Spyerx

Hi, my 2009 997.2 c2 23k miles had sat about 2 weeks as I was out of town. It's been cold in SoCal and was about 40 out yesterday morning. I started car, started right up and heard a not normal cold start tapping coming from left side of engine. No smoke, oil level full, oil pressure normal, no codes or lights. Noise would vary with engine speed. Went away after a few mins and engine was warmed up. Car drove totally normal, power good, and sounded completely normal with several restarts.

Car sat overnight. Cold again. Started this morning. No noise, normal cold start.

Questions- any idea what this might have been? Should I be concerned? It's going to sit for a few days and will give it a try later in the week.

mattyf

My guess would be a stuck lifter.

I've heard of it happening on the .1 cars. Don't see why it can't happen to a .2 as well. It unsticks as the oil pressure gets to the lifters and/or things heat up in the engine.

If you're under warranty I'd mention it to the dealer. If not then there's not much you can do aside from an oil change. If it keeps happening obviously you have a problem. If it doesn't happen again then I wouldn't worry about it.

Macster

First guess would be one of the lifters under pressure bled down and picked up a bit of air which took time to work its way out of the lifter body.

Nothing to really worry about unless the symptom appears again and again and again or the noise appears when the engine is hot or there is untoward behavior from the engine.

How fresh is the oil? Oil with miles/time can get contaminated with unburned fuel and water and this makes the oil thinner and can make this bleed down (possibly) more likely to happen.

Spyerx

Oil was changed in nov and has about 1000 miles on it. Done at local pcar dealer with mobil 1 0w-40. Been traveling a lot past few months

This was my thought, also. I out of town for a few days and will drive it later this week. Will mention it next time I'm in for service, before my warranty runs out in July. Have CPO too.... So I'm not too concerned.

Papa Fittig

In my experience this type of sound, if its completely gone after a warm up is very likely to be from a chain due to a hydraulic chain tensioner being dried out.
Here is an article from Flat6innovations:

"Have you ever fired up your M96/ M97 powered Porsche and heard an odd mechanical sound immediately upon start up? Lots of myths exist about what this may be.. What you are hearing are your timing chains screaming! This is not good for the engine and here is why:

The timing chain tensioners are hydraulic, so they adjust with oil pressure variations. When the engine sits for a few hours or days the tensioners lose their "prime" and this allows the timing chains to become very loose. When the engine starts, prior to receiving enough oil pressure to "pump up" the tensioners the tensioners are a bit lazy and this allows the noise of the timing chains to be heard in the cockpit,

The timing chain tensioners are at the end of the oil system and are notorious for becoming dirty and having their passages plugged with debris. Dirty and worn tensioners make even more noise at start up.

To quieten the engine and sep the accelerated timing chain wear associated with this, simply remove and clean the tensioners, or replace them with new like items. Also choose an oil with an elevated level of moly content. If the problem persists you may have timing chain wear that may require intervention from an M96/M97 engine specialist."

http://archive.constantcontact.com/f...102070863.html

Macster

My info is the oil pressure sensor is at the end of the oil system not the chain tensioners. The oil pressure sensor is located about as far away from the pump as possible.

What a loose timing chain sounds like is like a chain (regular old link chain) being dragged across a log or heavy piece of lumber.

The noise lasts just a second or two with of course the longer duration coming upon a cold start after the engine has been off a while. If the car has been parked overnight I barely hear it. Let my Boxster sit a weak and I hear the chain over a log noise big time.

Macster

Just a general comment. Do more than mention it. While I do not think there is anything wrong with your car's engine that more frequent use wouldn't cure be sure your concern and report of the details of the incident is written down on some kind of invoice and what you were told to do or not do about this.

Just in case you want a paper trail that you brought this to the attention of the dealer before the warranty expired.

The oil is fresh so that possible cause is out of the picture.

I think you just let the engine sit too long without driving the car and a lifter bled down and got a bit of air upon engine start and this took a few minutes to work its way out of the lifter.

Yet anothercrisis

My 2012 997.2S made a clicking noise on start up, which I assumed was lifter noise, one time shortly after purchase (with probably less than 1000 miles) when it had sat for a while without being run. Now almost two years later, after sitting for longer periods I do not hear the noise.
Good Luck!

bdiamond001

started my car up this weekend after a 2 week lay off. It sounded as if it was miss firing on one cylynder.
The engine ligt came on with the visit the workshop message. I shut it down and restarted 5 minutes later. Problem solved. Was that a stuck lifter. Car ran perfectly all day.

Spyerx

Follow-up. Car sat for 4 days, cold out. Started it up, sounded perfect, no noise. Drove car 50 miles yesterday, feels fine.

I will get it checked out soon. I have a few minor warranty items to have done before the 4 year runs out... its on my list of items to inspect with the dealer.