11 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHUOA history when changing oil brand and viscosity
Leading reported evidence
Replace injectors
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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Leading evidence: 'Replace injectors' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'because i have no idea what was in there' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Fill maybe 1000 miles' (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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1
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Performed · outcome unconfirmed
After the 2/10/20 report I ran Mobil 1 for 1200 more miles before switching to DT40.
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Discussions that suspect a cause
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Suspected cause
Looking back at my first report, it may have been suspect because I have no idea what was in there before I switched to Motul.
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Discussions that contain suggestions
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Suggestion
Short change the first fill, maybe 1000 miles, to make the switch to the new formulation faster.
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Suggestion
Drain and then fill with new oil brand of your choosing.
Replace intervals will still give you relevant wear trend data
No successful repair reported for this finding.
0
Reported fixes
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Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1
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Suggestion
If a brand or viscosity switch is made, the next couple of change intervals will still give you relevant wear trend data, but judging the particular effectiveness of that oil fill can�t be done until, ostensibly, there�s no more of the previous oil type left in the engine.
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
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My question:
Does a 5 year UOA history become irrelevant if you change brands and viscosity of oil?
Thinking about changing from Mobil 1 0w-40, that has been used in my car for 18 years and 80k miles.
You have 5 years of engine wear data, regardless of what type of oil you use. If a brand or viscosity switch is made, the next couple of change intervals will still give you relevant wear trend data, but judging the particular effectiveness of that oil fill can�t be done until, ostensibly, there�s no more of the previous oil type left in the engine. Right?
Good point about residual Mobil 1 oil, I have no idea how that would skew the data derived from the new brand of oil.
The new brand will definitely have a different chemical breakdown. Your opinion is UOA will still be able to give wear analysis even though the oil sample will not be pure ?
Who has done a oil swap and continued UOA?
^^^this. wear data is still valid. Short change the first fill, maybe 1000 miles, to make the switch to the new formulation faster. I'm going through this now on my Cayenne.
It's been recommended a few times to run a very short run of about 200-400 miles of a break in oil, like BR30, when switching oils. Drain and then fill with new oil brand of your choosing.
Here’s a UOA summary containing both Mobil 1 and then a switch to DT40. After the 2/10/20 report I ran Mobil 1 for 1200 more miles before switching to DT40. I didn't do a UOA on that 1200 mile oil and the 7/3/20 DT40 UOA should be discounted as it most likely had some residual Mobil 1 contamination.
Yes. maybe unnecessary if you have several UOA's already, but its nicer to argue over too much data than not enough data. In this case, I believe it's necessary as the car is new to me, so I only have one data point from the Mobil 1 that came out of it.
Here are the last 2 UOA on my 4s. After noticing elevated fuel dilution I had new fuel injectors installed at the last oil change. Curious to see my next UOA.
Looking back at my first report, it may have been suspect because I have no idea what was in there before I switched to Motul. Now I've switched to DT40. I haven't driven a whole lot this season and I'll probably wait till next spring to change it out again. May be awhile before I have the right miles and something worth sampling. I too replaced injectors. By that point, it'll be worth dropping the sump again to see if anythings in there. I have the magnetic oil drain plug as well. Jake had told me to wait till I had a more pure sample to test and it makes sense.
This is a source reference. Confirm exact model applicability in the original material.
