Hello guys!
I did first oil change on my newly acquired LS and when I first removed the drain plug, I kind of freaked out - oil was dark red color, I thought that I'm draining transmission, but it was definitely engine oil.
What could cause oil turn red?
Thanks!

 

The transmissions on these cars have a drain plug but if you are sure that it is from the oil pan then someone either made a big mistake or they used a dye in it maybe to find a leak.

 

Isn't Royal purple a red oil? Not sure have not used it. I know in the old days there was Royal triton and it was purplish.

 

http://www.royalpurpleconsumer.com/r...aqs/motor-oil/

It is purple, go down to the question about its color.

 

There are a variety of motor oils that will begin to have a reddish hue as they cycle with age to brown. Some long sitting cars there can be a chemical reaction that may cause this. Other possibilities are quick change oil places that fill with incorrect fluids. If you have enough get it analyzed to know for sure. Glad you changed it out. There are a variety of threads on other forums about reddish engine oil.

 

Did you remove the plastic engine under cover with the several 10mm bolts to access the oil pan? I'm having trouble believing you didn't drain the transmission. No used engine oil should have any sort of red tint, especially a red tint that is easily noticeable.

 

Thank you for your replays!

After I saw red oil coming out of the drain plug, I immediately put it back and checked engine dip stick - level went down. I'm absolutely positive that it was engine oil. After it drained down I checked the dip stick again and it was dry.
I just hope it was some weird oil and not the transmission fluid in the engine.

 

In the old days that was a method of flushing the engine to fill it with ATF and run it for a bit, then drain it.

 

I always thought the reddish hue was due to the way light refracts/reflects off the oil stream as it leaves the pan. I never really thought about it. I think it has more to do with the way the oil or its additive package ages and/or reacts with heat cycles, picks up contaminates, etc.

I've seen instances of this over the past 40 years on my own vehicles as well as others. I don't think it's anything to get excited about.

 

I thought that was kerosene that people used in the old days for flushing?

 

Marvel Mystery Oil too. In the 60's, 70's and 80's, lots of those snake oil remedies carried on. Even now I come across guys from that era talking up these in current cars. Brings chills to me when I hear ATF being put into engine oil to clean. That's not saying it won't, just that a properly maintained engine should not require the cocktail mix. Current oils tend to be very clean when maintained at good intervals.

 

I never said it was the only method, just A method. I remember the auto parts place telling my dad to do that in his 57 chev truck with a 235 that was a sludged up mess. I don't remember how well it worked.

 

I did the oil change yesterday and found that the color of drained oil was brownish. I do not know how reddish the color of your oil that is drained was like but I've done oil change all my life on this car and this is the first time I've noticed the brownish color/ One thing I did differently on this oil was that I put in synthetic oil and drove for 10K miles before doing this oil change. When I first read your posting, I thought the reddish color of oil was the most strangest thing I've heard and I am not sure how reddish the color of oil was but I am guessing the villain is the synthetic oil.