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YOUR RESEARCH996 Engine Failure? Looking for confirmation
Leading reported evidence
Check air oil separator
Performed · outcome unconfirmed
No successful repair reported for this finding.
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Performed · outcome unconfirmed · Original poster
I checked the AOS when I replaced the starter and starter cable.
Leading evidence: 'Check air oil separator' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'cracked cylinder or cracked head' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Check air oil separator' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Performed · outcome unconfirmed · Original poster
LN engineering retrofit + clutch was replaced ~21,000 miles ago.
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Performed · outcome unconfirmed · Original poster
I checked the AOS when I replaced the starter and starter cable.
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Performed · outcome unconfirmed
Id say his best bet is to drop in used engine and try to sell whatever he can from old engine.
Check full cylinder head job, main brgs, rod brgs, gasket
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Suggestion
Rebuilt motor : 3.6 ltr, case disassembled cleaned and checked, full cylinder head job, main brgs, rod brgs, gasket set, chains, chain rails, pin chain wheels, IMS brg installed, new rings if needed, new AOS, fuel injectors cleaned and serviced, lifters replaced.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
63 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
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Outcome without a verified action link
As bad as the issues are with these engines breaking, it�s still not common, or even close to 50%.
Hey folks,
Pains me to write this post out but I fear the worst and I am looking to see if anyone has any good news for me.
About a month ago I took my 02 Cab in the mountains for its last spirited drive of the year before I listed it for sale. I got a cylinder 3 misfire code on my drive to Skyline Blvd. It should be noted that I replaced spark plugs and coil packs less than 3k miles ago. Not making much of the error, I cleared the code and proceeded with my mountain drive and didn't experience any further issues. Car drove well. I finally decided to list the car for sale a few weeks later. I drove the car spiritly (once it was up to temp) at highway speeds. After sitting the car wouldn't start. I tried. Eventually, on my last try, the car started for a few seconds then died. It also released a ton of smoke from the passenger tailpipe. Towed it and planning to use a borescope to take a look into the engine this weekend. Wanted to get some thoughts / advice from the community before hand.
My suspicion is there is a crack in the cylinder head. See below for hypothesis.
Smoke came out of the passenger side tailpipe which indicates an issue with the cylinders on the left bank of the engine (cylinders 1,2 and 3)
Got a misfire code a few hundred miles before this happened on cylinder 3
Coolant in Reservoir is now empty (where did the coolant go? Likely in the cylinder head)
Likely not related to any components which assist/related to starting the vehicle. I replaced the starter motor, starter cable, crankshaft position sensor, ignition coil packs and all spark plugs.
Likely not an IMS failure. LN engineering retrofit + clutch was replaced ~21,000 miles ago.
It could be a cracked head or cyl.
Have u checked the oil? I would drain it just to be sure.
If its just the head its pretty resonable cost wise to fix.
I doubt its as bad as mine
If it does not even start, that is pretty bad news. I think some serious diagnostic is required
1. Remove and inspect plugs
2. Compression test
3. Leak down test on that one low cylinder
4. Smoke test the intake side
5. Drain oil and look for bits
Then, if needed, drop engine and disassemble.
That is unfortunate you have this right before the sale. But ... it would be extremely bad for the buyer to have this right after. The finger pointing would never end.
Yeah I really feel for OP but could you imagine something like that occurred on a test drive. Sucks for both of them!
Curious what the investigation is going to uncover.
Yeah, check oil filter housing and filter. Cut the filter in half. Scope cylinders if ya want to. Probably cracked head based on the scenario. I just did a motor swap myself. Not cheap, but definitely fun. When was list time AOS was checked as well?
Appreciate the responses - I agree with the general sentiment here and I'm glad this happened to me instead of a new buyer taking the car out for their first weekend drive and it blowing up.
I checked the AOS when I replaced the starter and starter cable. There was very little oil in the plenum. So don't think its related. Also AOS shouldn't affect start-up and is typically gradual (smoke on startups). Will definitely drain oil / drop oil pan on Sunday.
I also laugh sometimes when I think about the $10k in profit I just lost
996 ownership is equivalent to playing the lottery. I bought this car in somewhat rough mechanical shape. I wanted to make it perfect but in that process kept it longer than I probably should have.
Any sign the water pump is leaking? Was the water pump replaced anytime recently after the original pump failed?
I'd definitely drain the engine. If there is coolant in the oil (which I would expect considering there is none in the reservoir), I wouldn't both with doing any further diagnostics or trying to run the engine further. It's going to have to come out. As a previous poster mentioned, it's likely a cracked cylinder or cracked head.
Water pump and thermostat was one of the first repairs I had to do on this 996 as it failed on a normal highway drive. Was replaced approx. ~5k miles ago.
Then I'm pretty sure it's a cracked head. That's why I asked. Depending on how long you've been driving it with coolant intrusion into the crankcase will determine how much damage was caused to the engine internals. I'm not sure that simply replacing the heads will solve the problem.
I know I'm getting ahead of myself here without full confirmation - assuming its a cracked head.
