13 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHCooling fans coming on at higher temperatures than spec - why would this happen?
Reported or suspected cause
various sources give different numbers
Reported cause
No successful repair reported for this finding.
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Identified cause
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Suspected cause
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Discussions that report identifying a cause
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Reported cause
The problem is various sources give different numbers.
Cooling fans coming on at higher temperatures than spec - why would this happen?
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Leading evidence: 'various sources give different numbers' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'various sources give different numbers' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Check when the fans come' (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 suspect a cause
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Suspected cause · Original poster
Factory shop manual IIRC - therefore I would suspect DME.
Cooling fans coming on at higher temperatures than spec - why would this happen?
Check when the fans come
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Discussions
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Suggestion
I have never bothered to check when the fans come on in the Turbo.
Cooling fans coming on at higher temperatures than spec - why would this happen?
Run hotter so far it has not seemed
Suggestion or failed attempt
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Unsuccessful attempts
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Discussions
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Discussions that contain suggestions
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Suggestion
Now to be honest, I don't worry that much about the Boxster either cause while it appears to run hotter so far it has not seemed to be a problem.
Cooling fans coming on at higher temperatures than spec - why would this happen?
Test expansion tank cap, i decided
Suggestion or failed attempt
No successful repair reported for this finding.
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Discussions
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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.
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Suggestion · Original poster
After my issues with the failed expansion tank cap today and testing the new expansion tank cap, I decided to monitor the temperature while driving around (using the climate control hack) and found them high.
Cooling fans coming on at higher temperatures than spec - why would this happen?
Test expansion tank cap, i decided
No successful repair reported for this finding.
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Reported fixes
0
Unsuccessful attempts
1
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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
After my issues with the failed expansion tank cap today and testing the new expansion tank cap, I decided to monitor the temperature while driving around (using the climate control hack) and found them high.
Cooling fans coming on at higher temperatures than spec - why would this happen?
Use climate control hack) and found them high
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
After my issues with the failed expansion tank cap today and testing the new expansion tank cap, I decided to monitor the temperature while driving around (using the climate control hack) and found them high.
Cooling fans coming on at higher temperatures than spec - why would this happen?
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.
13 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: 20261027T003124Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
After my issues with the failed expansion tank cap today and testing the new expansion tank cap, I decided to monitor the temperature while driving around (using the climate control hack) and found them high.
I checked when I got home, idling in the garage, and discovered that the low speed fans do not switch on until the climate control hack show 103C and my Durametric shows 100.5C (it appears that the climate control is 2.5C to 3C high across the range).
This fan behavior seems a bit strange as they are supposed to come on at 96.75C for the low speed - I did not bother to wait for the high speed fans to come on fearing how hot it might get. I believe that this situation has always existed, even prior to the events today.
Interestingly the Durametric was also showing the following error codes
P0481 - Fan output stage 2 - open circuit
P1674 - Engine compartment purge fan,
both of which I attributed to the recent fan hack
Any ideas?
Many thanks
P0481 - Fan output stage 2 - open circuit
P1674 - Engine compartment purge fan,
First one an open circuit could be a bad connection or broken wire.
Second fault refers to the fan on the rear spoiler lid.
Not sure of the way things are wired but if it's a series connection one fan having a bag connection would stop the other fan in series from working.
My low speed fan also does not come on until 103C on the climate control hack. I never checked it before the fan hack but I thought it came like that. What temp is high speed supposed to be switched on?
However, they all work. I am pretty sure it's just the fan hacks which trigger the error code when you bypass the normal circuit with the manual toggle to turn on the fans
Is this according to the climate control temp gauge or Durametric temp? I had my ECU flashed several years ago so I don't know if these settings were changed in the flash.
Factory shop manual IIRC - therefore I would suspect DME. The climate control hack is not accurate and this has been stated by Loren and I can confirm that mine is about 2.5C to 3 C high at all times.
I understand that climate control it is not the most accurate. However, if everyone goes by the climate control hack, it gives us a baseline to work with. Just like using a scale which needs calibrating, if everyone uses the same scale, we still can determine if there is a variance.
I'm not usually one to doubt Loren, but I've been reading over this section of the manual recently for my own problems. As I recall Stage 1 comes on at 100C and Stage 2 comes on at 105C. There is also a dependance on some other factors (AC operation, outside temp), but those are the thresholds I recall. The 100C seems to correlate well with your Durametric reading.
Can I ask the source? I would never doubt him either, but we have empirical evidence that supports your information and it would be very valuable to be able to reference the source.
The problem is various sources give different numbers. They differ, not by much, but they differ. Loren's numbers are as good as anyone's and probably better than most.
My source (Bentley manual for Boxsters) says the fans come on low speed at 100C (212F) and high speed at 216F (102C). (A high pressure in the A/C system I guess indicating extreme cooling is required which triggers the fans into high speed mode.)
I have confirmed the low and high speed temp trigger by monitoring the coolant temp using an OBDII code reader/data viewer.
However, the above is from a manual for the Boxster (up to year 2004 IIRC). It is not for any 996 model.
I can't find any info on when my Turbo's fans come on although I note they are listed at 3 stage fans, suggesting there are 3 speed ranges vs. 2 for my Boxster. I have never bothered to check when the fans come on in the Turbo.
From observing Obd data collected while driving I know the engine runs considerably cooler than the Boxster -- under the same driving/operating/ambient temperature conditions -- and I just don't worry about the Turbo and its coolant temperature as much. (Besides it has an oil pressure gage which I do pay attention to and even in 118F ambient temp has not given me any reason to worry.)
Now to be honest, I don't worry that much about the Boxster either cause while it appears to run hotter so far it has not seemed to be a problem.
Sincerely,
Macster.
