Black Mobil 1 in 3.6 Engine

daphe8892 · #1 (**permalink**) 10-12-08, 05:47 PM

I have an 08 CTS with the direct injection engine, purchased in May 08, has 4,000 miles on it.

Dash indicator shows 69 percent oil life remaining. Uses no oil. Oil pressure normal. Runs great. No unhappy engine noises. My first time using Mobil 1.

I changed the oil and filter at 3,000 miles then 76 percent oil life remaining, because the oil on the dipstick looked so black, and, indeed, was extremely black in the oil drain pan. Not just black. But BLACK BLACK!!! I didn't reset the "oil life remaining" indicator, but kept track of it on my own oil change record.

Put new Mobil 1 back in, used a Cadillac parts counter filter element, and now with 1,000 miles on the oil change, the oil on the dipstick shows that it is again very black.

Question: Is it normal for Mobil 1 to turn that black, that fast in other (direct or non-direct injection) engines?? Why is it turning black in this worrisome manner? Is it retaining its lubricity?? Is it okay to continue to run it? It couldn''t get any blacker.

Seems to me that it must be some combination of acid and blowby that is causing the blackness, but as I mention above, the engine performance is fine.

I am well aware of GM''s crankshaft revolution counting, oil acid/crapola dilution testing algorithms that are reflected in the "oil life remaining" readout. That aside, why is my oil turning so BLACK BLACK so QUICK QUICK???

Infrared in Idaho · #2 (**permalink**) 10-13-08, 04:57 AM

I had an 04 SRX V6 AWD for three years. I, like you used Mobil 1, but got frustrated with the oil turning BLACK so fast. I switched over to Quacker State two oil changes ago and the oil does not turn black as fast. I also add a quart of Lucus Oil Stabilizer ago with the fresh oil. No problems and I average 20K miles a year.

SvB4EvA · #3 (**permalink**) 03-31-09, 09:07 PM

I had my first oil change done by Cadillac for free, but my next one will be this weekend and I will be doing it. Ill let you know how the new oil gets over the next few days in my 3.6L

SvB4EvA · #4 (**permalink**) 04-01-09, 07:12 PM

Ok, I just changed the oil today. The old oil was BLACKKKKKKKKK as black can be. Ill check it over the next couple days and let you know.

submariner409 · #5 (**permalink**) 04-02-09, 05:00 PM

Go online and order an oil test kit from www.blackstone-labs.com . If you still have it, furnish them a sample of your yesterday's oil along with the name and weight of what it was. That's the ONLY way to tell what's now in the oil. Otherwise, run a month or so into the spring and send in a sample.

BLACK oil usually indicates a very rich fuel mixture.

SvB4EvA · #6 (**permalink**) 04-02-09, 05:20 PM

Quote:

Originally Posted by submariner409

Go online and order an oil test kit from www.blackstone-labs.com . If you still have it, furnish them a sample of your yesterday's oil along with the name and weight of what it was. That's the ONLY way to tell what's now in the oil. Otherwise, run a month or so into the spring and send in a sample.

BLACK oil usually indicates a very rich fuel mixture.

Thanks for the site, very cool! I may do this sometime or another just to see what they say.

As for my new oil, after just one day and about 15 miles on it, I can see it is slightly darker already. I will check it again in a few days.

Just FYI, my car is a 2007 CTS with ~12,500 miles. Runs excellently.

Spyke · #7 (**permalink**) 04-03-09, 09:01 AM

if the oil is changing color, it means that its doing its job: oxidates. I had once a jetta tdi and god the oil was always more black than black and never had a single problem with the engine even after 200k miles on it and changing the oil at every 10-14k miles.

A Used Oil Analysis is your best bet to really see if the oil was holding up or not. I've been doing oil analysis on all my cars for years now and its always impressive how engines are tougher and how oil is tougher.