My goal here is to minimize loss (monetary) reason being is I really don't see myself enjoying long term ownership of this particular 996. If I had the disposable income, I may have considered converting this into a track capable car but would prefer a coupe instead of the chassis flexing cab life.
Options I'm considering:
Send car out for engine rebuild $15-20k. Probably worst option from a $ perspective. I wouldn't get too much more on the market for a rebuild unless i opt for the 3.6 -> 4.0 upgrade.
Drop engine and ship for rebuild $10k? I'm not really sure on cost as I haven't seen many threads about people doing this definitely need more info. My guess is it would just move me sideways.
Sell as a roller. Anyone have any thoughts on current market value? 02 cab with 84k miles. New PS4S, 18" wheels, brakes have good life, paint is 7.5/10, interior 7.5/10, ims and clutch serviced, new engine mounts, starter, starter cable, fuel sending unit, water pump, good documentation and a few other items serviced.
Yea its unclear. I believe the original CEL I got for the cylinder misfire was approx 250miles ago. So perhaps slightly before that is when it could have started. Prior to the incident, I hadn't checked the coolant reservoir tank in quite some time so I'm lacking visibility there in my root cause analysis.
If your goal is to minimize the financial loss then selling your 996 as a roller is your only option.
You will never recover any of the money you invest from this point forward.
Eh kinda depends. 996s have gone up in value, but rollers havent much from what ive seen. Id say his best bet is to drop in used engine and try to sell whatever he can from old engine.
Maybe not a junkyard motor�
You Tube
For the OP - I would think a used M96 is the most economical way out of his predicament if the motor in the car is toast.
OP - what�s the oil look like ?
I had a friend who blew the IMS on a 996 and he opted for a $9K rebuilt engine swap. That was 5 years ago and he is still driving the car. The car was in good shape so it was worth saving. As for this car, I think a cracked head repair is $5K? A swap with a rebuilt engine is $10K-11K? I would avoid a used engine. You never know what devil you are gonna get.
That's precisely my fear as well. Beyond that, it would be nice future where there aren't "996 engine failure..." posts like mine and swapping a used one could very well be kicking the can down the road.
Looks like you are now down to only two options.
1. Sell it as is and take a loss.
2. Or get it rebuilt, assuming the damage was not catastrophic. The question is then whether you do it yourself for under 15k or you find an engine builder that will cost you 15-35k.
Lemonade out of lemons?
Thats true, but remember, the default experience for these cars is the engine does not fail and works just fine. As bad as the issues are with these engines breaking, it�s still not common, or even close to 50%. So the smart money, if you are a risk taker, is buy a used engine that�s been inspected, and chances are, it will work just fine.
It�s true that eventually, with enough cold starts and hard miles, these engines will eventually need to be rebuilt. But most engines from other car markets are no different. So again, a used engine might sound like a gamble, but the gamble is in buying one sight unseen without an inspection.
I have already run into two of his engines. Both people I spoke with were happy. Looking at what used engines are going for I would buy one of his rebuilts. I also spoke with Joe personally, pretty cool guy, even told me to drop by
if I was over there. He also sells a Ton of Porsche parts pretty reasonable prices. Unless you just have a cracked head.
^^^ For $10.5k or $11.5 k what does �rebuild� mean? My understanding is that $10.5k just about (maybe not even) covers the parts needed to do a proper rebuild... Is Joe building these motors for free (no charge for labor?)? Maybe he�s fabricating all the new parts in his back yard? Something doesn�t add up in that price - caveat emptor!
Alex at 9xx also is close to those prices. The more I get to know Porsche guys in the club I find more and more options at reasonable prices. As an example I did this in March, I�m in the Houston area. 5 shops, replace AOS and hoses parts included. One shop $2600 and it was not a Porsche dealer. Most affordable was $975 and it also included replacing serpentine belt. That shop also basically did a free post purchase inspection on my car. The manager also told me about all other mods I didn�t know I had, rss, konis, hr, fab speed, straight car bent driver side rear wheel. There are deals to be had , you just have to shop. Right now I just paid $375 for 2 continental ssr run flats 225/50/17 with 40,000 miles prorated warranty included, life time balancing and rotation for my wife�s Mercedes. Now I negotiated that yesterday with the mgr and I have been buying tires from him at discount tires for 20 years.
Sounds like the rebuild includes :
Rebuilt motor : 3.6 ltr, case disassembled cleaned and checked, full cylinder head job, main brgs, rod brgs, gasket set, chains, chain rails, pin chain wheels, IMS brg installed, new rings if needed, new AOS, fuel injectors cleaned and serviced, lifters replaced. That's the quick and dirty explanation given by their site. I'm sure you could add to that if you want to but could be a viable option for someone not wanting or able to do a $25k+ build.
seems they hope to find case halves with no scoring and then just use the old rings to help ring seal with already oval cylinders. Limited machine work on the case halves and not needing pistons certainly accounts for a big part of the cost savings, but seems pretty half assed.
not certain about what you call Half assed. But if you look at drop motors with 115 to 125k miles for $9,000 this makes a lot of sense
for Me. The heads have
5
angle jobs.
taking a motor of unknown mileage and reusing the rings seems half assed to me. You can feel free to disagree. Putting new rings into an oval bore is also half assed.
compared to a 9k take out motor, this could potentially be better, or worse, depending how the work was done .
