Who can diagnose the noise on the video? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

ElementAI · 05-31-2010, 06:44 PM

http://www.youtube.com/watch?v=41gC0IPEPtQ

2000 s with 44k. Starts, runs, shifts smooth, no check engine lights, no oil leaks,
symptoms started with a vibration at 2200 rpm and noise... Now this?
Thanks
oh dealer techs and Indy techs have looked at it. Though nothing has been taken apart yet. PCNA don't want to help with diagnosis.

rob76turbo · 05-31-2010, 06:58 PM

Not sure what the sound is...but it does not sound good.
Other more experienced ears may know, but that is not a good sound.

Dragonwind · 06-01-2010, 02:36 AM

Is it louder on one side of the car? If yes you likely have a bad lifter. A friend of mine had that same noise during one of the coffee runs we did with the PCA and that's what it was.

How long has this been happening?

CHris

coreseller · 06-01-2010, 03:06 AM

My best guess would be a bad lifter. When I worked on my Boxster earlier this year the motor sat without oil in it for 3 or so weeks while I waited on parts / transmission rebuild. When I first fired it up it made a similar clacking sound for the first 10 or so minutes, it gradually went away. Other two potentials; loose spark plug, exhaust leak?

ElementAI · 06-01-2010, 03:15 AM

It has been 1.5 weeks now since it showed up. The noise does increase with rpm but obviously idling in the video.
Will find out if it is louder on one side than the other.

insite · 06-01-2010, 08:23 AM

that sounds a lot worse than a bad lifter. more like a rod knock to me.

Mike_Yi · 06-01-2010, 08:23 AM

Either a lifter, or possibly an exhaust leak. I'm leaning toward the lifter. Get it checked out before driving it more.

ElementAI · 06-01-2010, 04:25 PM

Latest from owner.

Quote:

can't tell one side vs the other, just really loud. spark plugs were changed 6 mo ago, will check them if I can. My guy thinks bearing failure at base of connecting rod. Porsche tech still thinks there is a chance it is coming from the clutch which is the reason to pull the tranny. Plan is for next week, pull tranny, will be visually obvious if that is the problem, run engine without tranny, try to locate problem, if deep in engine we know we are screwed.

Thanks for the input so far.

Topless · 06-01-2010, 05:04 PM

That is a very ugly sound. Serious interference and not a just stuck lifter. You can rent a cylinder scope to inspect internals for a possible broken valve spring (short prayer). Drain your oil through a fine screen and cut open your oil filter to look for shiny bits. A small amount of tiny particles is expected. If it looks like a grenade went off inside, the motor is done.

Jake Raby · 06-01-2010, 05:36 PM

I'd be willing to wager that its a broken valve spring.. Sounds like the piston is bouncing the valve off its seat. Could also be a shattered lifter, or even a wrist pin/ small end rod bushing.

The dealer couldn't tell what that was?? Doesn't surprise me.

Been there. Contrary to what you may have been told I can repair that.

DO NOT RUN THE ENGINE ANY LONGER!

brunoboxster · 06-01-2010, 06:08 PM

Thanks for all the responses so far. Does anyone think it is worth pulling the tranny? Does anyone think the noise can be coming from there?

Jake, I would be interested to hear what it takes to fix something like this, what the time and costs would be, etc.

I don't want to get too deep into pulling things apart if I am wasting time and money doing so.

Thanks again to all. Advice on what to do next is appreciated.

Jake Raby · 06-01-2010, 06:52 PM

Fire the car up quickly.. when the noise begins depress the clutch. If the noise goes away its in the gearbox, if it doesn't go away its in the engine.. Depressing the clutch stops the tranny internals. Pulling the tranny won't tell you much of anything. You'd be better off to pull the sump plate from the engine to inspect for debris and do the same with the filter. If you have something going south the debris will be there, take pics of that debris and I can tell you what it is, more than likely.

Your engine is low mileage and you should get a second opinion.

Its impossible to put a price tag on this, if its just a cylinder head/ related issue you may be able to get out of it for 4-5K. Nothing can be done internally with these engines for less than 3K.

I've heard lots of impending IMS failures, this doesn't fit that stereotype... I could be wrong, but the rythm of the noise sounds like something valvetrain related in the cylinder head. Remember, this engine has more than 20 different modes of failure that we've identified thus far, the IMS failure is just one of them.. Too many things are mis-diagnosed because the IMS failure is so widespread.

IF it is an IMS failure I could save the engine, more than likely but not if it continues to be driven..

Pull the serpentine belt, see if the noise goes away. Pull the sump plate and filter and look for debris. Post the pics.

brunoboxster · 06-02-2010, 03:50 AM

When I start the engine I have the clutch depressed and the noise starts right away with the motor. I am guessing that this means that it is not the tranny. Will work on getting the oil and filter out to check for metal.
Thanks again.

d

Jake Raby · 06-02-2010, 05:10 AM

With the clutch depressed the mechanical link between the engine and tranny is broken, if the noise persists its in the engine.. The rythm of that noise fits perfectly with valvetrain speed.

These engines break valve springs.