# Solid black grit in engine oil **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** saab, 9-3\ **Created:** [September 13, 2018, 1:43am UTC](https://community.cartalk.com/t/solid-black-grit-in-engine-oil/124903 "2018-09-13T01:43:00Z")\ **Posts on this page:** 5\ **Page:** 2
**Author:** ![VOLVO-V70](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@VOLVO-V70](https://community.cartalk.com/u/VOLVO-V70)\ **Post date:** [September 13, 2018, 4:35pm UTC](https://community.cartalk.com/t/solid-black-grit-in-engine-oil/124903/21 "2018-09-13T16:35:18Z")
> [@Nick\_Law](#): > > im thinking of getting a v70. good looking cars and safe. are they reliable? I think 2010 was the last year for the V70 so you are thinking of buying another vehicle with a limited dealer network that is at least 8 years old . Forget it . If you have read anything here is that used luxury vehicles are expensive to maintain and that does not seem like anything for you. ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/48514_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [September 13, 2018, 5:53pm UTC](https://community.cartalk.com/t/solid-black-grit-in-engine-oil/124903/22 "2018-09-13T17:53:41Z")
> [@Nick\_Law](#): > > turbocharged > [@Nick\_Law](#): > > what else can it be? I’m thinking that it could be some “coked” residue from the turbocharger that has gotten into the crankcase, and that would not be a good thing. 🤔 ---
**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\ **Post date:** [September 14, 2018, 1:49am UTC](https://community.cartalk.com/t/solid-black-grit-in-engine-oil/124903/23 "2018-09-14T01:49:50Z")
This is a turbocharged engine? Oh my. Then I’m thinking the same as VDC above. Whatever the source, turbo unit or elsewhere, some kind of carbon/coke deposits have broken loose. Carbon/coke can be differentiated from most plastics b/c It won’t melt at any reasonable temperature. Years ago I had a summer job where I’d have to test the melting point of certain precursors of plastic. What we used was sort of a hot plate equipped with a thermocouple and a microscope. We’d turn the hotplate up and watch when it melted, then we’d note the temperature from the thermocouple. OP could figure out a way to do something like that I suppose. ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [September 14, 2018, 2:27pm UTC](https://community.cartalk.com/t/solid-black-grit-in-engine-oil/124903/24 "2018-09-14T14:27:27Z")
> [@George\_San\_Jose1](#): > > We’d turn the hotplate up and watch when it melted Not all plastics “melt”. Thermoplastics do melt, thermoset plastics don’t - think bakelite or phenolics. They turn to a crusty burnt product much like the OP describes. I think that lends credence to yours and @VDCdriver’s “turbo oil coke deposits” theory. ---
**Author:** ![VDCdriver](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/vdcdriver/32/48514_2.png) [@VDCdriver](https://community.cartalk.com/u/VDCdriver)\ **Post date:** [September 14, 2018, 2:40pm UTC](https://community.cartalk.com/t/solid-black-grit-in-engine-oil/124903/25 "2018-09-14T14:40:46Z")
> [@Mustangman](#): > > I think that lends credence to yours and @VDCdriver’s “turbo oil coke deposits” theory. Thanks, although–for the sake of the OP–I hope that I am wrong with that theory. Here is a possible scenario: The previous owner changed oil infrequently, “wailed on it”, and did not consistently use the proper specification motor oil, thus leading to “coked” oil in the turbocharger. Now that the OP has changed the oil 3 or 4 times in 13k miles, using **Mobil** -1 (NOT “Mobile” 1 😉), some of the coked deposits in the turbo have been loosened, and have been washed into the crankcase. [Previous page](https://community.cartalk.com/t/solid-black-grit-in-engine-oil/124903.md?page=1)