4 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHP0021 and Noises
Reported or suspected cause
possible
Reported cause
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
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 report identifying a cause
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.
Reported cause · Original poster
This issue is possible on most Mezger engines, but so far have only seen this discussed on 996TTs.
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
Unfortunately, the solution for this requires an engine teardown and rebuild to replace the intermediate shaft and gear use good Loctite on the retaining bolts.
Leading evidence: 'possible' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'possible' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Replace intermediate shaft and gear' (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.
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
Unfortunately, the solution for this requires an engine teardown and rebuild to replace the intermediate shaft and gear use good Loctite on the retaining bolts.
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
The noise seems to change with the RPM, however, it goes away depending on the engine load.
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
A better and more expensive alternative is to use the intermediate gear set from the GT3, which is a one-piece part.
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
Unfortunately, the solution for this requires an engine teardown and rebuild to replace the intermediate shaft and gear use good Loctite on the retaining bolts.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
Replace intermediate shaft and gear
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
Unfortunately, the solution for this requires an engine teardown and rebuild to replace the intermediate shaft and gear use good Loctite on the retaining bolts.
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
Unfortunately, the solution for this requires an engine teardown and rebuild to replace the intermediate shaft and gear use good Loctite on the retaining bolts.
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.
4 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Pelican Parts: 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: 20261026T205155Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Hello,
I have a 996tt which is making knocking/rough sounds at idle and while driving. The noise seems to change with the RPM, however, it goes away depending on the engine load.
Here is the information I have gathered so far:
- Durametric shows code P0021 - Porsche fault code 325 - Camshaft position with respect to crankshaft bank 2.
From what I have read it seems like this could be caused by a “spun cam” where the inner sleeve of an intake cam rotates, blocking oil flow used to advance the camshaft. Some details here
https://www.joeleggs.com/blog/997-turbo-gt2-camshaft-adjustment-failure-fault-code-p0021
- Camshafts deviation for bank 2 is ~13 degrees, while bank 1 is near 0.
- Occasionally code seen these codes, however, they have not persisted:
P1349 - Camshaft adjustment bank 1 Below limit
P1358 - Camshaft adjustment bank 2 Below limit
- When I activate the variable lifter with the Durmatric the idle becomes rough and there is a clunking sound.
I am preparing to open camshafts in December, but ahead of this, I want to anticipate what I might encounter.
Any thoughts on what could be going on?
Thank you!
I wanted to provide an update on this thread. I have narrowed down the issue I described above to likely be caused by timing gear separation from the intermediate shaft. I can discuss how I narrowed it down to this if anyone is interested, but I have eliminated the possibility of failed lifters, spun cam sleeves, worn oil control rings and housings, defective cam phasers, defective solenoids, worn chain guides, stretched chains, and failed chain tensioners.
Timing gear separations are apparently a rare occurrence, but it happens when the bolts holding the timing gear to the intermediate shaft come loose. This issue is possible on most Mezger engines, but so far have only seen this discussed on 996TTs. See these links where other people have documented this same issue.
Here is a photo I found of this same issue taken from the link below:
http://www.911uk.com/files/p4121363_874.jpg
911uk.com - Porsche Forum : View topic - 996 turbo IMS failure
https://www.pistonheads.com/gassing/topic.asp?t=1121214
Similar to what was described in the above links, the rattling is most prominent when the engine is decelerating from around 3k on down, and when the intake cam high lift is activated.
Unfortunately, the solution for this requires an engine teardown and rebuild to replace the intermediate shaft and gear use good Loctite on the retaining bolts. A better and more expensive alternative is to use the intermediate gear set from the GT3, which is a one-piece part.
In my case, I will eventually have to dismantle my motor to confirm my suspicions. For now, the car will not be driven.
Has anyone else encountered this issue on their 996TT/997TT motors or any air-cooled motors, and could you please contribute your experience here?
Thank you,
Jeff
Hello,
I just wanted to provide closure to this post. I have successfully resolved the issues I described above, and thankfully, they were not related to the timing gear. Please refer to my update in this thread for further details -
Cam Position Deviation on 996TT
This is a source reference. Confirm exact model applicability in the original material.
