The question no-one wants to ask. Ever.

[RarlyL8]

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?

[yelcab1]

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.

[RarlyL8]

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?

[RarlyL8]

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 ...

[FPB111]

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.

[RarlyL8]

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.

[BYprodriver]

Originally Posted by FPB111

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.

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.

[Linderpat]

Originally Posted by RarlyL8

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.

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.

[RarlyL8]

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.

[Linderpat]

Originally Posted by RarlyL8

...Yes the car is beautiful inside and out. I absolutely love it but if they are this delicate I'm done.

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.

[RarlyL8]

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.

[yelcab1]

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.

[BYprodriver]

Originally Posted by RarlyL8

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.

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:

[RarlyL8]

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 …

[yelcab1]

Originally Posted by RarlyL8

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 …

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.

[RRico]

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

[sugarwood]

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

[RarlyL8]

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.

[rbogh901]

How long do these motors go in general?

[yelcab1]

Originally Posted by rbogh901

How long do these motors go in general?

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