Also, who knows if this engine requires a core charge, which can be as much as 4k
I�m pretty good managing money and making money related decisions. I am not going to force my decisions or opinions on anyone, what I can tell you is that for 8 years, fidelity, vanguard, fisher and a bunch of others have wanted to manage my assets and when we sit down and do an apples to apples 5 year return evaluation they can�t beat my returns. since I dealt with people from over 110 countries worldwide, I learned that is always easier with OPM ( others people money). Anyway, on my car we are going to do a leak down, compression test, and reruns the cam deviations, fuel trims, plus pull the plugs to make a fair evaluation of the condition of the engine. It runs great feels strong, accelerates hard and I�m approaching 7,000 miles of ownership. Just want to know where I stand at with this motor, and again I ain�t going to track it, I�ll take it supersonic every chance I get.
Like I said you do whatever you want to do. I�ll make a decision, post the results and let the gallery decide. At the end of the day is whoever owns the particular car decision. Remember I had engine builder racing experience, engine lab testing, tearing apart motors and ratting them for deposits, sludge , ash whatever the parameter where. Yes I�m not an M96/M97 engine expert. I have my basics covered.
One of these days, we will need to update the spreadsheet that originated a few years ago about rebuild options. More shops are coming out of the woodwork offering various options for lots of situations, and there are plenty of situations, including get it running and sell it. Certainly not my choice as a seller or buyer.
Quite frankly, there are more options today than ever.
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that�s a good result and makes me feel like I�m in excellent shape. With taxes and what work I have done to my car I�m at less than 20k. It�s a coupe with 408s . Anyway, we just don�t know what was done to my engine. It�s running top notch , squirrel 🐿 hook it up to the durametric Saturday and everything is great. We believe by the mileage definitely at least the chain pads etc were already done. The IMs, rear main and clutch were done like 33000 miles ago.
Flat 6 Innovations gets reports of these types of failures daily. That's why Jake strongly recommends getting a pre-purchase inspection. The 996 is still the best 911 value, but at 22+ years old, inspecting the engine is vital with any purchase. And, I'm not talking about popping the rear deck lid and pointing a flash light into the engine bay. I'm talking about checking camshaft deviations, rough running index, over-rev report, readiness status, manometer test, fuel trim, sump inspection and even scoping the cylinders.
OP, sorry for the loss. Sucks. You're not alone. Happens a lot. Unfortunately.
Found a couple or relevant posts from other threads that are worth adding to this thread:
And then the one that puts it all into perspective about PPIs and the current market:
Work_truck makes a great point about how it's difficult to even get a seller to do a PPI in today's market given the demand.
Thanks for the words of encouragement. I originally bought my 996 C2 from the money I got from my stolen BMW S1000RR (back when prices were reasonable for 996s). While I have always been interested in sports cars and followed the scene very closely, when it came to ownership, I always saw motorcycles as a better value proposition for the experience I was looking for. My time driving my 996 and various other 996s, 987s, 997s has really opened my eyes about future Porsche ownership. It was a heck of a journey for the two+ years I owned it. I racked up about 6K Miles and definitely never babied it. I also leveled up my gear wrenching skills considerably which can be carried over to other aspects in my life. I'm out of the game for now and will be back on two wheels for my next "for the weekend" purchase. However, I feel my hiatus from Porsches is only temporary and I see myself sitting behind the wheel of a now dying breed of NA 911s or a Cayman in the near future.
some cars you can buy without ppi. I did, the price was right. There were 42 out of 43 maintenance records done at Porsche dealerships in California and Arizona car fax with such details as clutch, rms, IMs, brake flushes, coils, spark plugs, water pump. Face time cold start and look around the car. Wisconsin requires car dealers to provide a mechanics report. Now that was an $18000 Porsche with 91000 miles. 3.4 engine. I may be interested in a 997 carera s with a 3.8. Now that is a $50,000 car and a 3.8, so that is completely different proposition.
I've always heard, "A fool and his money are soon departed". This can be very true with buying Porsche cars. When you rap high demand and brand attractiveness in the equation, many people get burned.
I understand some sellers don't want to bother with scheduling a PPI, but high demand for these cars should never cloud one's due diligence. Jake Raby and I have been planning a "buyer's guide" for M9X based Porsche cars. This would be the alternative to paying for a PPI in cases (e.g. auctions) where it's not possible. If we can establish there is enough demand for such a video, then it will happen.
We've put together a few downloads to help perspective buyers:
https://lnengineering.com/education/...a-porsche.html
https://lnengineering.com/education/...endations.html
I may be buying a 997.1 Carrera s. My main concern with that engine is bore scoring, other than the usual suspects anything else I definitely need to check for?? Thanks once again.
This is a source reference. Confirm exact model applicability in the original material.
