Reliability of 996 Engines

[JFP in PA]

I have, and I would definitely recommend against using a light weight single mass flywheel unless the rotating assembly, and the flywheel, are fully balanced as a unit before the engine is assembled.

A lot of people seem to think that they can simply slap on an X51 sump cover and all is well, when the reality is that the sump cover is probably the least important component in the upgrade.

dumb question here... what exactly is the rotating assembly... is that not on the flywheel... is it a separate component?

as for the X51 baffled pan.. its does provide *some* benefit that's for sure... but I definitely agree that it is only the 1st (and IMO necessary step) in upgrading the oiling system... I'm curious if there are folks who have done both X51 AND deep sump pan (which holds about 1/2 quart extra only) that have seen more stable pressures in corners where oil pressure was previously unstable. I know of an outfitter here in Canada that makes a sump kit that holds a *complete quart* of oil with spacing hardware and that would certainly help to ward off starvation a bit better than just 1/2 a quart; if the oil your engine needs is suspended in one corner of the engine during a high g corner it will never make it back to the sump and hence never pumped to where it is needed... (this is where complete X51 oiling kit comes into play - pumping it back into sump) and the theory of having a full extra quart means that it was never pumped and is ready as "reserve"... many are doing this but I haven't heard any feedback that shows a change in oil pressure; I have an X51 pan only and *think* I see a SMALL difference but I will do more testing this summer that's for sure as I have made less than scientific observations.

a lot of the oil trying to drain back into the sump gets "stuck" in the cylinder bank towards the outside of a given corner, and the oil in the sump stands up on the same wall of the sump. Not a good thing.

yes but I thought with x51 with the walls built in *around* the tube it forces a much smaller perimeter and keeps the oil in place during high g cornering so the pick up tube has something to suck in... it also has the baffles that open and close to trap oil in that little box round the pickup tube... in a non-x51 pan I can see the oil being cornered on the far wall away from the pick up tube but I don't believe this is happening with x51 pan... unless of course that corner is so long and sweeping and you are generating serious g force for a long time so that it picks up all the oil the x51 pan has collected and now its stuck on top of one of the heads waiting for the g-forces to stop so it comes back down... <- that can definitely happen and from what I'm told will blow the motor; so the question is whether putting in an extra litre of oil with a deeper sump pan makes that condition less likely and I think it does..

btw ... I never knew the x51 pan with baffling allows an extra 1/2 litre of oil... interesting...

All M96/97 motors, down to the lowly 2.5L have fully baffled sumps with trap doors to limit oil movement right from the factory. The X51 (first photo) is a bit deeper and more elaborate, but very similar to the base system as seen here (second photo):

Edited April 14, 2011 by JFP in PA

[hoacha]

Just hit 159,000k on my 2002 C4S (with Tiptronic).. Still runs perfect, never changed anything motor related except the ignition coils. I get an occasional puff of white smoke after starting it, but it only happens maybe once a week..weird... I run it hard and dont baby it. cheers.

[chriswaxman]

Could the 996 be one of the most reliable cars on the roads today? (Or at least the German roads?) The TÜV says yes.

This has been puzzling me for some time. . . It seems that according to the German TÜV (Technical Inspection Associations) M96 engined cars are amongst the most reliable cars, period. Compared to all cars. And this trend continues several years out from purchase -- not just initial quality.<br id="yui_3_2_0_4_130634284081990" class="yui-cursor"> See:

http://www.autobild.de/artikel/auto-bild-tuev-report-2007_59351.html

This site seems to have several years worth of data: http://www.anusedcar.com/

Take, for example, the 2005 report of cars 4-5 years old, which would seem to cover 1999-01 911 models

http://www.anusedcar.com/index.php/tuv-model/porsche-911

The 996 comes in 8th overall, ahead of the Toyota Corolla. Other years it comes in around the same. And for the 2007 report on cars 4-5 years out the 996 comes in first. First overall, of ALL cars.

The Boxster does really well for all years too, including several 1st place finishes.

This one reads like a Porsche press release, but still: http://www.autoracingdaily.com/news/industry-news/porsche-offers-supreme-long-term-quality/

Is it simply that the cars are close to perfect except for the the occasional catastrophic engine or transmission failure? Am I missing something? Why have I not seen a single mention of the TÜV reports on the lengthy threads on 996 reliability on several very active 996 boards in the US and UK? Maybe I'm more tuned in to TÜV because I work for a German company (not a car company). Really though, I just took a flier and Googled "Porsche TÜV" and found this.

