Macster

Almost certainly not a chain broken or engine would not run.

Could be a failed chain tensioner or guide though.

As I mentioned in earlier post I watched tech start engine of Boxster, raise car on lift. Engine idling and tranny in neutral.

Then this tech and shop foreman tech both under car listening. I was standing from out from under car and heard noise. Didn't sound at all healthy either.

Oh, car was facing away from us and we were at the front of a service bay.

I stayed out of the way but even from where I was I could hear the noise and hear it well enough to as I mentioned above note it was not a healthy sounding noise.

It is important to note techs didn't race engine or first drive car around like a maniac but simply started engine and lifted car and then listened.

Oh, shop foreman did bring out mechanic's stethescope to listen to engine at various places to be sure noise coming from where it sounded like it was coming from -- rear of engine (Boxster) where IMS bearing and chain drive from crank reside.

Not sure but I believe the owner of this car received some goodwill. 1st engine replaced under warranty and this second engine while out of warranty had around 40K miles on it and I believe the techs told me the owner took good care of the car.

Sincerely,

Macster.

kst_77

Thanks Macster. The sound disappeared, they removed the oil and no metal ????? They say it could have been nad gas and have asked me to drive it around to see if the sound starts up again.

The tech who had heard the noise says he has never seen anything like this in 30 years. Do I drive it around or should I just get him to open the engine anyway.

Thanks

Barn996

Try to go for a long ride with your tech.

Macster

No. Do *not* have tech open up engine.

If other tech has not heard anything like this in 30 years I found it hard to believe bad gas could be at the bottom of the noise. Your car can't be the only one to get a dose of bad gas in 30 years.

Possible though, I guess. If sound disappeared then if bad gas either the bad gas has been consumed or has mixed in with the other better gas where it can't make trouble.

If tech pulled oil filter housing and poured oil out into clean drain pan and found nothing in the oil then that's a pretty good sign the noise even if mechanical has not yet caused any metal bits to appear.

This does suggest a non-mechanical cause to the noise.

Thus about all you can do is do as the tech suggests.

I would approach this though with caution. Take baby steps, drives, bearing in mind if something serious does come of the noise you want to be in light to no traffic, not too far from home and a flat bed tow truck, you want to be in cell phone coverage.

While driving have a safe place picked out to pull over and shut off engine quickly. Avoid starting engine again. Get on phone and get flat bed truck to come and pick your car up. Stress the engine can't be started, at all.

Also, I would keep rpms down below some upper threshold say 4K, at least for a while. No need to start banging possibly sick engine off its rev limiter.

Pay attention to what conditions were present, what steps you followed just in case noise appears again. If engine cold, warm, or hot. Approx. how long you let engine idle. What accessories you had on: A/C? Lights? etc and so on.

If you start out with car and engine dead cold and drive until everything fully warmed up and no noise, then take a coffee break. 5 minutes later give the engine a hot start and drive around, easy does it, again.

If after all the above and the engine has not reproduced the noise and is otherwise behaving normally, and coolant level good and oil level ok, cause you check these as often as you can under these circumstances, if engine operating normally, then you can push the engine a might harder. Nothing gruesome, but vary the engine load and rpms more.

But chances are if noise has remained away this long it was something relatively minor and transistory, and bad gas certainly gets a place on the list of suspects.

Side note: Buy name brand (top tier) gas, premium, and from a busy station to avoid buying stale gas. Premium gas can go stale rather quickly. Besides a busy station is likely one that offers gas at a lower price than other stations so you're getting fresher gas and paying less for it.

Avoid running gas tank level way down. If low fuel level light comes on that's too low. Increases the odds if water or "bad" gas at bottom of tank fuel pump will pick it up and feed it to engine.

About all you can do.

Best of luck.

Sincerely,

Macster.

Pac996

kst_77 here's a little warning. Strange things the mind will do when worried hehehe. You can build mole holes into mountains. Ignore simple things and think the end of the world is in your face.

I'm not sure what nad gas is the guy you took it to referes to but I imagine it means old gas. Gas has a shelf life believe it or not. If you store or have just bought a car some place has been trying to sell it might have old gas in it. Fuel and or electric can cause misfires. You best thing to do now is get the tank down to half and get some injector cleaner in there before topping off again. Old gas gums up injectors.

If you had all the problems and put some gas in the car before taking it to be looked at it might very well be the fuel was bad. Believe it or not some times you can get bad gas from gas stations. The shop might of heard you say you just bought the car and put some gas in it thats fresh to cure the problem. Guys that store bikes in winter are always thinking some major problem has developed while the vehicles sat while all along its just the fuel went bad. Soring a car you have to use fuel stabilizer to help stay away from the fuel being ate up. I don't think it stop fuel from drying up in the enjectors and passageways to go all gummy but eh.

Take care and I'm glad I'm stopping jabbering on this keyboard.

PS what changes did you do between seeing the problem and the sho getting the car?
Fuel? plugs, filter and such?
Did you just buy the car?
Are you trying to blow smoke till you can post pictures of your car?
Post pictures or the problem will return!

Shark Attack

could this be a failing solinoid on the vario?

