Black engine oil after every 3K mile oil change..

[DK327]

Hey all, so I just hit 240K miles and decided it was time for an oil/filter change. Last time I did this was at 237K miles. After it drained out exactly 5qts and I removed the old filter (Mobil1 extended performance) I looked and the oil was dark and smelled burnt. I put new oil in (5.5qts Mobil Super High Mileage) and the new filter (Toyota OEM) and can tell the vehicle is running much smoother. I change my oil every 3K miles (around every 6 months) like clockwork and it's always the same. Wondering if I should switch to another brand? I don't want to put full synthetic in there but wouldn't mid trying another brand, open to suggestions.

 

[jgue467]

Well it's getting carbonized, somewhat normal, to what degree is the trickier part. You may want to have an oil sample examined for the details.

Do you run an occasional seafoam or startron fuel treatment? seafoam can also be placed into the oil during last couple hundred miles before next change to help decarbonize lower engine.

Don't fear full synthetic, it is better oil at both lubrication and cleansing. I have used it for over 140,000 miles with zero issues, so have many other on here. Stories of it starting oil leaks are just a coincidence, these engines leak oil all the time for a variety of reasons.

Overall just keep changing the oil/filter as you have been. Luck. :cowboy:

 

[hour]

Mine comes out dark and smelling like used oil, ~3k intervals / min 3x a year, ~260k miles. Mine isn't my primary car and it sounds like yours may not be either if you change every 3k / ~6 months. If your oil isn't getting fully warmed up / you're doing short trips, off roading, doing things in the summer heat, towing, hauling, etc. maybe consider shorter intervals?

I just bought 5W30 high mileage full synthetic Pennzoil from Walmart for like $22 with a $10 or $12 rebate (I promptly lost the receipt, f). I've been running Valvoline max life syn blend for years in it without any complaints but figure full synthetic will be better overall for how I drive, and then the periods of time it sits with little use in the cooler months. Maybe try switching to either of these, the max life is usually $16-17/5qt jug

 

[LittleCaesar]

How long have you owned it? It could be from previous lack of changing oil and now that you are changing it more frequently, the oil is doing its job. I'd be curious to know what it looks like under the valve covers.

Mobil Super HM is a great oil. Use it with no worries as long as you aren't burning any oil.

I used Mobil 1 EP in my 4runner back in 2008/09. Probably the least liked oil by the 5vz to date.

 

[catrains]

black smelly oil would indicate poor combustion. so it is most likely a spark problem or the fuel system is dumping too much fuel into the engine.

I would check for spark problems like plug/wires/coils etc. then check the O2 sensors upstream that they are switching properly , fuel trims should be close to zero if they are high then that is the problem.

dirty injectors leaking at those miles is possible fuel trims should show this at idle.

my 2000 has 170K miles on it I go 10K miles on mobil synthetic and it is not black but a dark brown . fuel trims are around zero.

 

[etc.]

You'd be best off searching BITOG and sending the oil off for analysis.

What oil did you use during your last oil change? I'm not sure about the Super but the synthetic version of the high mileage is considered one of the best oils for cleaning so a dirty oil is to be expected.

Why use the EP filter if you're changing the oil so often?

 

[Mudeprived]

Well it's getting carbonized, somewhat normal, to what degree is the trickier part. You may want to have an oil sample examined for the details.

Do you run an occasional seafoam or startron fuel treatment? seafoam can also be placed into the oil during last couple hundred miles before next change to help decarbonize lower engine.

Don't fear full synthetic, it is better oil at both lubrication and cleansing. I have used it for over 140,000 miles with zero issues, so have many other on here. Stories of it starting oil leaks are just a coincidence, these engines leak oil all the time for a variety of reasons.

Overall just keep changing the oil/filter as you have been. Luck. :cowboy:

Synthetic does start oil leaks. I can prove it with both my vehicles. :laugh:

 

[a216vcti]

black smelly oil would indicate poor combustion. so it is most likely a spark problem or the fuel system is dumping too much fuel into the engine.

I would check for spark problems like plug/wires/coils etc. then check the O2 sensors upstream that they are switching properly , fuel trims should be close to zero if they are high then that is the problem.

dirty injectors leaking at those miles is possible fuel trims should show this at idle.

my 2000 has 170K miles on it I go 10K miles on mobil synthetic and it is not black but a dark brown . fuel trims are around zero.

What do you use to analyze fuel trims?

 

[Kotrin]

How long have you owned it? It could be from previous lack of changing oil and now that you are changing it more frequently, the oil is doing its job. I'd be curious to know what it looks like under the valve covers.

Mobil Super HM is a great oil. Use it with no worries as long as you aren't burning any oil.

I used Mobil 1 EP in my 4runner back in 2008/09. Probably the least liked oil by the 5vz to date.

Why do you say that? Because people going the 15k mileage between? I switched to a similar just to see if it makes a difference for a couple of changes. I've researched that, like everything, you can get both sides of the story.

 

[LittleCaesar]

Why do you say that? Because people going the 15k mileage between? I switched to a similar just to see if it makes a difference for a couple of changes. I've researched that, like everything, you can get both sides of the story.

My 5vz, in using the Mobil 1 EP, was noisy and just seemed less peppy. Plus I swear it helped start the valve cover leak back in 09. I have used it in a Mazda 6 with great results though.

