Oil turns dark quickly

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2002 Ford Ranger Edge 3.0L 76k

I know that oil turning a darker shade or two doesn't mean the oil is spent completely. However, I normally associate that with oil that has been in service awhile. While I have read in articles online about this happening due to soot being removed via the oil, in my case it is happening in less than 1k miles into OCI.

The truck calls for 5w20, but I have been using 5w30 Castrol edge since I got the truck about a year ago with 66k on the clock. It literally looks like dark roast coffee within the first 1k miles and it got me to wondering why. Every vehicle I have owned in the past never did this regardless of miles from new to well used(170k).

Is this a sludgy motor being cleaned by synthetic oil? Or is it incomplete combustion hence the soot? My commute to work is 64 miles round trip with 25-27 miles highway and the rest city.

This is the first vehicle I have ever used Castrol synthetic in and I'm also wondering if it is the "DNA" of the oil that may be causing it.
 
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Could be cleaning from the previous owner. Unless you know the history , could be they went long on conventional oil, and its cleaning. Could also be a bit of blow by somewhere. I'd run some techron through the gas, that should clean up carbon in the combustion chambers. Try a different oil next time and see. Then go back to the Castrol . Even if its the Castrol, we still don't know what that means. Cleaning or just how the oil changes color due to the base oil and add pack.
 
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Originally Posted by spasm3
Could be cleaning from the previous owner. Unless you know the history , could be they went long on conventional oil, and its cleaning. Could also be a bit of blow by somewhere. I'd run some techron through the gas, that should clean up carbon in the combustion chambers. Try a different oil next time and see. Then go back to the Castrol . Even if its the Castrol, we still don't know what that means. Cleaning or just how the oil changes color due to the base oil and add pack.


The lady I bought the truck from took it to a quick lube joint near her home and always had Castrol conventional 5w20 put in and normally got a champ filter(on it when I got the truck anyway). She said she never had the "expensive stuff" put in it when I inquired about oil changes.
 
I am not sure why this happens either but I have noticed it with some oils and not with others. I thought I had a bad filter with a stuck bypass so I changed the filter but it did not change anything. My problem was with QS about 10 years ago and I changed to M1 and the problem went away. I have since tried QS again and did not have the issue. It looked like the oil was oxidizing.
 
Originally Posted by NavyVet88
Originally Posted by spasm3
Could be cleaning from the previous owner. Unless you know the history , could be they went long on conventional oil, and its cleaning. Could also be a bit of blow by somewhere. I'd run some techron through the gas, that should clean up carbon in the combustion chambers. Try a different oil next time and see. Then go back to the Castrol . Even if its the Castrol, we still don't know what that means. Cleaning or just how the oil changes color due to the base oil and add pack.


The lady I bought the truck from took it to a quick lube joint near her home and always had Castrol conventional 5w20 put in and normally got a champ filter(on it when I got the truck anyway). She said she never had the "expensive stuff" put in it when I inquired about oil changes.



I agree with spasm.....

Just me but I'd change this run out at 3k miles.... Next run 4-5k miles.... Then next run 5-6k miles.
 
IME oil can darken quickly after switching brands or types of oil. I had been running Magnatec in my Cadillac for the past three or four OCIs and the oil stayed relatively brownish until about 2k, when it started to darken. A few weeks ago I changed to Pennzoil Ultra Platinum and the oil is now dark after about 1k. I don't know exactly why the oil darkened so quickly after switching brands, but I have seen it on a few occasions on several cars.
 
Yep, shorten to 3K on this OCI, is a good idea. The lady may have run her OCIs a little-long. May take a couple OCIs to get amber color back at 1.5K. That's what I always shoot for..... clear-golden at time of oil change and amber at 1.5K

My oil-coloring ritual is going to be difficult with my latest Hyundai 2.4 GDI..... known for carbon. But so far - so good at 10K on the odometer.
 
I am thinking of picking up Valvoline maxlife synthetic for the next OCI and seeing if there is a change in the color. Also gonna grab a wix xp filter too. I have been using fram xg3600 the last three OCI.
 
I had this when I first got my wifes 07 Sienna with 25K miles on it. It was rental and they must have use conventional and ran it long. The first few OCIs were pennzoil ultra which is know for cleaning power. Turned black immediately. next OCI, same oil and it took a little longer. by the 4rth or 5th OCI is was looking good at the end of the run. from then to 150K miles when I sold it I never had a problem with oil turning dark early in an OCI.
 
Originally Posted by Triple_Se7en
Yep, shorten to 3K on this OCI, is a good idea. The lady may have run her OCIs a little-long. May take a couple OCIs to get amber color back at 1.5K. That's what I always shoot for..... clear-golden at time of oil change and amber at 1.5K

My oil-coloring ritual is going to be difficult with my latest Hyundai 2.4 GDI..... known for carbon. But so far - so good at 10K on the odometer.


Yeah I'm at 2800ish on this OCI currently and I have been monitoring the darkness in the oil since about 700 miles into this OCI.
 
Note that some ashless dispersants turn dark from UV exposure (from combustion events) making the oil appear black when it actually isn't. Whether that's happening here, I'm not sure.
 
Originally Posted by RDY4WAR
Note that some ashless dispersants turn dark from UV exposure (from combustion events) making the oil appear black when it actually isn't. Whether that's happening here, I'm not sure.


That would be interesting to test. A few ounces and a black light overnight.
 
Related puzzle:
My Prius turns synthetic oil (of every brand I've used, so far) dark much more slowly than every other engine I've known turned conventional oil dark. Is that because it's synthetic, or because less soot is formed in this engine, or because carbon is formed but sticks to the rings and pistons? As seen on the dipstick, the oil never turns very dark, but goes from almost clear to goldish to medium brown by 8000 miles or so.
 
Oil goes dark when warmed, even if its never been in an engine. If you watch the ProjectFarm videos where he heats oil to measure evaporative loss you will see that oil in a glass container sitting ontop of an electric heater will turn from amber/golden to dark brown, just form an electric heat plate. You cant really trust the colour of the oil to tell you anthing, you need to send a sample for analysis.
If you remove the oil fill hose and shine a torch in there can you see and varnish or sludge? When you drain the oil does it come out as oil, or a lumpy chunky 'cottage cheese' kind of deal?
If access is ok you might want to drop the sump and look inside, would be a good oportunity to check that the pick-up is not obstructed while you're in there.
 
18 year old vehicle with 76K miles... oil turning dark quickly..

My vote would be improper ring seal.. causing more soot particles in the oil from the combustion process.

Perhaps improper break in..or just carbon on the rings due to short trips or lack of driving.


Before next oil change you could think about a combustion chamber cleaner, then a a few italian tuneups. Perhaps pull some plugs to see what the combustion process looks like.
 
I'd run a shorter OCI, and for the last 1,000 miles of that OCI I'd add a bottle of Rislone to it. No harm in doing so and if it does have some sludge or varnish in it the Rislone will do some cleaning.
 
Considering the low mileage of that engine vs. the age, it may have seen a lot of short trips. You have changed the oil chemistry and are giving the engine some nice long runs, so there is probably some cleaning going on. Nothing to worry about, just keep driving it.
 
Castrol EDGE synthetic 5W30 turned black early in a late model , well kept engine on me that ran conservative OCI's using PP 5W30 (so I know deposits were few) . I personally think it's a Castrol thing - but I don't use Castrol any more as I believe I have found better all around oils versus EDGE like Valvoline Advanced and Pennzoil Platinum (stash being created) .
 
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