Miller_arch

Good question...6 times as follows:

2,315 Miles July 18, 2002
3,711 Miles May 23, 2003
5,829 Miles July 19, 2004
6,900 Miles Oct 29, 2004 – also replaced cylinder head cup seal
7,781 Miles Aug 24, 2005
9,991 Miles Aug 17, 2007

I bought the car with 10,500 miles on Jan 24, 2008 with a 2 year CPO Warranty.

ls911

That's excellent!!

Hope the sound goes away on your next oil change

chily2008

I was just playing with the car. I drove about 20 miles on an empty highway. I was about 75mph. When I got to my home and parked in my garage, I checked to see if the tapping sound was there. It was and it was quite loud. I let the car sit for about 1 hour, went out to my garage and started the car. The tapping was there but it wasn't very loud. I left it idling and walked out to my mailbox, when I came back the tapping was gone. I have not been able to tell exactly when the tapping (clicking) noise comes on but it seems to be worst after highway driving. Often it is present when idling but then goes away after a few minute. Does this sound like a stuck lifter? It seems to me that a stuck lifter would be better after highway driving?

chily2008

Last night I was at my local auto store. I saw a product by Gunk called Valve Medic. It is meant to get rid of engine gunk and help stuck lifters. I was certain that it was snake oil and that it would be a waste of 5 dollars just like most of the other additives. I figured that it would most likely not do anything to my engine- good or bad. I purchased a bottle, added per the directions. They said that it would unstuck a stuck valve lifter within a few minutes- guess what!!! It didn't do anything!!! That was last night. This morning I started the car, no tapping. I figured that it was just a coincidence and didn't have anything to do with the Gunk additive. A few times during the day, I went out and started the car, no tapping. This was strange because it normally would occur during similar situations. I then decided to do a highway drive for about 20 minutes- this always causes the tapping when I stop and idle. I completed the drive and no tapping. I have tried a few other things that would normally bring out the tapping and I was not able to make it tap.

It hasn't been 24 hours yet. I am going to change my oil in just a little bit. I haven't had a day without tapping for several months. I do think that this stuff helped the problem however I really doubt that it will last long. I will keep everyone posted.

jury_ca

^^Yes, please do change your oil and tell us if it comes back. The GUNK product might have changed the viscosity/friction modifier properties in the oil in some way. You might lose these "benefits" if you change your oil once again. I don't think Porsche recommends using oil additives, and I'd stay away from them.

Robin 993DX

Typically the GUNK, Marvel Mystery oil type of engine cleaning product is just transmission fluid which have great detergent effect to loosen up any sludge build up. When you pour the GUNK into your oil filler tube did you notice the color being slightly red?

chily2008

Yes, it was a very dark red. Very thin consistency.

chily2008

Three days from adding GUNK Valve Medic- still no tapping. I changed the oil last night with Mobil 1 0w-40. I have checked two times today and no clicking. I still do not feel that it will last but we will see.

chily2008

24 hours after the oil change- the car is ticking away like normal. I think that the verdict is a someone mentioned- the GUNK valve medic simply changed the viscosity of the my oil. During the time that I the GUNK in the car (before the oil change), I noticed that the small drop of oil on my garage floor every morning turned from one small drop to a small puddle the size of a half dollar. I think that the small puddle conforms the viscosity therory.

Steve

redridge

what oil did you use? I had a slight tapping noise... and when I used 15w-40 the noise went away.

1999Porsche911

So? Are you going to change to an oil that better protects your engine from the metal to metal tapping?

chily2008

I used Mobil 1 0w-40.

chily2008

I have been reading too much and now I am confused. What weight would better protect from metal to metal tapping?

Long story why but I have a huge amount of various weights of Mobil 1 at home. If there is a better weight that would protect, let me know. I realize that I am opening a huge can of worms here.

Benjamin Choi

you're getting to the point of sounding desperate dude. don't give out bad advice with your 15w.... oh now 5w BS.

Macster

and disassembled it (took pictures may be able to provide link). The device relies upon very close sliding fits to retain oil and oil pressure and a check ball valve. If the ball or seat of this valve fails to seal due to a bit of dirt in the oil that got pinched in this ball/seat interface...But enough wear to cause a lifter to fail to maintain pressure, especially at higher engine speeds when the pump is putting out a big volume of high pressure oil.

What can happen is for some reason (well, either related to sub-par lubrication or material defects) a valve lifter face or camshaft lobe or both can wear.

In this case even though the lifter is fully pressurized and maintains this at all times, under all operating conditions, the gap due to wear is too great and the tapping/ticking is what you hear.

In this case, the noise will be present at almost all engine speeds though could be more pronounced a higher engine speeds. There can be variations in the amount of noise, the characteristics of the noise at different engine speeds, too.

Another possibility for the noise is for some reason oil pressure or oil delivery is restricted to one or more lifters. A blockage is very unlikely. What I've found in at least one engine -- not a Porsche engine -- is very worn camshaft bearings allowed what was essentially a huge internal oil leak and oil volume and pressure to the lifter gallery was reduced. They were noisy because they lacked oil and oil pressure.

An oil pressure check can determine up to a point the engine's oil pressure is up to par and of course you want to check the oil pressure as close to where it enters the head and the lifter oil passages.

Do not however, focus solely on lifter noise. A ticking/tapping noise can be a noisy fuel injector, an exhaust pipe leak (at where the exhaust manifold bolts to the engine head or a crack weld), or a loose spark plug or a bad spark plug connection or a damaged/cracked spark plug. (A spark jumping from the spark plug lead to ground can sound very much like a tick/tap.)

A good mechanic can work to pinpoint the area of the noise and if a Porsche shop with the right equipment can command the engine controller to shut off fueling/spark to each cylinder in turn and by this eliminate some sources of the noise. A cylinder that is disabled and results in the least amount of RPM drop at idle is the weak cylinder. In this case the noise could be from something more deeper in the engine, like a burnt valve or a broken ring.

You can try oil treatments but you want to be sure you do not attempt to 'fix' an tapping noise with some substandard oil additive when the noise is in fact coming from another source that is not oil related.

One doesn't want in trying to shotgun diagnose the source of the problem to make the situation worse or do even more harm to the engine.

Say it is a flat cam lobe. No big deal really. Pull the camshaft cover the camshaft and replace it. Renew/replace any lifters that are worn and button engine up and it will be as good as new.

Sincerely,

Macster.