rebuild? However, I read you are considering AutoFarm? If so someone there I think can made the call on the engine. Rebuild (with probably new sleeves, etc.) or replace (and possibly rebuild before installation). Regardless, here's hoping for a good outcome whatever route you go.

You might look into the cost of a short block as well. They are currently running $6K in the US through Porsche (after core charge refund).

Worth the question although generally we get screwed by the OEM's here in the UK.

That threaded piece looks like the tip of a head bolt. If true, you may also need a new crank carrier. I hope your crank is salvageable.

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I think they are one of the best around there in UK and Europe. A lot of experience in rebuilding engines, and in Europe one of the pioneers in modifying the engines for cooling problems. They have also tons of information available. Check for example their buyers guide.

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Have a chat with Baz. Once he took a call from me, for a quick chat, on Dec 23 just before they closed shop for Christmas. And I was calling from New Zealand!

Another option - advertised as a new short block: http://www.ebay.de/itm/Porsche-Carer...AAAOSwTZ1XnGtj 8500 Euros (or best offer) No affiliation. GL w/ solution.

So both Hartech and Autofarm have given me a call today and talked to me in detail following me emailing them pictures. Both have agreed that I will remove the engine and pull the heads to find out exactly what is broken - I will then send them pics and see what they can do.

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I too used a motorcycle jack for the engine. Engine hoist made lifting the car for clearance easier.

I was in the same situation, I was forced to go with a replacement engine as my crank had been damaged and they are hard to get hold of, I ended up buying a used engine and stripping it to refresh it, Hartech honed my cylinders and fitted strengthening rings to prevent d chunking in future , I would say with that level of debris your going to have a fair bit of damage , I have some parts left over if you need anything, I know loads of places to get bits also in uk if you need anything message me ok You just need to get the heads off and possibly pull off the 456 side of the engine casing, if you have the engine in an engine stand swivel it so 123 side is facing down , undo all casing bolts and you can lift it off by hand , you will then see right inside, don't worry nothing will fall out it all sits in the other casing half, you will just expose the bearing carrier and rods and Pistons for 456 but you will see the damage that's been done I would imagine, you mentioned a thin metal piece before, that sounds like the timing chain baffle , if that's been chewed I'm wondering if you have had a timing chain failure??

Thanks thats very kind of you - I expect I will certainly be in touch with you. I've made a good start on getting the engine out but I only get a few spare hours here and there. I hope to have it all out by Sunday and then I'll start pulling it apart. Most of that material in the sump is the weird thin stuff - its a fraction of a mm thick and its painted/coated so its nothing load bearing hence me thinking its a shield or something. The baffle suggestion sounds about right.

Couple of quick questions. I'm using the Pelican guide to make sure I dont miss anything and it seems pretty good but I have 2 queries. Firstly the diagonal braces underneath - I've undone the bolts at either end and the one visible nut on one of the 2 middle mounts but how do I remove it? It seems very happy on those 2 central mounts - do they just pull out? I didnt want to lever it just in case im missing something. Secondly and im sure im being really dumb here but I cant seem to see the 17mm and 19mm fuel line connections that it mentions in the guide. I'm looking everywhere on the left hand side of the engine (standing looking from the back) and I just cant see them - am I missing something silly here? Many thanks

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Those braces just pull out. The only fuel connection you need to disconnect is a quick connect left of the left intake manfold. Top left of the engine bay. No tools needed unless the c4s is different than c2.

Ahhhh - I thought the quick release version was for the 997. That makes more sense as I cant see how I could have missed these. I'll have a look tonight as I should get another hour or so on it.

I believe Porsche has now designated the 996 as a "Classic" meaning that prices at your OPC's are at a lower rate than for more modern models. I am not completely sure if that only applies to labor rates or also parts. It might be worth a general inquiry, I remember reading about it in Total911 or one of the other British Porsche rags a year or so ago.

