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How many miles of driving does it take for new motor oil to turn from looking like fresh honey to raw sewage?

I recently had a local Honda dealer change the oil in my 2007 Honda Civic EX and they overfilled the engine with new Castrol full synthetic oil that I had supplied to them.

Following are PICs of a sample of the excess oil that I siphoned out of my engine (on the left-in the PICs) after only 3 days of driving and 189 miles!

This is compared to new-unused oil (on the right-in the PICs).

The oil I use for this car is Castrol "EDGE ADVANCED FULL SYNTHETIC" SAE 5W-20.
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Engine oil drained from '07 Honda Civic (3 days, 189 miles).



Engine oil drained from '07 Honda Civic vs. new oil.
After only 3 days (189 miles) of driving (top view)

 
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Ever done an oil change on a diesel? Black as tar the instant you start the engine.
how many miles on the motor? how often is the oil getting changed?

 
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I've never changed oil on a diesel.
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The odometer reading on 5/24/25 was 180,478.
I bought the car used in 2019, this is the 2nd oil change I've done to this car.
I've put 32,008 miles on the car so far.
The used oil in the PIC has ONLY 189 miles on it!

 
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The car has 180k, that's why the oil looks like that.
could try an engine flush to clean it up a bit
and how often are you changing it?

 
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1 oil change in 32,000 miles? There's your issue.

 
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If you haven't done an oil change in 30k you're lucky the engine still runs

 
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If you read my post, the oil in PIC has 189 miles on it.
I have changed the oil in this car (with full synthetic) about once every 15,000 miles.
This complies with recommendations from Castrol.
Flushing anything on a car is BOGUS.
I have never seen any automaker recommend flushing anything on a car! :-)
I suspect that this is just advertising hype from snake oil salespeople!

 
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15k miles is a lot more than I'd be comfortable doing, and I do almost exclusively highway. There's going to be a lot more breakdown than if you changed it even 5k miles sooner. I suspect if you pop the valve cover off, you'll see what I'm referring to.

Oil gets dark from all the carbon buildup and sludge and crap in the engine, which accumulates over time and mileage (regardless of the mileage on the oil). That's what Colin's referring to. Throw in extended oil intervals and it develops into exactly what you're showing us.

 
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I can read just fine.
The motor is high mileage, and you're going 3 times longer than i would on your intervals. That's why your oil looks like that.

 
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The engine may have 180k miles but the oil in the PIC has only 189 miles on it, AS NOTED IN THE POST.
As far as the change interval, I think Honda instructions are once every 7,500.
I am doubling that at once every 15,000 because I use Castrol FULL SYTHETIC.
Didn't I already say all of this previously? :-)

 
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You don't get it.

 
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Could you clarify your writing so I can "get it?"

 
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Read again

Most diesels are high mileage, with longer intervals

 
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You’ve said this already but you don’t really seem to be understanding what we’re explaining to you.

When you run an engine, oil degrades and will leave deposits in the engine. The longer intervals you run your oil, the more deposits are left in the engine. When you drain your oil, it does not drain the engine of all said deposits. A car with high mileage and long maintenance intervals will accumulate dons of deposits and gunk in the engine, so much so that when you add fresh oil, deposits mix into it and show what you have now.

Does that make sense? I understand it’s only been used for 200 miles, but this is the product of deposits and gunk left in the engine.

Unless you never drive in the city ever, 15k miles is too much, even for full synthetic. It’s certainly more than what the filter will be able to handle.

 
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The "oil life" (oil change interval) on this car is does not go by mileage or time, it is managed by the "Maintenance Minder" (which is run by the onboard computer).

I've known for a long time that motor oil turns black after use, I just never expected this to happen after a fresh oil change, and then only 189 miles of use! :-)

 
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I know what a maintenance minder is.
oil and filter is alot cheaper than an engine.
Been doing this for a long time.

 
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I hope we don't have to start comparing our number of years of training & certifications! :-)
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How about the question from my original post that nobody has yet answered?
- "How many miles of driving does it take for new motor oil to turn from looking like fresh honey to raw sewage?" :-)

 
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"this is the 2nd oil change I've done to this car.
I've put 32,008 miles on the car so far."
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TWO oil changes in 32,000 miles.
Castrol FULL SYNTHETIC lasts for 15,000 miles.

 
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It depends on the engine, mileage, maintenance, and driving habit. For you, apparently its less than 189 miles

 
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I've already provided plenty of relevant information, including date-stamped photographs.
So clearly, you don't know the answer to my basic question, even though you claim to have a lot of "experience." :-)

 
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We've given you the answer multiple times.
it's just an answer you happen to not like.

 
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There have been several responses to my original post so far, none of which have answered my initial basic question.
Has ANYONE in this forum ever run new oil in an engine (for 189 miles) then removed it, photographed it and asked the question, as I have done?