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Discussion Starter #1
I dont know how many of you change your own oil, but I have noticed that the used oil is very very dark. And im not positive, but I could swear that I saw a little sludge on my last change.
Ive been using Mobil 1, and have changed the oil at 2,000 miles, and at 5,000 miles. At 2,000 the oil was black, but still relatively thin. At 5,000, it was extremly dirty, as black as night, and very very thick.

Im very concerned about sludge, and my thinking is that the filter isnt doing a good job, with the combination of a nasty air/fuel curve, and a turbo that probably breaks down the oil with ease from high heat.

Thoughts?

Anyone try a different filter yet? Im willing to bet Ford/Mazda uses the same filter for the 6 as the speed6, which is a big no no imo
 

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Next time, send it in for analysis. Then you can find out for sure instead of just guessing based on how it looks.
 

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Discussion Starter #3
Oh yea forgot to add...

Audi had a sludge problem that was killing A LOT of 1.8t's. They ended up changing the filter several times, and now use filters that look like they belong on an 18 wheeler. The thing is about 4-5 times the size of our filter.
 

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That analysis should help you determine if it's sludge or not.
 

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Synthetic oil will be darker/blacker than regular oil when you change it. Sludge? Well, I'd highly doubt it with synthetic oil, especially since you not doing extended mileage betwen oil changes.
 

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Discussion Starter #8
Synthetic oil will be darker/blacker than regular oil when you change it. Sludge? Well, I'd highly doubt it with synthetic oil, especially since you not doing extended mileage betwen oil changes.
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I dont know if it was sludge, but Ive persoanlly changed oil on about 10 different cars, and this oil "looked" the worst, also smelled the worst :D

The oil Audi uses is synthetic blend, and they were replacing motors left and right from sludge. I believe Mazda uses the same oil.
 

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I dont know if it was sludge, but Ive persoanlly changed oil on about 10 different cars, and this oil "looked" the worst, also smelled the worst :D

The oil Audi uses is synthetic blend, and they were replacing motors left and right from sludge. I believe Mazda uses the same oil.
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I thought you said you used Mobil 1? Mobil 1 does look darker/blacker than regular oil for sure. I have seen it in many cars look that way. Darker oil also means it is doing its job of cleaning the engine. Not sure about the sludge issue though. Also, if Mazda is using a synthetic blend, then they are probably using a Motorcraft 5W-20 synthetic blend.
 

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I wouldn't worry about it, it sounds normal. I've taken my cars on Synthetic to 15K between changes, I only change the filter once in between oil changes. I've had no issues. My last car had I boutgh new used synth changed every 15k or so.. I got ride of it with 80 k and you still saw baremetal when you took off the valve cover..
 

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Discussion Starter #12
Depends a lot on your driving habbits. .

I've got 4,000 miles on my original oil and it still looks new, I drive 90% highway miles.
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What oil are you using?

I admit though, most of my driving is in traffic, and I wind her up to 5500 a lot, I guess its my driving..
 

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The oil turns black due to the detergents in the oil absorbing what is essentially the byproducts of an internal combustion engine (aka dirt). The oil turning black shows that it is doing it's job. If you were to use non-detergent oil (can you still get it anymore?) it would stay looking nice and clean for a long time.:D

(Of course your engine would be full of crap.):laugh:
 

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Discussion Starter #15
The oil turns black due to the detergents in the oil absorbing what is essentially the byproducts of an internal combustion engine (aka dirt). The oil turning black shows that it is doing it's job. If you were to use non-detergent oil (can you still get it anymore?) it would stay looking nice and clean for a long time.:D

(Of course your engine would be full of crap.):laugh:
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I know why the oil turns black, but the fact that its cleaning out so much dirt is what worries me, ie.. the same exact oil in my 350Z is golden brown, so either the filter is not as good, or some how it gets way more dirt in the engine
 

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I know why the oil turns black, but the fact that its cleaning out so much dirt is what worries me, ie.. the same exact oil in my 350Z is golden brown, so either the filter is not as good, or some how it gets way more dirt in the engine
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Perhaps part of this was due to your spark plug issue?
 
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