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Exhaust valves made of brass?

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

Discussion summary

YOUR RESEARCHExhaust valves made of brass?

Leading reported evidence

Clean process

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No successful repair reported for this finding.

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Suggestion · Original poster

Or do people go further in cleaning process that it removes that colorization/tint as well?

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Exhaust valves made of brass?
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Leading evidence: 'Clean process' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Clean process' (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.

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Replace color it's not something

Suggestion or failed attempt

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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 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.

Suggestion · Original poster

Is that even possible - I would assume that if steel changes color it's not something that you can scrub off

Original post Read captured discussion
Exhaust valves made of brass?

Run hotter than normal

Suggestion or failed attempt

No successful repair reported for this finding.

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Reported fixes
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Unsuccessful attempts
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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

Thanks - is that colorization / yellowish tint normal on '99 engine valves - wondering if my engine has been running hotter than normal?

Original post Read captured discussion
Exhaust valves made of brass?

Test leakage

Suggestion or failed attempt

No successful repair reported for this finding.

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Reported fixes
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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

This causes some issues when for example I test leakage using water - the top part has clear oxidation after being in contact with water a few times.

Original post Read captured discussion
Exhaust valves made of brass?

Use water - the top part has clear oxidation

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

This causes some issues when for example I test leakage using water - the top part has clear oxidation after being in contact with water a few times.

Original post Read captured discussion
Exhaust valves made of brass?
Frequently discussed actions (5)

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

Clean process

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

Or do people go further in cleaning process that it removes that colorization/tint as well?

Original post Read captured discussion
Exhaust valves made of brass?

Replace color it's not something

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

Is that even possible - I would assume that if steel changes color it's not something that you can scrub off

Original post Read captured discussion
Exhaust valves made of brass?

Run hotter than normal

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

Thanks - is that colorization / yellowish tint normal on '99 engine valves - wondering if my engine has been running hotter than normal?

Original post Read captured discussion
Exhaust valves made of brass?

Test leakage

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

This causes some issues when for example I test leakage using water - the top part has clear oxidation after being in contact with water a few times.

Original post Read captured discussion
Exhaust valves made of brass?

Use water - the top part has clear oxidation

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

This causes some issues when for example I test leakage using water - the top part has clear oxidation after being in contact with water a few times.

Original post Read captured discussion
Exhaust valves made of brass?
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.

8 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: 20261027T053112Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Just wondering after seeing quite a few YT videos where both intake and exhaust valves are made of steel - also currently the Porsche "genuine" exhaust valve (99610524700) seems to be made of steel. Well, in my car '99 C4 the stem is made of steel but the top section seems to be made of brass (or coated with brass) - is that normal or have those been changed at some point of my car history? This causes some issues when for example I test leakage using water - the top part has clear oxidation after being in contact with water a few times. Luckily I have a real brass made wire brush on my bench grinder.

POST 2Original post

I assume that you have the head off and you're looking through the ports? You're seeing the valve guide.

POST 3Original post

You are going to have to post a picture of this. A brass valve in a gasoline engine would last all of about 30 seconds.

POST 5Original post

Quotes source post: 18272160

Guys, the valve guides that are pressed into the cylinder head, are made of a bronze alloy material. I encourage all of you to watch Jake Raby's "What's in My Oil" webinar that is available to Rennvision members on YouTube. The is a very educational video that covers all metals that are found within the M96 engine. (The link is below the image capture) You Tube

POST 6Original post

That coloration is combustion deposits, the valve is stainless steel.

POST 7Original post

Quotes source post: 18272675

heat and stainless produce a yellowish tint like on a motorcycle exhaust

POST 8 / ORIGINAL POSTEROriginal post

Thanks - is that colorization / yellowish tint normal on '99 engine valves - wondering if my engine has been running hotter than normal? Also wondering why I don't think I have seen that on YT videos in general. Or do people go further in cleaning process that it removes that colorization/tint as well? Is that even possible - I would assume that if steel changes color it's not something that you can scrub off

This is a source reference. Confirm exact model applicability in the original material.