Pac996

Below is his original post. I don't know what the codes mean but missfiring is what somebody said. I also think depending on the length of time the engine sat and where could answer some questions. Like if it was at a car dealer and only got started from time to time if at all with out being run up the valve guides could get goofy sticky. I don't know if 77 has had a life time of trouble shooting and cars to repair to know what he is hearing when listening to an engine so all we can really go on is the engine is screwy. That's a great point to start from with hehehe. I always watch out for diagnosing mechaincal when it could be fuel or electrical abnormals. Throwing parts at a problem doesn't work.

SO my cure is to be sold here shortly. It's the new Rennlist diagnostic webcam system. You plug it into the ECU and mount the cameras and microphones according to the supplied diagrams. Please read the attached warnings. Rennlist and its forum members are not to be blamed for remote starting your engine and redlining it to death or remote flashing the ECU to unheard of values. We also offer for a small additional cost a sound proofing barrier to keep your neighbors from going too ballistic while countless members remote start and try diagnosing your problem.

Anyway I guess for now the deal is to get new gas in there, new plugs and air filter with a MAF cleaning that easier than the plugs for sure. Then just cruise it to loosen up the engine if it has been sitting for an extended period of time. One thing I do not like about engines that sit is which valves are open and which cylinders get air in and out that can corrode cylinder walls and other internal parts. I don't think engines sitting works at all. Running an engine will help smooth out problems thats for sure. That's only part of my fear factor of not using a car and letting it sit. I'll just throw gummed bearing and valve guides waiting to be scarred with filth as another. As far as major mechanical problems showing up? I don't think 911's self destruct or break down as much as many think so I like a chew some bubble gum and call it a simple fix approach.

Do not forget injector cleaner in there. You don't want to bake in any gunk in there.

kst_77

The tech changed the oil and filter (no metal). I followed Macster and took it for a drive.....

Cold engine, low rpms for about 30 mins (no noise)
Switched on A/C for 5 mins. The lights for 5 mins. Then both A/C and lights for 5 mins.
Let the car rest for 15 mins and then started her up again and drove a little hard for 15 mins.
Let it idle for 5 mins, let it rest for 10 mins.
Drove back home 15 mins.

The noise did not come back????

I have had this car for a while and been driving it on a daily basis.

Pac996 - I did upload a photograph, will upload some more after I wash and wax the car.

Pac996

Yah baby! You know I do feel the car felt neglected so played sick so it could visit with its brothers and sisters at a prosche shop. Once you take pictures and post them the car should be happy with its new owner and want to cuddle up with you. After washing lift the engine lid to get the water out of there. I watch water drain more than I'd like after washing. Double check in front of the windshield cowl to make sure it is draining the water. Mine played be plugged and was finger primeable to get the tube unplugged. You'll be a happy camper now wooo hooo.

redridge

so the noise went away? What exactly did they do? an oil change and that is it?

kst_77

Yes the noise went away, even before the oil change. Now I am scared to drive for I don't know if I am doing more damage and to what!!!

Will follow your instructions Pac996 :-)

redridge

your only clue is the thrown codes.... all the suggestion on page one should be done at the least... when was the last time you changed the plugs or coil packs?

kst_77

Plugs and coils were changed about a year back 7k miles.

Pac996

I have seen just old oil foul things up. I figure its more drag on the engine and the fumes that cook off and enter into the intake from the crankcase breather don't help the engine run. Could just be the engine was running rough from the O2 sensors needing to be cleaned off by heat and exhaust flowing. Lots of variable with cars that sit around not being used. To be a finely tuned and lubed machine running it has to be done

Macster

Given you tried under several different engine temperature conditions to reproduce the noise and were unsuccessful it is unlikely the noise is coming from a mechanical problem.

With no check engine light, no noise, no other untoward engine symptoms, the noise was almost certainly due to a transistory condition. Bad gas, a plugged injector, even a piece of combustion chamber deposit came loose and interfered with a valve closing 100% for a while.

I read where you had plugs and coils replaced a while back. Generally the last thing touched is the first thing suspected when some symptom appears.

It could be a bad new coil, or a bad new plug, or perhaps a coil that is not attached to a plug tightly or even an improperly tightened plug. You know the shop that did this work and only you can know the confidence level you have in this shop. If the noise returns without a clear indication of its source I'd have the coils/plugs checked just to be sure all is right. If a misfire code or codes appear you can swap coils around and see if the misfire codes follow the coils.

But assuming the noise stays away, and absent any signs of engine distress I think you're ok to drive the car.

My course of action would be to keep my usage of the car local -- no cross country trips for a while -- though varied from city driving to highway driving, and to keep in mind the possibility of the noise returning.

As the miles accumulate and the noise remains absent and the engine continues to behave normally and without any signs of trouble, then your confidence in the car can only return to its pre-noise level and you can begin to treat the car as you did before this episode.

I do much the same thing when I buy a new (or used) car or after I've had a car worked on. I give the car a shakedown period from a drive or two depending upon what was done to the car to sometimes a month or more in the case of a new car or "new" used car until I have confidence in the car and its reliability before I venture out on a cross country trip.

Sincerely,

Macster.