1999 Porsche 911 Carrera - engine tick and 2K rpm's at cold start

1999 Porsche 911 Carrera - engine tick and 2K rpm's at cold start. otherwise the car runs excellently. any ideas? stuck lifter? how do you fix a stuck lifter? thanks 013 - YouTube

Thats not a lifter. Its not at the right rhythm and it has oscillation. When did this start, and has it progressed? Does this happen cold and hot? Does it go away when driving?

Water pump, cat, or idle pulleys? Could also be a loose spark plug. Should be easy to diagnose with a mechanics stethoscope. May also want to remove the serpentine belt and hand spin all the pulleys and accesories, then start engine briefly to check for noise.

Does it go away after a few minutes? If so, likely a chain tensioner.

#1 - very difficult to hear much of anything with that sound file, but I digress... #2 - I don't hear a "tick" per se' - at least not a valve/lifter tick like I've ever heard before. #3 - I do hear what sounds more like a "knock" or a diesel motor sound, but it's at a very low level and buried beneath all the other engine noise(s) (belt, idlers, sai, etc. ?)... i.e. lot's of variables I'm interested to hear the diagnosis/outcome of this - please do post when you find out more! Good luck

The RPM's are apparently typical having seen a post or two in the last few years. Mine does it. Also when really cold there's often a second gear crunch the first time it goes into second. Thought I was ready for a look at the transmission but there was a flood of posters that said that was normal. There's a thread on it somewhere.

thanks for all the comments - this happens only at cold start and lasts for about 10 seconds - I've had this issue since I got the car in October. I guess it is more of a knock than a tick.

I think this is very common. I hear about the cold start tick a lot with the 996.

Chris, I thought Jake was going to chime in but in his absence, I'll try to give very amateurish to help you focus on likely/unlikely issues. Have you replaced any parts recently ? Have you examined the oil filter pleats or sump plate? Chain tensioners tired ? Durametric numbers are erratic ? Are you using peculiar oil ? Use a stethoscope to pinpoint where the noise is loudest. Low oil pressure warning ? Exhaust manifold leak ?

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Can we place bets? I'll put down $20 that its the tensioner. This is common and not significant at the point you are at, IMHO.

The brief jump to 2K after engine start is normal. The noise? Put me down for a water pump or possibly something else with the accessory drive system, like an idler roller bearing or tensioner roller bearing. Since the noise is present at cold start you can remove the serpentine belt -- carefully note how it is routed and its direction of travel so you can replace it exactly as it was before -- and start the engine. If the noise is gone then replace the belt and start the engine again and confirm the noise is back. If the noise is still present with the belt removed then possibly the noise is internal and you should have a professional tech make the diagnosis. BTW, if the noise is absent with the belt removed check all accessory drives for any drive with bearing play. Go around several times to get a feel for what no play feels like vs. play. My experience with a bad water pump was while it had play it was not very much. It was only because the other drives had less (essentially no play) that I settled on the water pump and had it replaced. My diagnosis proved to be the right one. Also, check the belt for sharp edges. If you find one or both sharp this is a sign the belt is rubbing and it is rubbing because it is not tracking properly and it is not tracking properly because of an accessory drive with bearing play which allows the pulley to move out of position. Last but not least, the noise while maybe not from the accessory drive, doesn't have to be from inside the engine either. My 2002 Boxster had a similar noise at cold start and the cause was a loose converter brick. Warm it didn't knock. The exhaust buzzed quite a bit though when everything was warmed up and I suspected (at least hoped) it was a loose heat shield but when I had the tech look into this he confirmed my fear and diagnosed the converter was the source of the noise. This proved to be the case for I replaced the OE converters with a pair sourced from a salvage yard and the knocking/buzzing was gone.

