Blakc Mobil 1 in 3.6 Engine

daphe8892 · #1 (**permalink**) 10-12-08, 05:49 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???

KenD245 · #2 (**permalink**) 10-12-08, 06:40 PM

I have a 2009 CTS with direct injection and 3200 miles.

I just checked the engine oil and it is at the full mark and is clean; not crystal clear but clean. The oil life is at 73 percent.

I would be very concerned if mine was black/black. I would certainly take it to the dealer and complain; something is not right.

yatesd · #3 (**permalink**) 10-12-08, 06:41 PM

I haven't really looked at the oil closely, but I really doubt there is any issues to be concerned about. I would also argue most responses to this question would be too subjective (how black is black).

I have never used one of these testing labs, but I believe it is the only way to really get the answers you seek.

http://www.blackstone-labs.com/index.html

Seems like it will cost you less than $25 to find out if you should be concerned:
http://www.blackstone-labs.com/free_test_kit.html

If someone does decide to do this analysis, please post your results!

redvett94 · #4 (**permalink**) 10-12-08, 08:11 PM

The dip stick is black but the oil on your finger or paper towel should be clear. Mine had 5000 mi and still was plenty clear.
Reset the OLM so you have accurate oil life usage.
Synthetic oil does not brake down like conventional oil and changing too often is a waste of resources. Even dark or black oil is still good.
Your OLM is a better judge of oil condition than you looking at the discolored oil.

valcor · #5 (**permalink**) 10-12-08, 09:58 PM

Ny 09' CTS4 DI has 3200 miles and the oil looks nice light brown/gold color! I will have is check by the dealer!

dubeiram · #6 (**permalink**) 10-13-08, 09:17 AM

Quote:

Originally Posted by yatesd

I haven't really looked at the oil closely, but I really doubt there is any issues to be concerned about. I would also argue most responses to this question would be too subjective (how black is black).

I have never used one of these testing labs, but I believe it is the only way to really get the answers you seek.

http://www.blackstone-labs.com/index.html

Seems like it will cost you less than $25 to find out if you should be concerned:
http://www.blackstone-labs.com/free_test_kit.html

If someone does decide to do this analysis, please post your results!

I have used blackstone to get the oil checked on my pick up.. they do a nice job.. $22.50... good piece of mind.. anyway dark oil is the soot particles being held in suspension by the oil and has no impact on its lubrication properties... however for $22.50 and a $1.85 postage..Blackstones sends you a very nice plastic container that has eveything you need to collect a sample.. and the techs are great... go over the results with you... the best $24.35 you will ever spend on your car... I was going to do this perhaps every other oil change... just think the $$ you will save by doing your own oil change pays for the analysis...

C6Vette · #7 (**permalink**) 10-13-08, 05:06 PM

I wouldn't worry about it. Remember, your car is new, there is going to be a lot of very fine particles suspended in the oil. The oil has a lot of cleaning agents. If you look at a small bit, on your finger it will look somewhat clear. If you look at a lot of it then it will appear very black. I changed my oil around 3K after initial break in. The oil was very black. It doesn't get a lot better if you change it every 8K thereafter. My Vette oil comes out very dark as well. I wouldn't worry.

daphe8892 · #8 (**permalink**) 10-14-08, 08:46 PM

Thanks for the great comments and advice. I probably will continue to change it every 3,000. I think I also will put Mobil1 in my wife's new Lexus next oil change, and see if it turns black as quickly and completely.

I know that oil being black doesn't necessarily mean it is not doing its lubrication job. But I've never seen oil this BLACK, this quickly in a new car before. It has occurred to me that perhaps the PCV valve is defective or installed wrong, thus trapping crankcase gasses in the crankcase. I'll look at that as I get time.

BLACK CTS · #9 (**permalink**) 10-14-08, 08:53 PM

I too was surprised at how black and how fast my oil got after the change. The dipstick is black so it is kind of deceiving.

dubeiram · #10 (**permalink**) 10-15-08, 09:54 AM

Quote:

Originally Posted by daphe8892

Thanks for the great comments and advice. I probably will continue to change it every 3,000. I think I also will put Mobil1 in my wife's new Lexus next oil change, and see if it turns black as quickly and completely.

I know that oil being black doesn't necessarily mean it is not doing its lubrication job. But I've never seen oil this BLACK, this quickly in a new car before. It has occurred to me that perhaps the PCV valve is defective or installed wrong, thus trapping crankcase gasses in the crankcase. I'll look at that as I get time.

does this car even have a PCV valve?? my truck and sons car dont..

yatesd · #11 (**permalink**) 10-15-08, 09:31 PM

Quote:

Originally Posted by dubeiram

does this car even have a PCV valve?? my truck and sons car dont..

I don't think it does. Here is a quote from GM's media site:

"Cam phasing pays big dividends in reducing exhaust emissions by optimizing exhaust valve overlap and eliminating the need for a separate exhaust gas recirculation (EGR) system."

z06bigbird · #12 (**permalink**) 10-15-08, 11:34 PM

It has been my experience that some cars just turn their oil black no matter what you do. Not very many do that, but it does happen, and I, like most here, do not know why. I have noticed, however, that this happpens with synthetic oil. I am sure that regular oil turns black too. I will ask some of my favorite GM service mgrs within the next week or so.

daphe8892 · #13 (**permalink**) 10-17-08, 04:20 PM

PCV valve -- does it have one?? Good question. I haven't had time to look yet. But it must have some system or other to get crankcase gases -- the blowby on the power stroke -- out of the crankcase.