I don't mean for a minute to diminish the pain suffered by those whose engines have gone south on them. Common or uncommon, that sucks. And it clearly happens. I'm just having trouble reconciling the reputation that these cars are building up on the internet with what appears to be actual reliability studies by an authoritative organization.

Thoughts?

[cbzzoom]

Is it simply that the cars are close to perfect except for the the occasional catastrophic engine or transmission failure? Am I missing something? Why have I not seen a single mention of the TÜV reports on the lengthy threads on 996 reliability on several very active 996 boards in the US and UK? Maybe I'm more tuned in to TÜV because I work for a German company (not a car company). Really though, I just took a flier and Googled "Porsche TÜV" and found this.

The TUV results have been posted often on popular Porsche forums. It certainly makes Porsche look good, but it has basically nothing to do with reliability. Obviously if you have an IMS failure or a D-chunk failure, or a scored cylinder, or an AOS failure, or a rod bolt failure, or a snapped shift linkage, or broken water pump, or cracked coolant expansion tank, or any of the other many failures that afflict modern Porsches you simply won't take your car in to the TUV office for inspection. It does seem that most of the M96/97 failures are of the rare/catastrophic variety. (the only exception is the RMS leak which many people have and live with, and that could possibly be detected as a failure if it was bad enough)

So clearly TUV results have absolutely nothing to do with engine failure rates.

The TUV results do reflect that Porsche owners on average take very good care of their cars. Things like worn brakes and tires are failures under TUV and Porsche owners are much more conscious of those things than the average car owner.

There's a similar kind of statistic that gets bandied around that the older 911's have a higher percentage still in operation than any other (mass market) car make. Some people incorrectly use that to suggest that the old 911's are very reliable. In fact it just means that they are well loved and the owners keep them running. Anyone who thinks an old 911 is more reliable than an old Honda Civic is quite delusional - but when your old Civic starts making funny noises, you just ignore it, and your old 911 goes in for an engine rebuild.

[chriswaxman]

Obviously if you have an IMS failure or a D-chunk failure, or a scored cylinder, or an AOS failure, or a rod bolt failure, or a snapped shift linkage, or broken water pump, or cracked coolant expansion tank, or any of the other many failures that afflict modern Porsches you simply won't take your car in to the TUV office for inspection.

I was under the impression that TUV statistics were compiled based on defect claims, is it the case that an owner must take his car to a TUV office to be inspected? Even assuming that is true, why wouldn't an owner do that?

In a similar vein, Edmunds gives the 1999 911 the highest reliability ratings in all areas, including Transmission and Driveline. Edmunds' results are claimed to be based on "Indentifix." "Reliability Ratings by Identifix is based from repair shop-reported issues."

http://www.edmunds.c....html?sub=coupe

More on Identifix from MSN Autos: http://editorial.aut...atingsinfo.aspx

And similar results on MSN autos:

http://autos.msn.com...911&trimid=3036

At any rate, the reason I post this is because there is the thirst for "numbers" on 996 reliability and here are some organizations that appear to have compiled information based on large sample sets. There may be some issues as to what is reported, but at worst its no worse than random samplings of internet forum posts.

Again, I don't mean to suggest that "IMS failure or a D-chunk failure, or a scored cylinder, or an AOS failure, or a rod bolt failure, or a snapped shift linkage, or broken water pump, or cracked coolant expansion tank, or any of the other many failures" don't exist. Clearly they do. My car has experience the cracked coolant expansion tank and had a transmission bearing issue. And I do not mean in any way to undermine the legitimate bad feelings of those who have suffered failures, myself included.

My point, rather, is that the 996 seems to get an unduly bad rap. The only objective statistics I can find show it being quite reliable overall. All cars have problems, including many other Porsche models. But it seems the 996 is singled out to a degree that may not be warranted.

[2003996C2]

We have several customer's running the Accusump system, some which we installed. Is there something specific you want to know?

Two things:

Where have you mounted them?

What pressure do you them for?

I'm new to forums. Do you own / work at a Porsche repair or engine building business. I ask because of the reference to customer's cars. Thank you.

[DanSteel996]

Hi, I'm new to the forum ... Hello everyone!!