While you are in there -a simple pulley alignment check. Place a straight-edge across the face of any pulley - so the straight-edge touches both edges of the chosen pulley.Adjust the straight-edge so it crosses over the faces of an adjacent pulley. You may be surprised to find a misalignment. Mine had this issue and it had caused the serpentine belt to fray on one edge.

sound is coming from the left side of the engine; I just had the water pump replaced; would the sound be coming from the water pump due to bad install or due to whatever the water pump is connect to? Maybe the water pump broke for an undiagnosed problem I still have? I don't have experience with tensioners, the belts I can see are in good shape. no oil pressure problem, using W0-40, or W05-40, whatever Porsche recommends. had the car checked by Porsche dealer when I got the car in Oct. Started at ticking at cold start and seems to have gotten a little louder and now lasts a little longer. thanks.

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A water pump can fail at any time. Do I think it a water pump? Not really. (I hope I'm wrong and it is a water pump unless it can be something even less serious and there are less serious explanations.) You need to get the car flat bedded to a qualified/experienced Porsche tech and fill him in and let him make a diagnosis. At this stage the less the engine is run the better and really it should only be run under the supervision of the tech. However, to ease your concerns some that the noise has been present since October and the engine is I take it still running and running ok suggests (?) the noise is not a sign of pending doom. But I prefer to be conservative and that is why I advise you to get the car to a tech and let him make the diagnosis. He'll probably drop the oil filter housing and check the oil and the filter element for anything scary. He can check the water pump and other accessory drives. If he finds nothing in the oil filter housing oil and filter element and the accessory drives prove to be ok and the plugs are not loose the exhaust is not leaking and so on, then he can start the engine and give a listen with a stethoscope and pinpoint the source of the noise. From this then he can offer his professional opinion as to what it means.

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Was this ever diagnosed? I would love to know what the problem ended up being.

+1 for a pulley making that noise.

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That is what I thought. I am a newer 911 owner and have not yet worked on my own car, so how much would a repair like this run on average and would it be hard to do in my garage?

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Drive pulleys on the 996 are a relatively easy DIY project. The OEM part is under $150.00, but if you had Porsche do it, I would imagine it would be well over $1000. Just my 2 cents worth. We call it "Porsche Tax".

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I learned about the Porsche tax when I asked the dealer near me for a quote on changing out the IMS and they said $5,000! I simply did my research and decided to leave it based on my build date. But, before I try to diagnose this, would a pulley really result in the noise in the video posted by OP? That is exactly the noise my car makes, although mine isn't quite as loud.

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Are you experiencing this type of noise too? If so, why not post a video with the camera mic near the belly of the engine... close to the oil filter and then move to the other side, and then end at the top of the motor. I would rather have the more experienced Rennlist members comment on this. When I listened to the video, I thought it was a lifter, but I'm no mechanic and Jake Raby is the "M96 Whisperer" and if anyone knew what that sound actually was, it would be him.

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I am. The car had a recent PPI and they went through it with a borescope and the cylinders were fine. The noise actually comes and goes with the temperature. On very cold days it would be very apparent, but on a day where it was milder it would be very faint or non-existent. It happens the first start of the day and goes away after as little as 10 seconds. Maybe it was because I wasn't driving it every single day, but I cannot be certain. Once I start the car again I will make sure to record it. It doesn't seem to me that it is coming from the cylinders. I am in Canada, so I have no intention on starting the car until it is warm again. Not sure if this helps, but the car has a new coils, plugs and seals around the spark plugs. Other than that, the oil has always been changed every 3000 miles and the last change had nothing in the oil. I had a very thorough PPI completed on this car. Hopefully someone knowledgeable can chime in because I do not think the OP is still around.

