shublar

I had my clutch, plate, RMS and flywheel replaced recently. While it was apart, I had the mechanic check the bores with a borescope. He said they looked pretty good but had a couple concerns.
I'm wondering how bad these are. The scope was inserted from the spark plug end.

The first pic is from Cylinder 5. Mechanic said it isn't unheard of for a little oil to get in and cause a stain. Is this a concern?
The second pic is what may be bore scoring. It is most concerning. There is just the one streak. the rest is clean. Is this the start of something that will get much worse? Is it a 10k mile problem? 50k?
The third picture looks clean. but there does seem to be some carbon build up and moisture at the bottom. The Mechanic didn't seem alarmed. Is this something to worry about?
After $5500 for all the clutch work, plugs, coils, oil and IMS seal I'm really not looking forward to a rebuild.

Car is a 2007 C2S 997 cab with 85k miles.
Thanks in advance for any advice!!!!
Scott

G.I.G.

Let me start by saying I am no expert. I can't comment on pictures 1 & 3. I guess my concern in picture 2 is that the mark looks like you would catch a fingernail if you were to run it across that surface, which isn't good from my understanding. When I had a bore scope performed as part of my PPI last year and I saw the images, it came back with streaks (I suspect all of our cars have that to some extent) but from the people I consulted with, none of them were concerned. That mark in your picture looks slightly deeper, but it could also be the reflection or camera angle.

Are you experiencing any outward signs of bore scoring (increased oil consumption, excessive smoke at start-up, sooty tailpipes, ticking sound from engine at idle, etc.)?

Just curious, but where do you live? Have you been driving the car much in colder temps?

I'll defer to others with more experience. Best of luck and please keep us posted.

Iceter

If you go to the expense of having bores scoped, make sure the tech takes multiple pics of each bore. This can often make you feel better about some odd reflection that shows up in one of the pics but not in others.

The second pic just looks like oil to me. Knowing the orientation of the camera in the bore would help a lot.

Your third pic isn't carbon fouling. I don't know what that is (looks like droplets of something) but fouling doesn't happen on the bore. Carbon collects on the piston tops and the top of the cylinder on the head and valves. The moving piston (rings) keeps the bore clean.

shublar

I have none of those symptoms except a little soot on the tailpipes. But the amount seems about the same as any of my other cars.
It doesn't seem to burn oil at all.
Thanks for the response!

PierW

Like GIG, I'm far from being an expert, but photo 2 appears to show a "groove" carved into the cylinder wall by some mechanism. The line is extremely even/consistent in width, almost as if there were a failure of a ring (loose/folded) that etched out that section. I've seen photos of "scuffing" and that isn't it, but the photos that I've seen posted (primarily by Jake) of scoring typically appear to be more spread out and don't necessarily traverse the entire length of the cylinder.

Being the owner of a '07 C4S Cab with just over 90K on the clock, this hits pretty close to home. Would also be interested to learn where the vehicle has resided and whether it spent any length of time in colder climates?

Good luck and please keep us posted.

shublar

I like in Kentucky. It's cold more than half the year. I don't drive it in snow or rain. Or really even that much when it's cold.

Thanks!

BucketList

OK I'm no expert and most of what I have gleaned come from this forum so take my comments with a bucket of sugar The first pic does look like an oil deposit, but why areen't the rings cleaning it off? Out of round piston? I would assume this is the non-power stroke side of the cylinder. Second pic to me looks like a single score at first glance but may be an oil streak left by the ring gap. I am hoping Jake comments. We are all just guessing after all. Third one is inclusive for anything. My 2c

groovzilla

I would bet big $$ that 95% of all German/USA/Japanese/Italian cars have some sign of slight scoring on their cylinder walls.
I've left out the French due to most already knowing their cars are piles of dog doo doo including the old Renault "Le Car" my dad owned - What a freakin turd mo-bile

roadie13

Yeah, borrowed my girlfriend's Renault for my driving test long time ago..except it rained, so therefore none of the lights/signals on the car worked...rescheduled that test..

docdrs

Iirc scoring generally occurs on the thrust side of the cylinder wall. Therefore this is the main area of concern and should be looked at. Any findings should be documented as to where on the cylinder wall they are present. If you are going to look should not know what you are looking for?

shublar

I'll ask the mechanic where he found it.
Does this look like bore scoring? If so, does it matter where in the cylider it is found?

Thanks!

mrdeezy

I wouldn't be too concerned. Next time have a better mechanic do it in another 25K miles.

sandwedge

The ticking sound thing has been discussed before. The dealership tech told me it can be a bad sign if more than slight and as mentioned above combined with smoke, sooty tailpipes and excessive oil consumption.

I can hear a slight ticking sound at idle after starting up but it's very subtle. The same tech told me the DFI fuel injectors give off a slight ticking sound as they fire which is more than likely what I'm hearing. He said that after hearing about so little oil consumption I've almost stopped checking the level between oil changes and no soot on the tailpipes. FWIW.

Wayne Smith

2007 was pre DFI. I don't suspect fuel injectors are involved if ticking is a concern.

4Driver4

I'd want to see another picture or two from the bottom side. I'd not lose sleep over that streak. I had similar pictures of my bores, and when I pulled the engine apart (for a different reason) they were fine.