The Castrol GTX 5w-20 that I use looks very transparent, like the color of a lager beer as I'm pouring it in. After draining it out at 3k mile intervals it's a fairly dark molasses-like hue. My 8's got 15k miles total, owned since Jan '04.

Wondering if I should start changing it at 2k, or is it normal for it for the oil to get this dark?

 

It's normal. As the oil begins breaking down, it naturally gets darker. Molasses color isn't bad. If it gets real dark, almost black, you went too far between oil changes...

 

You also have to realize you are not changing all of the oil when you do an oil change for this car either. The 8 holds close to 7 quarts I think, most of which are in the coolers and lines. It is not easy if possible to drain it completely, so basically you are doing a partical change every 3k.

 

your oil will look like that after 300 miles

 

Oil color, smell, and taste are not indicative of its wear, or its remaining additive packages.

Only a UOA can determine how much of an oils additive packs are remaining, and how much containments exist.

http://www.blackstone-labs.com

 

gasoline engines all have some amount of blow-by gases that escape the combustion chamber. This introduces carbon particulates into the oil. Some of these are small enough to get past any filter, and will color the oil. This happens quickly.

 

Thanks for the replies. Sounds like 3k intervals will be okay then.

 

Mines usually that color and a quart low. i drive a lot and checking it kind of slips my mind.

 

That's too often - but if it makes you sleep better...
I'd just go with the recommended intervals in the manual.

 

try using a purolator pure one filter, not the mazda junk. your oil will look cleaner! spend the money it is worth it

 

actually the mazda filter is very good, not junk :D

i'm actually switching back to mazda oem from pure one after i finish this batch of pure one's i have :D

 

"Most" OEM filters are really good...OEM as in from the factory (not from the dealer).

If your curious about the construction, cut it up after use and post photos to the forum. Its probably a champion labs based filter.

 

just found out Advance Auto Parts have the PureOne's on sale for $4.95 this week, so I may end up sticking with PureOne's a bit longer after all :D

 

since i add about 1qt ever 1k miles my oil tends to stay a golden brown untill I change it.