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What did the PPI guy have to say about the noise? Noises are hard to diagnose. Unless one is wiling and able to do the actual final diagnosis and have confidence his diagnosis is correct I recommend gettng a professional Porsche tech involved. You can read my (and other) previous posts for my thoughts on what the OP's engine noise was possibly caused by. If your engine is making similar sounds then what I said then applies. Let me continue which may be a repeat of what I posted to the OP... You really have to determine if the noise is coming from the accessory drive or some an exhaust leak or a loose plug or something in or under the car touching something it should not touch, and so on. If the noise is present from a dead cold start you can after carefully noting -- take pics or draw a diagram -- of the belt's routing and its direction of rotation remove the serpentine belt and start and run the cold engine a few moments, long enough to ensure the noise is either still present or not present. Assuming it is not present then shut off the engine and reinstall the belt and confirm the noise is present with the belt connected. Actually though what I would do, have done, is before installing the belt give all the accessory drive pulleys a good test for any play. The pulley per se won't be the source of the play (assuming the pulley is not loose on the shaft which while possible is very rare) but the pulley/shaft assembly (which in this context are treated as one) will have the play which comes from bearing wear. In the case of my Boxster and its noisy water pump the play was not huge but there was some at the water pump while there was no play at any of the other accessory drive pulleys. All the idler/tensioner rollers appeared to be in good shape so my diagnosis was the water pump and I had the car flat bedded to a dealer -- around 25 miles away at the time -- and had teh water pump/T-stat replaced. Noise gone. Along with testing for play check the belt edges. If there is bearing play the belt will not track well and it can rub against a pulley side. These belts are not the kind to make contact with the sides of the pulley (they are not "v-belts) so if one is making contact this can be obvious from a sharp edge. In the case of my Boxster the inner edge was sharp, the outer edge was dull. And it was dull like the edges on the old belt which I had still around. If the noise is present with the belt removed then you have to install the belt and look elsewhere, listen elsewhere for the source of the noise. It would still be out side the engine, from a leaking/cracked exhaust, loose exhaust system, possibly a loose heat shield, or something loose. (Some years back I found some of the IIRC 14 fasteners that hold the stiffner panel (a thin sheet of stamped metal) to the diagonals under the rear of my Boxster missing. Don't know why they came loose. I never had them off but they were removed once long time ago when I had the car in for an RMS repair. I replaced the missing fasteners and torqued them down and they have remained present and tight ever since.) Just one more before I have to leave for work. Off and on I have noticed a dull irregular and faint "knock" from my Boxster at cold start. The noise is not loud and it is not in sync with engine RPMs, in that it doesn't sound like a noisy lifter. The knock goes away in just a few moments. (It is not the "loose brick" knock that I used to hear from a bum converter. This went away when I replaced the original exhaust manifolds/converters.) What I think is going on is after I shut off the engine -- after a 30+ mile drive from the office to home the serpentine belt cools off and takes a "set" kind of like the high performance tires do when they cool down overnight. The next time I start the engine the belt with its set causes the tensioner to flay about a bit and this is the knock I hear. The knock starts to go away almost as soon as I hear it and is gone in just a few seconds which kind of fits with my diagnosis that it is belt related. The belt is while not real new not due to be replaced. The idler/tensioner rollers are all original and have over 308K miles on them. They give no sign of needing to be replaced but I wonder if perhaps the tensioner is loosing a bit of tension and this accounts for the noise I hear? Just a thought or two. Got to go to work.

My questions may help the OP. I too have this issue. I was told it was chain slap. Like OP only on cold start for maybe 5 to 10 seconds. Took my belt off and felt for play in the pulleys. My 2 idler roller bearings and tensioner roller bearing have zero play no matter how hard I giggle them. My PS and A/C pulleys have ever so little play. My water pump pulley has a very very very slight wiggle if I use both hands and give it good tugs back and forth. Should there be any play at all in the water pump pulley? And the PS and A/C, should they have any at all? I can't do the start up with belts off cause my oil sump pan is off right now. I'll have to wait until that's back on. Thanks

