The question no-one wants to ask. Ever.

What is this engine noise? At least that's the question I didn't think I'd ever have to or want to ask. I purchased a 2001 996 right at one year ago with 89K miles on the clock to do some R&D for my line of exhaust systems. My wife latched onto the car immediately and never let go. We both just love it. It has a tip trans so she can drive it easy in the hills and mountains where we live. Car is driven easy by us both and now has 92K on the clock. I drove my daughter to work yesterday, came home and parked the car, loaded up a couple boxes to run to FedEx and then hit the key to start it. Car started quick then died. Very odd. Hit the key again, same thing. Cracked the throttle and hit the key and it stayed running but had a fairly loud metallic clicking noise out the exhaust that followed engine RPM. I let it run for several seconds to really listen to this sound then shut it off. No warning lights came on during this time. I have a hunch what it MIGHT be but would like to see what you guys who have owned these cars longer think. In all my decades of owning air cooled Porsches I've never had an engine failure. I thought the world of this car until today. It had become my favorite to drive, even took it on a 1000 mile trip a few months back. The noise is different this morning. A lot less noise and not as melodic in following the engine RPM. Here is a video, what do you think?

Hard to say. But if you have never changed the accessories belt tensioner or idler, then I would start with those. If not those, then listen to and look at chain tensioners.

Chain tensioners or lifter failure was my suspicion, did not consider accessory belt tensioner. If the latter is the problem how does it cause this noise?

I found a video that has the exact same noise I heard when the problem was fresh. https://www.bing.com/videos/search?q=996+lifter+failure+noise&&view=detail&mid=B5A60C654745D6BBC3DAB5A60C654745D6BBC3DA&&FORM=VRDGAR Lifter failure. Now to see exactly what that means in one of these cars ...

Failing IMS bearing. Check the oil filter. You will lose less than a quart of oil. Cut the top and bottom off and spread it out.

The IMS bearing was checked when I bought the car a year ago and found to be in good condition so we did not change it. Everything works 'till it breaks of course so it could have given up after the inspection. That's a (relatively) cheap fix, would be happy if the IMS bearing is the issue. Worst part of that deal is the 12 hours in and out to pull the tranny again.

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Yeah check oil filter 1st, if all good there drain oil & remove sump plate to inspect. If it is lifters I have a set of low mileage tested & cleaned for sale, or I also have a rebuilt 2001 engine with 3.6L pistons & sleeves for sale for an upgrade.

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Hardly a cheap fix - by the time the IMS shows its ugly head in the engine, via noises, debris in the oil, etc, your engine is already toast. Putting an LN bearing at that point is a waste of time. That fix needs to be done before anything breaks or wears out. It does not cure the damage that has already occurred. sometimes, the block can be flushed to remove all of the metal particles that have gone through all of the inte5rnal passages but the scoring and grinding will not have been cured. That sound could be lifters, or it could be from bore scoring, or it could be from tensioners (that's my guess btw). Regardless, unless you do your own work, I would not start it up again until the shop has it and can properly diagnose it. Every time you start it, you could be making whatever the problem is much worse. Good luck and I hope it isn't too serious. It's a nice looking car.

Yes if something is chewed up in the engine that's a whole different ballgame. Whatever it is sounded a LOT worse when I first heard it (engine warm) then when the video was made the next morning (engine cold). The second video I posted that I found on line is how my car sounded the first time I heard it. There was no warning at all, ran terrific sounded terrific. Shut it off then restarted and it had an immediate heavy metallic tick that followed the RPMs. My first guess was tensioners, then I did some internet searches and all these lifter noise videos started popping up with the same sound I heard. Yes the car is beautiful inside and out. I absolutely love it but if they are this delicate I'm done.

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Hmm, maybe a 997.2? I understand they are best of breed - none of the IMS issues, and unlike the later/newer 911s, still have some soul. Plus they do look great.

The 997's are larger than the 996 which is one thing that pleasantly surprised me about the 996. It really had a very familiar 911 feel to it, only modern. I've driven 997 and 991 and they feel really bloated and heavy to me. Very disappointed in this. For the past year I have been singing the praises of the 996 to anyone who would listen, now I have egg (motor oil?) on my face. Right now I'm leaning heavily towards selling it as-is and be done with it. Will contact BYprodriver to see what a replacement engine costs but right now I cannot see myself putting any more money into this car.

If it is a lifter, it is actually fairly inexpensive to fix. Your labor is free. If the engine is damaged from a bad iMS, then that is $10K or more.

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I'm guessing your engine never had the updated Vario-cam wear pads updated to the improved parts. Excessive wear allows the camshaft chain to get off track & then the timing is off. Here is a pic of worn pads:

Timing is presumed fine, engine ran great minus the ticking sound. Modern engines shouldn't need anything "updated" or "upgraded" to last 150,000 miles. Porsche put a piece of crap engine in a great chassis. No excuse for it other than greed. All of my old air cooled 911's have/had way over 100,000 miles and never a blip. I can't see myself needing to learn this lesson twice …

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Well, your ownership of a 996 is fairly new and you have not seen all the issues yet. The timing chain ramps is well known for wearing out. I replaced two that look like the picture at 78K miles. You cannot make the statement that timing is presumed fine unless you hook up a Durametric and find out what the timing values are while the engine is running. Guessing, and opining about cam timing is … really not valid.

when you check the belt tensioner /idler, check the play on the water pump pulley / shaft. could be that the water pump is going.

Maybe try the stethoscope trick and try to isolate the noise?

Everything was checked 3,000 miles ago before I purchased the car. I went over it myself and with my mechanic. We fixed a lot of minor things. There is no excuse for this. Modern water cooled engines should last 150,000 miles. I'm going to drag it over to the shop and see what has failed before throwing a molotov cocktail through the window and dropping it from a helicopter on the front lawn of the local Porsche dealer.