Almost ready to drop now. Gold star for Ahsai - fuel line was lovely and easy - different to the Pelican guide. Couple of gearbox bits to unbolt and the power steering hoses still and then I'm ready to lower on Sunday. Will send the ARB and diagonal braces in for blasting and powdercoating I think along with some new droplinks whilst im at it.

OK so a bit more progress - apologies but still no diagnosis of whats actually happened but I have now got the engine out of the car and thanks to all of the help on here it was pretty straight forward considering it wasnt done with a lift. Four stands, one trolley jack, one transmission jack and an engine hoist. This is me after finally getting it out. IMG_0142_zpsnp7qv3tu.jpg

woohoo! another step closer.

good luck finding replacement or rebuilding

Had a wedding at the weekend so only got an hour or so. I've pulled almost everything off the engine now and labelled it all up on some shelves so that it should be easy to put back together. Gearbox is also off and the clutch is pretty worn so definitely worth putting a new one on. Looking down into the intake side of both heads, no sign of anything untoward on the valves so it doesnt look like there has been piston to valve contact but further investigation needed obviously. Saturday I have most of the day so this will be when the heads finally get pulled off and we should have an answer.

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I thought the threads related to them not agreeing with some philosophy/expertise claims of certain boards members not on how they treat their customers. I have seen a number of members from here very satisfied with the engine and price they got back from them. sorry off topic.

Right - I got another hour last night and pulled off the flywheel and the IMS cover and something doesnt look right here. The bearing itself spins fine and there is no sign of any fresh oil leaks however the bearing is not sitting evenly in the hole - its completely off centre which presumably means the IMS must have broken in order to shift like that? Apologies the pics arent great but it wasnt easy to get a shot straight on. Let me know your thoughts.

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It's off center because you failed to do one, or more of the following: - lock the engine at TDC 1 - remove the IMS tensioner - remove bank 1 tensioner These 3 things are what should be done before even attempting to remove the IMS Bearing flange.

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This.

The shaft is being pulled to one side by one of the chains - no drama

Ahhh makes sense - also makes me look stupid Appreciate all the help that is being shared here. I was eager to have a look and honestly didnt even consider it at the time. Heads will be coming off next anyway so will be relieving tension off both main cam chains to do that. Hopefully will get everything stripped tomorrow as I have a good few hours spare so updates on Monday.

Be careful with the head bolts, use a good quality torx socket that fits correctly, they are really tight if you slip and round one off you will be in trouble, I used a long breaker bar , it gives control and power at the same time, it helps if someone can push down on the socket to hold it in firm while you turn the bar, turn slow and steady, it was the way I did mine, some may use impact but I think it's easier to mess up if it's your first time!!

Right so its not good but there are some small positives. I've removed both heads and as expected one of the cylinders has collapsed in spectacular fashion and the piston is nicely broken. Its number 1 that has gone and my guess is that a crack in the liner lead to a hydro lock but I guess its irrelevant how it happened. Now that in itself im ok with but the block has cracked as well so its scrap Now for the positives if there is such a thing. Both heads are fine, the intermediate shaft is fine, (chains were all ok) and it appears the crank is fine but I need to investigate further. I've got pictures but forgot my lead to upload them. Will try and do them tomorrow.

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Since Nickies cylinders don't use the material above the water jacket, the block isn't scrap. All of that is machined away and replaced- no big deal. This sounds like a classic D chunk failure. A crack starts on one side of a cylinder, and a little later another crack forms at an area usually perpendicular to the first. When this happens the two will work to connect, and when they do finally meet, the whole section breaks away and coolant pressure forces the broken piece into the cylinder bore. Collateral damages are usually limited to the effected piston, and it's connecting rod. We don't care about that, since we throw all those parts away anyhow. These things make a cylinder failure one of the best failures that we can expect, and it usually costs no more than an elective build; because, all the effected components are junked anyway. This one sounds textbook.

I wish that were the case but when I say the block is cracked - I mean literally the engine casing is cracked - there is about an 8inch crack in it on the bank 1 side of the casing around the power steering pump area right by where the cylinder let go.