Picked up my 99 C2 about 3 weeks ago and it spent more time back at the dealer where I purchased the car from. The PPI detected leaking spark plug tubes which were repaired. As I was driving the car home, the temperature gauge’s light started blinking ... apparently the car was overheating. Also, an oil leak was discovered in my garage which the dealer looked after. Back to the dealer it went ... apparently, the coolant was low 2 liters. He told me that one of the tube/hose situated at the firewall was the culprit.... an $18 part plus over $200 labour.

Today, I discover another leak ... coolant! I left the dealer another message and will have to schedule another trip there. Good thing I put a white cardboard under the engine to monitor leaks. I'll admit that the dealer has been wonderful in responding to the problems. However, in the 3 weeks that I have since taken possession of the car, we have driven the car ... at most 3 days. Only wish I could enjoy it more especially when the warm weather is here.

Not sure why you bought the car if it showed such such deficiencies. If there was nothing other than the plug leaks reported then your PPI guy screwed you. You do NOT have the problems you did in a week after a PPI that was satisfactory.

Remember though, that you have a 99. Coolant leak? Water pump or cracked coiolant reservoir I assume which is NOT b/c of an unreliable motor. Leaking spark plug coil packs is another age issue. We've all had them replaced. Sure hope you don't have to replace your air filter as well 'cause that might just send you over the edge.

Key to understand is this car was sold en masse unlike other P-Car models. You see more problems voiced b/c there ARE more cars out there. It is MUCH MORE EXPENSIVE to take care of a 993 than a 996. You want reliable bulletproof? Get a GT1 derived motor ala GT3/TT. There is a reason there is a price disparity between them and the "regular" Carrera's.

Hopefully, you are now on our way (when you get your car back) to some rewarding ownership :thumbup:

Hi, I'm also a newbie to this forum. Just got my beautiful '99 996 C2 3 weeks ago. 90K miles, very clean, carfax & PPI checked out good. This car runs great, no leaks & has very few problems. I love it! I guess I got lucky, at least it feels that way right now. I had a post PI from my indie mechanic. He said I did good, but warned me about the IMS bearing assy failures that are common with 996's. I'm planning on getting it replaced soon.

[JFP in PA]

We have several customer's running the Accusump system, some which we installed. Is there something specific you want to know?

Two things:

Where have you mounted them?

What pressure do you them for?

I'm new to forums. Do you own / work at a Porsche repair or engine building business. I ask because of the reference to customer's cars. Thank you.

In the rear boot.

Slightly above max oil pressure ~60-80 PSIG.

Yes, I own a business.

Edited July 16, 2011 by JFP in PA

[eidolon]

Well in light of my new thrust shim issue on my 2001 996...my engine is toast and I have to replace it. I am curious of others that have driven down this road on the M96 engine.

[logray]

In watching these forums since 2006, yours is the first I've read about. Not saying that they haven't happened.

[RSrocket]

I own a 99 996 6 speed (non e-gas) with 96,xxx miles. I'm not new to Pcars but a newbie to the 996. I'm aware of the problems that the M96 engine has and budgeted that into my purchase (minus having to replace engine).

I recently got a loud chain rattle and slapping noise from the right side (bank 2). I replaced the chain tensioners (minus the rear one) and so far all is good. But, after the car has warmed up, I do get a slight ticking noise from bank 2. I believe it might be a bad VarioCam / solenoid going bad. From my understanding those are parts that eventually need to be replaced.

I will replace the clutch, IMS bearing, & the RMS seal soon. I would like to make it a DIY project, but I don't have the space, know how, or the confidence :( Am I taking the right course of action to make her a car that is a reliable daily driver and most of all make her a car that is a keeper :renntech:

Edited January 7, 2012 by RSrocket

[Thklinge]

The first posts, back in 2005 of this thread is really funny to read today. M96 a reliable engine? Seriously? I thought I had enough to worry about with RMS/IMS/AOS. I've dodged all of them for almost two years, then it turned out that my cylinders were oval and I got cracks in the cylinder walls. Then there's cylinder scoring on the newer 3,6 and 3,8 engines, and so on and so forth. A company here that specializes in rebuilds (including boring and installing Nicasil cylinder liners) says it like it is, and adds a final three-syllable abbreviation to the engines: POS. The current record from new to scrap metal is 18.500 miles... My car failed 3700 miles after a Porsche dealership had it in for a major service and said it was in perfect working order.

