I'm about to buy this car. Just checking that this sounds OK.


The truck has 101k miles on it. Engine was replaced by Porsche about half way to that. I'm buying it from my brother in law, who has owned it since almost new. If there are any doubts, I could check plugs, do a compression test, borescope, etc. Since I'm buying from my BIL, I'm not too concerned about value (so if I over-pay, no problem, it's a gift to him). But I do not want to be buying a major project.

 

On my laptop speakers, I mostly hear normal injector ticking.
However, at ~27 seconds, when you pan across the lower right, it sounds like a slower/lower pitch knock? I also hear it again at the last 2 seconds of the video.

 

I'm with 19psi - there's a secondary knock in the background there. Cold climate car? I would pay to have the cylinders boroscoped before buying that one as an engine rebuild will cost you 3-4x what it's worth.

 

I had an 04 and an 05. Both had scored cylinders.

 

Was the beige one you drove down here to pick up the ADV wheels one of those, or a newer one?

 

I think it is incorrect to attempt to or think you can diagnose something like this over a video taken with a cell phone. Another option would be to do an oil analysis. You might be missing out on a great car simply because someone hears something on the video.

 

I too hear some knock in the background - hard to say what is it.
When were the spark plugs changed last time?
You can get spark plug change/compression test & boroscope on it - so you know what is going on. Oil analysis may be also a good idea.

 

Curious - did you use the same brand gas all the time?

 

Yes, I had a beige 04 S. It had the ticking and would foul the left rear plug with oil. Knew what it was. Bought a salvage one with only 69K miles with the idea of swapping engines. It, too, had scored cylinders. Had the heads off of both of them and I have pictures. Parted out both. Bought a V6 base.

 

I was going to post almost the same thing as 19psi... It might be nothing, but I can hear something possibly out of the ordinary at 27 seconds and near the end of the video (both times) when you bring the camera closer to the front of the car and further from the top end. Can't say for sure it is piston slap, but there is definitely a lower pitch mechanical noise that sounds kind of like a diesel engine. Is that louder or fainter in person, OP? If you can try to pick up that noise better with your camera now that you know what we are listening for, that would be helpful.

Regardless of the noise, I would at the very least pull the plugs and take a look at them next, then do a compression test. If you see just one or two considerably more fouled than the others, then that is not a good sign. Oil analysis and any history of oil burning habits are helpful, but most people are (perhaps willfully) not meticulous enough with checking, adding, and documenting oil top ups.

 

Oil analysis would be a good idea. High aluminum and possibly silicon content is what you would see if a cylinder is going out. Borescope or compression/leakdown test won't find it unless you look at BDC. It has to be pretty catastrophic for it to be visible higher up the bore or be reflected in a compression/leakdown test. Likewise, if it's early in its failure, the plugs likely won't be fouled.

 

Thanks for all the advice. Keep it coming. There seems to be enough doubt here that I will look into it further. I like the truck, and would like to help my BIL unload it, but I really can't deal with another project right now.

BTW, I dug up an old post on this truck from when the initial failure occurred. Some details in there:
https://rennlist.com/forums/porsche-...the-oil-2.html
- at 44k miles in 2009, 9k miles and 2 years into my BIL's ownership
- engine seized. Diagnosed by dealer (that he bought it from) as scored cylinders. At the time, those words did not register as anything special to me, but they sure do now.
- they replaced with a crate engine. Still unclear exactly how much was new. One post in that thread suggests it is not really new, but actually rebuilt. It does have the Aluminum coolant tubes.

Of all this stuff (that I did not see until just now, well except for when I wrote it 8 years ago), the main concern is that the "new" engine was actually just a rebuild. So this particular cylinder scoring issue may be a 101k mile problem vs. a 57k mile one.

 

There no correlation to mileage and cylinder scoring.

We see it more often in colder climates or cars that see year-round use in these climates. Also cars that see longer cold starts and/or are driven mostly short distances.

Lastly, we have been able to tie this to bad/failing/dirty injectors as well.

 

Sounds normal to me. My engine has a similar secondary occasional knock, at idle only.

With 65K mi. it has done this for the past 2 years. Don't drive much, but in 2 years and 15K mi. it used 1/2 qt between yearly oil changes.

Cayennes are known for idler pulley failures. If the seller permits I would want to hear this with the serpentine belt disconnected. This is OK for a few min. test when the engine is cold.

 

Good to hear.
Yes, I can definitely do a test with the belt off. It's in my driveway now, as we figure out things.
I'll be happy to entertain any other testing suggestions.
I've been reading cylinder scoring threads on here all day so far. Am kind of concluding that the car is toast if it has the problem.

I'll still do a borescope, but have read (from the esteemed Jake) that it may not present as a problem until things are really bad, since the scoring would be at the bottom of the cylinder, mostly hidden by the piston.

Will do compression test. It sounds like leakdown (for which I'd need to finally rig up a tool for this) would not be especially useful for this suspected problem.

Will look into sending off an oil sample - sounds like that would be helpful

More info on this truck:
Lives in NorCal / bay area. Mild climate 100% since the crate engine went in. Probably never saw less than 30*F ever.
New Plugs and Coils at time of engine replacement (also transmission harness + drive belt)
Mobil1 0W-40 / Mahle filters every 5-8k miles or 1 year if less than that (except that the last change was 25 months and 2k miles ago)
New fuel pumps + filter 11k miles ago
Has seen only 4k miles in the last 36 months