How long do these motors go in general?

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Until the weak links broke. On the 996, the weak links are: 1. IMS bearing 2. Chain tensioner pads 3. Chain variator 4. Valve lifters You WILL have one of those before 100k miles

Well this has been a very interesting journey to say the least! My foray into the water cooled Porsches has been a real eye opener. I've been involved in repairs of these cars enough to see the dark side; an IMS bearing failure (5% of cars suffer this), chain ramp failure that chewed up one bank and jumped time, bad lifter that just made noise occasionally, multiple transmission failures, and a bad water pump. These were all 996 from 1998 to 2002 I believe. A smattering of what is out there and nothing to really form much of a judgment based on the number of failures the shop was seeing versus the number of 996's on the road. My comfort was knowing the failure percentages might be small and that we had a competent mechanic that could fix these things. Well this one sure tricked me, but it didn't trick all of you. One fella hit the nail on the head. RRico stand up and take a bow. The problem was the water pump . I have never in my life heard a water pump make a noise like that. How we found it was when I was preparing the car for transport I saw a quarter sized spot of antifreeze on the floor. I looked up under the car and saw it was dripping out of the water pump seep hole. I called my mechanic and told him what I found so that was the first thing checked. Started the car and the metallic ticking noise raised it's head. Removed the drive belt for the water pump then restarted the car. Ticking noise gone. Replaced the water pump and drove her home, all normal again. The car gets a reprieve, for now. I love this car but I'm sticking to my guns, Porsche made a great chassis but they really blacked the eye of the enthusiast with this engine. The Yelcab1 list is pretty sobering. Well back to enjoying the ticking time bomb, ha!

Video did seem to point to an external accessory type noise. The water pump was hopefully replaced with the new upgraded part, part number starts with 997. Another noise that gets people worked up is loose spark plugs. The pressure sneaks past and makes a chirpy noise.

Congrats. I think that many of these cars are quite dependable, the majority in fact it seems. This in spite of the fact that they are often owned by folks not really enthusiast oriented as it were.

Thank you! Yes the fellow I bought this car from wasn't really an enthusiast, it was his daily driver. I've driven the car a bit sense bringing 'er back home, reprogramed the stereo after the battery disconnect and all is right with the world again. I really like this car but really don't like the looming feeling of "what next?". I'm keeping the helicopter rental open ended for now. The Yelcab1 list of fatal flaws can all be preempted, but doing so with the lifters would be pretty expensive. So what is the deal with the lifters? Why exactly do these particular lifters fail and what is the best fix? I've looked on line of course but would like to hear the opinion of 996 people on the paying end of these problems.

We maintain quite a few 996s and I must say the lifters haven’t been problematic. I have done a couple on 993s. I’d say going too long between oil changes could cause problems...

What did the water pump repair cost you?

With that much play to create loud ticking what shape was the pump in? Was the bearing play bad enough that the blades contacted the block?

Not sure exactly what broke on the water pump but when you spin it the thing rattles. I need to take a closer look. No block damage, whatever broke did it suddenly. We repaired a bad pump on another 996 in the shop a few months back and there were scars on the block from that failure. The new pump was $360 from Porsche which seems like a really ludicrous price to pay for a water pump that didn't last any longer than the one in my Chevy. Very ironic that the first item to break on my first water cooled 911 was the water pump. My '87 Carrera is still laughing at me.

I have been driving, owning, and servicing (more than just my cars) 996 and 997 for a while now. My standard recommendation is to change all the idle pulleys, water pump, and thermostat at 60,000 miles. The water pump is a maintenance item, not a wait til it breaks item. You got 92K miles out of your water pump, I would not complain, really. Sure your 87 Carrera is laughing at you but that also has its own maintenance schedule starting with valve adjustment every 15K miles which the 996 does not have. And we all know about the Dilavar head studs of the air cooled Carreras.

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There was a discussion a while back comparing the failure outcome of water pump blades.A metal blade scores the block while a composite blade shatters and scatters through out the coolant passages. Jake Raby pointed out that even low mile cars are affected because the composite blades brittle with age. Perhaps my old 87 Carrera laughed at me too. It's gas tank vacuum crumpled on me. The fuses kept vibrating loose. Sweating, freezing or smelling the climate controls sucked. The shifter throw distance from 1st to 2nd must have been two feet. The heavy clutch made my left leg bigger I'll let it have the last laugh. Even though it was "retro" there's no going back from my C4S.

I noted that Excellence magazine recommended replacing water pumps with the genuine composite plastic one every 4 years or 40,000 miles whichever came first. They also stated to drain, flush, and refill coolant with 50/50 Porsche coolant/distilled water every 2 years.

Yes, that Excellence mileage recommendation was from Tony Callas I think. Easy to replace once you’ve done it once.

Well I don't expect as much out of a 31 year old Carrera as I do a 17 year old 996 with less than 100K on the clock. Everything works on my '87 Carrera. Valve adjustments are a crude throwback that should have been eliminated by '87 but other than that it shifts perfect, drives perfect, never had to change the water pump ... and speaking of which; 40,000 mile recommended change interval? Really? What year is this 1968? My 2002 GMC Sonoma has 155,000 miles on it and still has the original water pump, alternator, and clutch . Yes it has the original clutch. And thankfully it remains reliable as it has been needed as a parts runner for the 996 many times. I love driving the 996, love the style, love the handling, love the modern feel. Would love it more if the engine wasn't a ticking time bomb and an LS swap didn't cost $20K bucks. 'course then I wouldn't have been able to buy this car for 1/10 what it cost new. So quit your whinin' and enjoy it while it lasts.