Engine Oil Color Observation - Normal?

[blackdiamond]

Quote:

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It looked dark before because the film thickness on the dipstick is thicker when the engine is cold which given the particulate, absorbs more light than a thin coating of oil on a diptstick pulled from a hot engine of the same oil.

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I really don't know how to read a blot test, but I'm going to pull another sample when the engine is cold and see how it compares. This is a good point.

 

[blackdiamond]

http://www.mazdaforum.com/m_47975/mpage_4/key_/tm.htm#48537

Here is a link to a Mazda forum that I posted a picture of the oil in a poor mans blot test. This may be a prime example of a little too much knowledge making me paranoid.

Please view (should be on page 4) and see what you think.

 

[JAG]

I think the black inner circle is soot.

 

[blackdiamond]

Quote:

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I think the black inner circle is soot.

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What would you suspect the cause to be?

 

[tripleM]

My Mazda3 2.3 has the same oil coloration symptoms on PP.
It is unusually dark brown esp. after sitting over night.
But after 4 BlackStone & 1 TD UOA, everything is a okay.

I just think the Mazda 2.3 just works it's oil really hard but today's oil can definitely take it.

 

[JAG]

I think the soot is from the nature of the combustion in this engine due to it being a turbo and direct injected, and having engine tuning that in the U.S. emphasises low NOX emissions (meaning avoidance of running lean). Every Mazdaspeed 3 tailpipe I've seen is covered in soot. Some of that soot ends up in the oil of course.

The VW 2.0T has same above 3 engine traits and its tailpipes get sooty too. It also gives not so pretty UOAs.

Get a UOA and make sure TBN is included.

 

[BrianWC]

Sooty tailpipe? Are you sure it isn't a SAAB? Yep, same issues. Many turbo cars run pretty rich from the factory if for no other reason but for concerns over engine longevity vis a vis detonation concerns.

 

[BradC]

I've noticed the same thing with my car (2.4L Ecotec VVT).

5,500 miles on Syntec 5w30 (OLM at 44%) and it's extremely dark when checked cold. This is the first run of synthetic oil in this engine after 3 runs of dino for break-in.

However, dino at the same mileage was not as dark as the Syntec is, so I'm not sure what to make of it.

Changing it to PP in late October, if I let it go that long.

 

[salvageyardteen]

Get a UOA done, color doesn't mean too much unless its a wacky color.

 

[Triple_Se7en]

Synthetics keep engines cleaner in the long haul - so a darker oil-dipstick at the same mileage as a dino - which was used exclusively prior to this OCI - wouldn't be out of the realm of expectations.

 

[blackdiamond]

I did a UOA with Terry and have switched to a different brand of oil for the next OCI. I'll see what this one looks like and go from there.