20 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHExpansion tank cap failing?
Leading reported evidence
Clean radiators
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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Discussions that performed work without a confirmed outcome
1
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0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
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Suggestion · Original poster
However, temps on the climate control hack to the DME were showing 94 - 97C in traffic and 92C in clean air and the ambient temperature ranged from 73 to 80F.
Leading evidence: 'Clean radiators' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'cap and not' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Clean air and the ambient temperature ranged' (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
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Performed · outcome unconfirmed · Original poster
I cleaned up everything last night and replaced the cap - what I thought was good and tight.
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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Performed · outcome unconfirmed · Original poster
Just ran the car around for about 45 mins with the new cap mostly moderate speed driving 30 to 50 mph.
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 suspect a cause
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Suspected cause · Original poster
I hope it was the cap and not that my actions last night caused the tank to crack somehow.
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 suspect a cause
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Suspected cause · Original poster
If you look closely the seal is pretty old and had a relatively deep impression in it - so I am going to guess it was probably the issue.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
Clean air and the ambient temperature ranged
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
However, temps on the climate control hack to the DME were showing 94 - 97C in traffic and 92C in clean air and the ambient temperature ranged from 73 to 80F.
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.
20 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: 20261026T130754Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
Does this look like a failing expansion tank cap?
My part # is 996-106-447-01 and Pelican shows 996-106-447-04-M100 - which I assume is a revised and newer part - based on the 04 at the end.
I have cleaned it up to see if there is a leak, but for the $30, maybe it just makes sense to replace.
Query - Would this kind of failure cause operating temperatures to be higher than normal?
Ordered a new one this morning. Pick up this afternoon.
I cleaned up everything last night and replaced the cap - what I thought was good and tight. I guess not, I dumped a bunch of coolant this morning as I pulled in the parking lot at work. I hope it was the cap and not that my actions last night caused the tank to crack somehow.
Are you saying you put the new cap on and the system dumped a lot of radiator fluid?
If a cooling system doesn't keep the required pressure the fluid is more prone to boil. Once boiling starts and pressure is release through a leak then its like a pot boiling and it goes into an over boil hence more coolant loss.
I couldnt see the cracks in my tank till I removed it...hairline fractures in rear of tank...that would only spring a leak under pressure. If I were you Id replace the coolant reservior....mine was about that yellowed when it developed small cracks.
Next time washing and waxing make sure you wash the rim of your engine comparment like where the picture shows and other points developing a coating of grime. I like using a spray on carnuba by eagle 1 that you can spray on when the car is still wet then shami off the water and the area is waxed.
No, my mis-communication. I cleaned the old one up last night and put it back on (had no apparent issues to that point). I am going to assume that in doing so I remove the gunk that was holding it together and as a result it dumped coolant this morning.
I managed to get the car home without it leaking again, but after I stopped and parked it, I could hear the pressure venting from near the tank opening. If you look closely the seal is pretty old and had a relatively deep impression in it - so I am going to guess it was probably the issue.
I just picked up the new cap and will see if that solves the problem, if not then I will replace the tank.
If that's the original tank, I'm suprised it lasted 10 years. It could have been that your re-tightening the cap made a better seal and the pressure caused a previously unseen crack(s) to fail.
Just ran the car around for about 45 mins with the new cap mostly moderate speed driving 30 to 50 mph. No leaks evident from the new cap or from the expansion tank for that matter.
However, temps on the climate control hack to the DME were showing 94 - 97C in traffic and 92C in clean air and the ambient temperature ranged from 73 to 80F. These seem a bit high, so I am a bit puzzled. I guess it's time for a pressure test and perhaps a new expansion tank.