I'll never own a 996 Carrera again. In fact, there was a long period of time when my car was in the shop and the bills kept piling up that I swore I'd never own another Porsche. I'm still kinda weary, it seems Porsche has discovered the magical revenue-maker called "planned obsolescence". I might go BMW, or Porsche turbo, we'll see when I get this car off my hands. Hopefully before the new engine disintegrates on itself... Reliable my ***.

[987_RDC]

Then there's cylinder scoring on the newer 3,6 and 3,8 engines, and so on and so forth.

I assume you are referring to the 987 and 997 engines, how do you test for that? Leak down? What other issues are there to look for?

[Rik Tytgat]

I had my nr 6 scored on my 2005 997 earlier this year. The engine made an atypical ticking noise, and consumed about a liter of oil every 1500km. Within spec, but after the repair (new short block and pistons) I never had to add oil. I also noticed more smoke from the left exhaust (right bank).

This is how the piston looked:

Edited July 12, 2012 by Rik Tytgat

[c70Pete]

I had my nr 6 scored on my 2005 997 earlier this year. The engine made an atypical ticking noise, and consumed about a liter of oil every 1500km. Within spec, but after the repair (new short block and pistons) I never had to add oil. I also noticed more smoke from the left exhaust (right bank).

This is how the piston looked:

_DSC9852.jpg by Rik Tytgat, on Flickr

thx for sharing..... what was the mileage on your car and how often to you take it to the track? this looks like cylinder looks like a tracked vehicle with no cooling and long oil drain intervals..... curious as to what oil you were using.... full disclosure... I had the same thing happen to my 99 996.... ticking with scored cyliinder and huge oil usage..... ended up buying a new motor.

[Thklinge]

Hartech has 72 tightly written pages about cylinder scoring in 996 3,6/997 3,6 & 4,8 and Cyman engines: http://hartech.org/docs/buyers%20guide%20web%20format%20Jan%202012%20part%205.pdf

[Rik Tytgat]

It had about 110.000km when I took it to the independent Porsche specialist that eventually repaired the engine. Although I did track the car twice, I assume the damage had already been done when I bought it at about 85.000km, since I had to add oil since I bought it. Of course, I don't know how the car was used/driven by its first owner. But it did get worse during my ownership, the ticking noise wasn't there (or at least I didn't notice it) at the beginning.

The oil: before the engine repair: Mobil1 0W40, since the repair (the indy always uses it) Mobil1 5W50.

I ALWAYS waited for the oil level test to finish before driving the car, and I topped it up whenever it went to 1 block above the minimum level. I didn't drive it fast when cold, I really took good care of it.

What I also did: change the thermostat to the LN Engineering version that opens sooner.

Bottom line: I'm afraid it will break down again after another 100.000km. When I browse second hand Porsches online, I often encounter cars with "new engine, only xxxxxx km" on high mileage ones. And I will not track it anymore!

[c70Pete]

It had about 110.000km when I took it to the independent Porsche specialist that eventually repaired the engine. Although I did track the car twice, I assume the damage had already been done when I bought it at about 85.000km, since I had to add oil since I bought it. Of course, I don't know how the car was used/driven by its first owner. But it did get worse during my ownership, the ticking noise wasn't there (or at least I didn't notice it) at the beginning.

The oil: before the engine repair: Mobil1 0W40, since the repair (the indy always uses it) Mobil1 5W50.

I ALWAYS waited for the oil level test to finish before driving the car, and I topped it up whenever it went to 1 block above the minimum level. I didn't drive it fast when cold, I really took good care of it.

What I also did: change the thermostat to the LN Engineering version that opens sooner.

Bottom line: I'm afraid it will break down again after another 100.000km. When I browse second hand Porsches online, I often encounter cars with "new engine, only xxxxxx km" on high mileage ones. And I will not track it anymore!

You can track just cool off when your temps come up and change that oil every 4 track events. Mobil 50 is better than 40 but castrol 5-50 is also good stuff. Better than Mobil IMHO

[Fierofly]

2003 C4S 64K IMS Failure, One owner, one dealer serviced. Had appointment to get IMS bearing replaced Jan4. Bearing let loose on, of all days Dec 21 2012 at 45mph. Now it's mine and will get an LS3 transplant.