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That's more extreme and not repairable. If you come my way I'll give you a block for free. I have one with 28k on it that lost an IMS and the block saw no damage.

Wow - I dont think I've ever been on such a helpful forum. Why have you got to be all the way over in Cleveland That would literally solve all of my problems as it looks like the crank and IMS on mine are fine. Would probably be cheaper to fly to Cleveland than go to Porsche but then again I dont think BA would be too happy if I put an engine casing in my suit case

Being in England, you may appreciate this. I brought a 1500 Cortina crankshaft back in checked baggage. Crank survived. Suitcase did not.

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If you do fly here, make sure you come into Atlanta, GA, not Cleveland, OH.

I had a friends wife who thought she was going to Jamaica with her sister as they got a 'great deal' - turned out it was Kingston Canada

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Just make sure you keep this handy list if planning a trip in the future: Paris, TX Moscow, ID Naples, FL Venice, CA Rome, GA Florence, CO Mecca, CA Edinburgh, IN Ayr, NE Lisbon, MD St Petersburg, FL Berlin, NJ Frankfort, IL Peru, IL Hamburg, IA Athens, GA Madrid, IA Amsterdam, NY York, PA Athens, TN Memphis, TN Paris, TN Cairo, GA (pronounced KAY-row) Cairo, IL Sparta, GA Bethlehem, GA Berlin, WI Brussels, WI Verona, WI Barneveld, WI Athens, WI Sussex, WI Cambridge, WI There's quite a bit more but these are some of the more recognizeable ones. I was in Australia awhile ago and visited Miami there too.

I just got back in the early hours of this morning from installing my daughter in Miami University .... In Oxford, Ohio. Stoo - sorry for your loss

I'm trying to source another block as we speak. I'm talking with Autofarm and will speak with Porsche directly tomorrow. The Autofarm 3.9 version is too much for me unfortunately.

Does "coming my way" means if you have the engine built by Raby?

Bit of an update after a long time. Finally managed to source a good second hand 3.6 engine which I am going to collect next week so fingers crossed I can get it back on the road again soon. If anybody needs any parts from my dead 3.6, let me know as I've stripped it right down.

Wow this was ages ago and I never updated the thread. So I rented a van and drive the 250 miles up to Wigan (UK) to collect the engine which was in great condition and had been scoped to check the bores. Also had 10k miles less than my broken engine. Got it all the way back with no dramas and set to work on it. Got it fitted in with no major dramas along with a new low temp thermostat, new drivebelt, oil filter, spark plugs, clutch, exhaust gaskets, all clamps, all new stainless bolts etc. It started first time and ran perfectly - only problem was bleeding the coolant as I got an airlock and couldnt get any heat through the vents. I fully drained in again and this time I mean FULLY drained it and refilled. Bled up fine and I've now done a good 500 miles plus in it and have finally gained confidence back in the car. Engine seems superb, no hesitation, no smoke and I'm enjoying being back in it. Since then I have also done new droplinks and ARB bushes (original Porsche) front and rear and have also just ordered brand new genuine front top mounts, caliper hard pipes all round and some Goodridge braided hoses which I'll do in the next few weeks. Next up going to get a new Apple Carplay ready Stereo (probably Alpine) and some new exhaust silencers. In the process of fixing the 996 I also bought a 986 for very good money as it was suffering from an overheat issue. That should also finally be on the road this weekend so all done in time for summer.

Good news and wishing you many happy miles! Any thoughts on why it failed in the first place? Or just bad luck? Volkert

I would say most likely D-chunk failure which allowed coolant to flood it, hydrolocked the engine causing the rod to snap. As the rod snapped, it hit the crank case with such force that it cracked it.

Nice to hear you found a new engine replacement and purchased a 986 as well.

Congrats on getting the 996 sorted! I hope you have many good years left with the car! And thanks for the interesting thread.