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Borescope from top - oil in cylinders ok?

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7 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCHBorescope from top - oil in cylinders ok?

Leading reported evidence

Check intake manifold

Performed · outcome unconfirmed

No successful repair reported for this finding.

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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that performed work without a confirmed outcome
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Discussions that contain suggestions
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0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed · Original poster

I checked the intake manifold for oil- it is dry.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?

Suggestion

Check the intake manifold for oil, too.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?
Frequently discussed work

Check bank one and they looked the same

No successful repair reported for this finding.

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Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

They were fouled with oil so I decided to check bank one and they looked the same.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?
Read full discussion summary

Leading evidence: 'Check intake manifold' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Check bank one and they looked the same' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.

Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.

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1 matching discussions · 7 captured posts examined · 0 partial discussions

Compare 4 other evidence results

Replace plugs

Performed · outcome unconfirmed

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that performed work without a confirmed outcome
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed · Original poster

I replaced the plugs.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?

Check bank one and they looked the same

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

They were fouled with oil so I decided to check bank one and they looked the same.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?

Check compression and aos

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

I'm going to check compression and AOS to try to figure out where the oil is coming from.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?

Check cylinders while i had the plugs out

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

I got a borescope to check the cylinders while I had the plugs out.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?
Frequently discussed actions (8)

These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.

Check bank one and they looked the same

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

They were fouled with oil so I decided to check bank one and they looked the same.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?

Check compression and aos

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

I'm going to check compression and AOS to try to figure out where the oil is coming from.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?

Check cylinders while i had the plugs out

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

I got a borescope to check the cylinders while I had the plugs out.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?

Check intake manifold

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that performed work without a confirmed outcome
1
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed · Original poster

I checked the intake manifold for oil- it is dry.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?

Suggestion

Check the intake manifold for oil, too.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?

Replace air oil separator

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

At some point I will replace the AOS but I would prefer to wait if it's not urgent.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?

Replace plugs

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that performed work without a confirmed outcome
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed · Original poster

I replaced the plugs.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?

Run some pea injector cleaner

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

Next I'm thinking of running some PEA injector cleaner to try to clean up the deposits I saw on the valves while scoping.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?

Test air oil separator

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

I got a manometer to test the AOS.

Original post Read captured discussion
Borescope from top - oil in cylinders ok?
Coverage and how to read this overview

Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.

7 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.

  • Rennlist: 1 discussions

0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.

0 acknowledgements have no verified action link; they do not establish a repair result.

Generation: 20261026T191851Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Hi all, first thread here. I've owned my 2003 C4S for almost a year. ~55k miles. I did UOA after purchase and it came back clean. Recently I got misfire codes P0300, P0304, P0305, and P0306, so I pulled the plugs on bank two. They were fouled with oil so I decided to check bank one and they looked the same. I got a borescope to check the cylinders while I had the plugs out. It looks like there is some light scoring, example of cylinder 6 below. All six cylinders have some oil pooled which I didn't expect. Is this normal? Do I need to do something to get the oil out before restarting? I'm going to check compression and AOS to try to figure out where the oil is coming from. More pics and videos here . showing the excess oil below

POST 3Original post

I'm guessing AOS? Can you do a manometer test?

POST 4 / ORIGINAL POSTEROriginal post

I tried to scope the intake but it was too hard to get a clear image, so I probably need to disassemble. I don't have a manometer, but I'm thinking about getting one.

POST 5Original post

That doesn�t look like a significant amount of oil to me. I�m certainly not an expert in what people find when they scope the cylinders.

POST 6 / ORIGINAL POSTEROriginal post

I replaced the plugs. Seems to be running well. I checked the intake manifold for oil- it is dry. I got a manometer to test the AOS. On a cold start I get 8.5 in H20 for a moment and then it settles down to about 7 after a few minutes. After warmed up I get between 6 and 6.3 in H20. These numbers appear to be slightly high but maybe not terrible? The oil cap comes off relatively easily and I get a whistling noise, maybe a 100 rpm increase in idle (not much), and it sounds a bit rough but not close to stalling. From what I've read, this is normal or maybe suggests early/limited failure of the AOS. At some point I will replace the AOS but I would prefer to wait if it's not urgent. Next I'm thinking of running some PEA injector cleaner to try to clean up the deposits I saw on the valves while scoping.

POST 7Original post

I had the same. AOS. Hopefully the same for you

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