Perhaps I am being 'slow' but there are 2 noises in the clip. One is normal(?) belt & mechanical noise(low p/s fluid?), the one of concern is a light knock/ticking that is distinctively slow speed . Since it is always(?) present in cold ambient+engine temps and disappears with warmth -that gives an excellent diagnostic opportunity. The next stage would be to pinpoint the source(s) of the noise. We can chatter about this and have fun with speculation . Alternatively someone could use a stethoscope. Leave the car on the rack (or ramps) overnight .Following morning put on Arctic survival gear and get out with the stethoscope. If I were doing this and was impatient/cold I would check the lower portion of each cylinder first.Not the crankshaft bearings, the bottom of the piston stroke. If the tool or your experience is inadequate to distinguish the two, take it to an Indie who does have the right tool/experience. This takes care of the very expensive diagnosis. After that ,systematically listen to each cylinder ,top to bottom.Then do the timing chain area.This would be for the slightly less expensive... Optimistically and since the car had some work done - maybe it is something trivial like loose spark plug? Question for the experts(not me !) - with a stethoscope or any other diagnostic tool, how do you distinguish between piston slap and bore scoring in the early stages?

Sounds a bit like this https://www.youtube.com/watch?v=h8YeHa4oT88

I hear 2 noises as well. the knocking noise is what jumped out at me and well - you don't want my opinion on what it is. it isn't good. bUT I always hope I am wrong.

Thank you all for your responses. I think I will just have the car towed to my indy in March. I may try to get a video before then to show you my exact scenario. As I said before, I do not think it is as bad as the above video, but it is the only video that sounds anything close. I have looked through all the bore scoring threads and watched all the videos and my car does not sound as bad as any of those examples, nor does it have the same scoring sound. Also, I did have it borescoped, but of course it could start anytime. I am assuming if that is the issue it may be early. The car runs great, no smoke or loss of oil. I always watch oil pressure and so on and everything is great. The car started this noise beginning of September and I started driving it in August after my PPI. The one problem I have with trying to listen is that the sound really can subside very fast and will not come back until the next morning, so it could be tedious.

AFASIK, You can't borescope bore-scoring from the spark plug hole. Most of the bore-scoring videos are of an advanced stage of wear, not early. Bore scoring seems more prevalent in cold climates. In the early stages ,it may be possible for the oil film to develop and be retained sufficiently to mask it? If so that is more of a run time issue,maybe not so much oil temperature? Pinch of salt required because I am no expert on this subject. Good Luck in March !

So, say I was able to catch it at an earlier stage IF it was bore scoring. Would make the repair easier and less expensive, or is it the same regardless due to disassembling the engine?

Few of us are experts in that subject. Some will just repeat anecdotes from Forums. It is such an expensive repair(if it really is the fault - let's hope not) that I'd suggest read what real experts write - like Hartech or Flat 6. But I commend you for getting the cost/time budget planned ahead of any diagnosis. I got it the wrong way round and paid dearly for my mistake.

My car does this a bit too, most noticeable after it hasn't been run in a while. I'm not currently in a situation where I can have it thoroughly inspected, so I am going to keep driving it. Wish me luck!

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Will be the same if you were to go with nickies. Much cheaper if you were to rebuild everything and leave the cylinders alone. But I would measure the cylinders for taper and make sure you CAN leave them alone (if no scoring is present) Remove the sump plate, and use a scope to check out the cylinders through the bottom.

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Woody, Let's pull a "thelma and louise" (in a non-gay way) and go out in the blaze of glory!!!

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Deal!

We had a noise similar to this on our 986. It ended up being the rusted old exhaust heat shielding. Best luck to your diagnosis and a speedy recovery

Here is hoping it is something loose like that. I would be pretty upset if it was cylinder related due to the fact that I went all out on a very pricey PPI because I was nervous of scoring. Thank you for the response!

Just check your PPI Invoice. Unless it specifically states sump plate removed & a borescope was used - you/they have no diagnosis of bore scoring. Removing the sump plate is rather intrusive but is one of the most instructive procedures on an old M96 engine. Amazing what you find there sometimes ! And by the way, taper is only part of the story. There is ovality also. Can't really measure either with the engine assembled in the car. These 2 issues are may be what others call 'piston slap'. The outcome is either replacement ,good-used crankcase halves or Nickies. You really need to find an M96 expert locally. All this keyboard speculation without even stethoscope results is just chatter.

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I dated a girl in high school who would get pissed and slap.

With that level of wit, I'm not surprised !

Ha! "Pissed and slap"! Wow.