11 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHDoes the infamous IMSB issue only affect NAs or turbos as well?
Reported or suspected cause
coolant pipes
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
This issue is the coolant pipes which are press fit into the engine case and secured with a polymer.
Does the infamous IMSB issue only affect NAs or turbos as well?
Read full discussion summary
Leading evidence: 'coolant pipes' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'coolant pipes' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Lubricate with direct, pressure fed engine oil' (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 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
It does have an intermediate shaft, but it uses a plain bearing instead of ball bearings and it is lubricated with direct, pressure fed engine oil.
Does the infamous IMSB issue only affect NAs or turbos as well?
Replace just
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
It had the oil changed just before I got it, so will be up for that soon.
Does the infamous IMSB issue only affect NAs or turbos as well?
Run of-the-mill maintenance and repairs, they are very similar
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
Well, the 996tts have their own issues, but I would say that for everyday, run-of-the-mill maintenance and repairs, they are very similar to the NA996, with the 996tt being a little higher cost to maintain.
Does the infamous IMSB issue only affect NAs or turbos as well?
Use gt1-derived engine designed by hans mezger
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
The 996 and 997 turbos use a GT1-derived engine designed by Hans Mezger.
Does the infamous IMSB issue only affect NAs or turbos as well?
Run of-the-mill maintenance and repairs, they are very similar
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
Well, the 996tts have their own issues, but I would say that for everyday, run-of-the-mill maintenance and repairs, they are very similar to the NA996, with the 996tt being a little higher cost to maintain.
Does the infamous IMSB issue only affect NAs or turbos as well?
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.
11 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: 20261027T022239Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Seriously considering a 996T since a 2009T (read no IMS) is way out of my price range.
I don't want to do an IMSB upgrade (and then do another IMSB upgrade after 75k miles).
I haven't heard about the 996 turbos being affected by the IMSB issue but not sure if that's only because there are fewer of them.
Any insight? Thks
The 996 and 997 turbos use a GT1-derived engine designed by Hans Mezger. It is a true dry sump engine, unlike the M96. It does have an intermediate shaft, but it uses a plain bearing instead of ball bearings and it is lubricated with direct, pressure fed engine oil.
It does have an issue that needs to be addressed to ensure long term reliability. This issue is the coolant pipes which are press fit into the engine case and secured with a polymer. Eventually the polymer breaks down, resulting in a sudden loss of all the coolant. Remedies include pinning or welding the pipes to prevent this issue.
Overall, it's a great engine with a long history in motor sport.
As Dennis alludes to the coolant pipe nipples are press fit/glued into the block, in I think 7 places. If you go to the 996 Turbo forum and look at the thread "High mileage 996 Turbo" you will see that T2 did some preventative maintenance on his cooling pipes at ~390k miles when he had the engine out for some oil leak repairs. Evidently the cooling tube fix was successful as he has ~469k on it with no cooling tube problems.
Timing chain failures are the biggest internal issue with the 996TT engine. Issues with a dowel found at the end of the intake cam rotating and shutting off oil flow can cause odd CELs and misfires. They can also bend rods, when the boost gets high, I am building one now due to all 6 rods being bent.
But, no IMS issues... They use a plain bearing supported IMS assembly (wonder where I got the idea for my IMS Solution, huh?)
Well, the 996tts have their own issues, but I would say that for everyday, run-of-the-mill maintenance and repairs, they are very similar to the NA996, with the 996tt being a little higher cost to maintain. The M96 has a higher chance of imploding than the Mezger, but the cost of replacing/rebuilding the M96 realistically starts at $12,000 (and can be higher of course). Figure double that if your Mezger lets go.
My '99 NA996 coupe was my daily driver through all kinds of weather and it was a fantastic car. Other than the fuel pump giving out on me once, it was as reliable as a Honda. Knock on wood, but so far, after 5 months and 3,000+ miles, I have not had to spend one nickel on maintenance on the 996tt. It had the oil changed just before I got it, so will be up for that soon. The two cars are more alike than they are different. I've mentioned it before, but bears repeating: With a NA996, you get 98% of the 996tt experience at 40% of the entry cost.
This is a source reference. Confirm exact model applicability in the original material.
