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Old 06-26-2012, 05:26 AM   #1
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Sporadic tapping noise until war.

I have a 2000 2.7 986 with 55,000 miles (90,000 km.) and have noticed a sporadic tapping noise from the engine until it is fully warmed up. It does not 'rattle' on start-up and I can detect it from inside the car only when beside a wall that reflects the sound, as it is not very loud. If the car had mechanical lifters, I would suggest that it sounds very much like the tapping/clicking noise that was common with the earlier air cooled Porsches/VW's that were equipped with the same. It seems to disappear once the engine is warmed up.

I am assuming the problem is related to the chain tensioners; alternatively, I wondered whether one of the hydraulic lifters could be sticky? Either way, is this something which I need to address immediately? I have had the car for 3 months and have put 3000 trouble-free km. on the car and the situation does not seem to have worsened.

Thanks

Brad


Last edited by southernstar; 06-26-2012 at 05:40 AM.
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Old 06-26-2012, 06:32 AM   #2
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PS I love the car. I haven't had a Porsche for 20 years (my last was a 944) and the appearance, handling, braking, sound, acceleration and overall balance are just outstanding. The ony thing I hate is the 'ticking time bomb' feeling that I just can't sem to overcome (and no, I am not referring specifically to the noise which gave rise to this thread). I have never owned a car where I have spent so much time listening for noises or other signs of impending doom! It is shocking that Porsche engineered a car with so many flaws and were seemingly unable or unwilling to address them over the passage of time. I refer, of course, to the IMS bearing, but also various other components that have a life-expectancy that is far below what one would expect in a modern automobile: the air/oil separator, coolant expansion tank, various seals, control arm bushings, water pump, etc.

Of course the up side for those of us who purchased our cars used, is that the depreciation on Porsches (and the 986 in particular) has become huge becuse of these flaws. People who are not in the market for one generally expect that the price that we paid for a used one would be MUCH greater. So yes, the car has some serious issues and the cost associated with ownership is very high (like many others, I have decided to spend about $3000.00 to replace the clutch/IMS bearing as a preventative measure this winter). However, at least the ridiculously low prices for which immaculate, low mileage 986's can now be purchased allows buyers to go in with their eyes open and to budget a substantial amount for improvements/repairs. Even allowing for about $5000.00 to replace an IMS bearing, clutch, waterpump, air/oil separator and coolant expansion tank, one is left with an incredible car for a price under $20K!

I must say, however, that had I purchased my Boxster new in 2000 for about $60,000.00, maintained it meticulously and driven it only 55,000 miles in 12 years, leaving it in virtually mint condition, I would have been rather disappointed in the resale value. By neglecting to provide extended coverage on cars where the engines have self-destructed due to a design flaw (except for some original owners in the first 10 years), Porsche apparently believes that they were at least protecting the original owners; the reality is that even if those owners did not suffer from a failed IMS bearing, they have still suffered the most for this design flaw as it resulted in these incredibly low resale values.

Anyway, I came into this with my eyes (and wallet) open and don't regret the decision one bit. I, as a result of these design flaws, paid a ridiculously low price for what is, in terms of sheer visceral enjoyment, an incredible car.

Brad

Last edited by southernstar; 06-26-2012 at 10:24 AM. Reason: sp
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Old 06-26-2012, 11:59 AM   #3
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Even though the tag line for the thread suggests something to do with a war being the way to end a tapping sound (sadly, the 'm' in warm was one too many digits), I'm still a little surprised that no one else has experienced this noise, or responded. Or, for the reasons alluded to in my second post, am I getting a little too paranoid about noises from my car? Of course, after posting this, I took the car out twice and it failed to make the noise on either occasion (mind you, the engine was likely still a little warm).

Brad

Last edited by southernstar; 06-26-2012 at 12:02 PM. Reason: 2 signatures
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Old 06-26-2012, 12:26 PM   #4
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I'm still a newby to Porsche cars, but it sounds (no pun intended) like you have a lifter that is not pressurizing immediately (they're hydraulic). While not catastrophic, it is something that I would fix. A stethoscope will quickly help you identify the troubled cylinder.
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Old 06-26-2012, 01:56 PM   #5
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It does sound like you have a lifter noise which is common as they are easily clogged. I would make sure you have enough oil, drive until engine fully warms up, drive at 4,000 rpm for about 10 miles, & change the oil & filter with 5W-40 oil.
Search the forum for oil brand advice.
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Old 06-27-2012, 03:34 AM   #6
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Thanks for both responses. The oil and filter were changed ( Mobil 1 ) as part of my PPI only 2500 km ago, so should be fine. Of course, I haven't had a repeat of the sound since I put up my post, but a sticky valve lifter was one of my suspicions but didn't know if others have had the problem. I will try to give her a good steady run at moderately hight RPM's tonite.

Brad
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Old 06-27-2012, 05:24 AM   #7
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Is the noise occurring when you first start it, to say a minute or two? If so, that is normal for it to sound a little more "knocky" since the engine is dumping fuel in there until about 2 minutes after startup. The idle drops and then she should sound fine. Is the knock, knock happening AFTER that?
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Old 06-27-2012, 05:46 AM   #8
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Quote:
Originally Posted by southernstar View Post
so should be fine
famous last words. take a few moments to check the oil level (when the car's cool and on level ground) with the dipstick. maybe it was under filled...

lots of threads on here about noise + mobil 1. try switching to a better oil (if you're so inclined) and see if that makes a difference.
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Old 06-27-2012, 07:19 AM   #9
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I had the same thing and was equally concerned only because I had not hear or paid attention to the noise before. Took it to my local mechanic and it was indeed a lifter noise and was told it was nothing to be concerned about. That was a couple thousand miles ago. I hear it every once in a while now but have had no problems. Car is in having the oil changed today so will see if I hear it after fresh oil.
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Old 06-27-2012, 11:21 AM   #10
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Originally Posted by Homeboy981 View Post
Is the noise occurring when you first start it, to say a minute or two? If so, that is normal for it to sound a little more "knocky" since the engine is dumping fuel in there until about 2 minutes after startup. The idle drops and then she should sound fine. Is the knock, knock happening AFTER that?
"Dumping fuel" should not cause a "knock". It may cause a higher idle, but the lifters should be fully pressurized in seconds, not minutes. Start up valve train noise should should be brief...very brief; anything else indicates an issue.
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Old 06-28-2012, 05:00 AM   #11
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Yes, of course I have checked the oil level after the change (and do so with each fill up) and it is perfect. As I indicated, the problem occurs after start-up, but only sporadically. Last night, after reading these posts, I started it up in my garage and heard the noise again; when I revved the engine at first it was a tad sputtery, as if flooded; I revved it a few more times and the sputter cleared and then so did the knocking sound. So yes, it seems that in fact it is a 'knock' rather than lifter noise. The problem with my earlier description was that I could ony hear it, as I mentioned, when there was a wall beside the car to reflect the sound and, obviously, once I drove off I could not detect it any longer. I did notice that after it was warm - i.e., when I went to park it, it no longer made the noise.

I simply (and stupidly) did not connect the roughness on start-up with the sound that I was hearing. Having said that, often on start-up there is no initial roughness (or sound) - i.e., as indicated, the problem is sporadic. Is there something I should (or shouldn't) be doing before parking the car that could eliminate this?

Brad

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