Listed on E-Bay http://www.ebay.com/itm/Porsche-Engine-3-6L-996-C4S-2003-64K-miles-IMS-damaged-/271159787742?hash=item3f226200de&item=271159787742&pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr

Edited February 21, 2013 by Fierofly

[PeterC4]

Jim Pasha has written an outstanding article in the October 2005 issue of Excellence Magazine. He discusses the overall reliability of 996/986 engines and what makes these engines some of the best Porsche has ever produced. We have added the 26 high resolution pictures showing the 996 engine internals.Thank you to Jim and Excellence magazine for allowing us to reproduce this.You can download the PDF version of the article here:attachmentMembers can view all 26 pictures - most not in the article.(You will need a browser that has the Flash plugin to view these pics) here(edit - added pictures link Sept. 27, 2005 - Loren)

Of course, it all depends on how long you measure reliability.

[brendel]

It had about 110.000km when I took it to the independent Porsche specialist that eventually repaired the engine. Although I did track the car twice, I assume the damage had already been done when I bought it at about 85.000km, since I had to add oil since I bought it. Of course, I don't know how the car was used/driven by its first owner. But it did get worse during my ownership, the ticking noise wasn't there (or at least I didn't notice it) at the beginning.The oil: before the engine repair: Mobil1 0W40, since the repair (the indy always uses it) Mobil1 5W50.I ALWAYS waited for the oil level test to finish before driving the car, and I topped it up whenever it went to 1 block above the minimum level. I didn't drive it fast when cold, I really took good care of it.What I also did: change the thermostat to the LN Engineering version that opens sooner.Bottom line: I'm afraid it will break down again after another 100.000km. When I browse second hand Porsches online, I often encounter cars with "new engine, only xxxxxx km" on high mileage ones. And I will not track it anymore!

Hi Rik,

Your post sounds exactly like what happened to me, my 997 C4S tiptronic was always serviced wtih 5W50 at Porsche ( 137 000 KM)

At the last service, I had to change Porsche garage due to schedule issues and I noticed they put Castrol 0W40 ( approved oil...)

Shortly after, 1 month, I got the ticking noise and it got louder and louder on the right bank 4-5-6 , an oil consumption of 1L every 1000 KM, normally I was doing 1L every 6 to 7000 KM+ a lot of carbon black on the left exhaust

I went back to the garage that did the service ( knowing damned well what happened after reading the great article from Hartech) and they told me it was a hydraulic valve lift. Since I had a guarantee from Porsche, I decided to see another Porsche center for a second diagnostic, before I finished explaining to the guys that I had a ticking noise, the man interrupted me to say: " and you a black exhaust pipe and using oil", he mentioned that this is rare but happens and they will replace the engine for free

Took a month to get the car back, they had to do a borescope picture, get porsche appoval, messed up schedules...

The engine was delivered with everything new on it, generator, oil separator, intake manifold, water pump, .... even the exhaust manifold, ( i heard that the engine is tested at the factory before being delivered )

anyway, to my point, when I got the car back thanking the chief mechanic with a box of chocolates, the guy told me, please now only use Mobil 1 5W50. I guess this comment was not innocent

I read the hartech article and I have to say, it did sound scientifically bullet proof, but my car is a tiptronic with the third radiator so the cooling capacity is in theory higher and I was not expecting it to had score cylinders

When I read your post I am more thinking that the scoring cause is the break in the oil film, one may say that this is a consequence of a too high cylinder deformation caused by heat but I guess the 0W40 is too thin, and it might happen sooner than with the 5W50

I think the 3.8 has a real desease, though the we don't hear IMS issues, it seems that every car with high mileage on the net had the engine change done

Looking at prices of 1 gen 997 carrera S today, well less than 40 000 euros, and knowing an engine rebuild will ensure you another 100 000 to 150 000 KM trouble free for 7 to 10 000 euros, it is still worth the money to me

I would like to mention also that when I had the cylinder scoring, I reved up the engine just like before, besides the ticking noise, and oil consumption the car was running perfect

[valfam]

What do they mean by contaminated fuel?

[Sl3ipner]

What do they mean by contaminated fuel?

Good question (contaminated fuel as mentioned in Pashas article: http://www.renntech.org/forums/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=3224

[krazyk]

I know JR's book is due out in a few months and I hope he includes some of the best things the M96 owner can do to increase reliability. Without going into the MOF's or CEF's list I would like to see at least a "top 10" list or something.

[Thklinge]

Top 10?

* Drive it like Porsche meant it (use revs, but on hot engine only)
* Swap engine oil yearly

* Follow Porsches maintenance program.

That will be the best you can do and the first one will reduce the chance of IMS-failures. As for oval cylinders the only solution is to send the engine in for a cylinder reinforcement.