 

[AntleredRuin]

Synthetic does start oil leaks. I can prove it with both my vehicles. :laugh:

Incorrect. Synthetic is simply a thinner oil with cleaning properties. It can clean a sludge build-up 'plug' and expose a hole in the seal that was already there, but it will not be the original cause of the hole.
If you have sludge plugging holes in your seals, it's most likely plugging a lot of other areas in your engine as well.

 

[octanejunkie]

Do you run an occasional seafoam or startron fuel treatment? seafoam can also be placed into the oil during last couple hundred miles before next change to help decarbonize lower engine.

I would not run Seafoam in my oil for a couple hundred miles, it thins out the oil quite a bit. I run seafoam for about 30 mins in a warm engine on the way to get an oil change.

If you want to run something for hundreds of miles, top off your crank case a week or so before your next oil change with ATF. YMMV

 

[Kotrin]

My 5vz, in using the Mobil 1 EP, was noisy and just seemed less peppy. Plus I swear it helped start the valve cover leak back in 09. I have used it in a Mazda 6 with great results though.

That's hilarous because I just did Mobile Extened Performance (EP) and my slight ping went away oil looks good and all my normal leaks are still the same. I do know that everyone has a personal preference and sometimes things just work differently. I want to find just one and stick with it and thought I would give this a try. I will still change my oil every 3-5k miles (or right after my Ouray trip in September). If all goes well and my Alvord Desert Trip in June shows no problems i'll keep using this oil. The lack of the pinging made me smile as I was just frustrated with it (but I knew it was nothing to really rush to tear apart at this time). But thank you for your opinion, what do you use? I saw you recommend high mileage (glad to use that though i'm only at 130k).

 

[Kotrin]

I've always been told Seafoam in the crank = you replacing things EARLIER!!(aka no no). Though in the fuel is fine. I haven't ran any since I purchased it, but I try my best to just do the requirements and personal experiences.

 

[T4R2014]

Change the oil and move on with life.

 

[jgue467]

I would not run Seafoam in my oil for a couple hundred miles, it thins out the oil quite a bit. I run seafoam for about 30 mins in a warm engine on the way to get an oil change.

If you want to run something for hundreds of miles, top off your crank case a week or so before your next oil change with ATF. YMMV

It's what the instructions on the seafoam can say to do (one ounce per quart of motor oil) last 300 hundred miles but I only do 200, I've done it on this runner over 140,000 miles every 5k with zero issues - purrs like a kitten. But hey I can see how some think it's scary (so don't do it)! I just put it out there as a way for OP to clean up engine faster than just oil changes but to each their own. :cowboy:

 

[DK327]

How long have you owned it? It could be from previous lack of changing oil and now that you are changing it more frequently, the oil is doing its job. I'd be curious to know what it looks like under the valve covers.

Mobil Super HM is a great oil. Use it with no worries as long as you aren't burning any oil.

I used Mobil 1 EP in my 4runner back in 2008/09. Probably the least liked oil by the 5vz to date.

I've owned it since 230K miles, it came with no service history aside from a sticker on the engine stating Timing Belt was done at 165K miles. I've since done 3 oil changes including the most recent one and I've used same oil and new filter each time. I know I have a timing belt/water pump replacement coming up soon, as well as valve cover gasket job so I'll be able to tell more about the condition of the engine then. I might be burning some oil as I ended up dumping 5QT's during change and put back in 5.5QT's but no leaks so I'll continue using regular oil or synth blend at best.

 

[DK327]

It's what the instructions on the seafoam can say to do (one ounce per quart of motor oil) last 300 hundred miles but I only do 200, I've done it on this runner over 140,000 miles every 5k with zero issues - purrs like a kitten. But hey I can see how some think it's scary (so don't do it)! I just put it out there as a way for OP to clean up engine faster than just oil changes but to each their own. :cowboy:

I've done the seafoam in the gas tank but not in engine on this vehicle. I'll see to it around next oil change which will actually be sooner than later since in a couple of weeks I'm taking a long trip to SD and back.

 

[DK327]

Mine comes out dark and smelling like used oil, ~3k intervals / min 3x a year, ~260k miles. Mine isn't my primary car and it sounds like yours may not be either if you change every 3k / ~6 months. If your oil isn't getting fully warmed up / you're doing short trips, off roading, doing things in the summer heat, towing, hauling, etc. maybe consider shorter intervals?

It IS my primary vehicle but as you stated it might be due to constant short trips around town. I work less than 10 mins from home so by the time engine reaches 190F I'm already at work, this might take a toll on oil faster than a long trip I'd imagine... Good point!

 

[DK327]

black smelly oil would indicate poor combustion. so it is most likely a spark problem or the fuel system is dumping too much fuel into the engine.

I would check for spark problems like plug/wires/coils etc. then check the O2 sensors upstream that they are switching properly , fuel trims should be close to zero if they are high then that is the problem.

dirty injectors leaking at those miles is possible fuel trims should show this at idle.

my 2000 has 170K miles on it I go 10K miles on mobil synthetic and it is not black but a dark brown . fuel trims are around zero.

Thanks for the pointers, it's got new plugs and wires as well as new fuel filter, all OEM since 10K miles ago. I was actually thinking about using a reputable fuel injector cleaner and see if this helps but so far no codes or dash lights indicating any O2 sensor issues... Maybe I should have replaced the O2 sensors while getting the new exhaust put on last year but since no codes, I let it go... This might be a to-do item on my list in the future.