I have a 1998 2.5 and for the past couple oil changes the oil has gotten black extremely quick. 2 changes ago I did an oil system cleaning and put in Mobil 1 5w30 for the first time. Between changes I did a fuel system cleaning which I though was the cause of the black oil due to excessive blow-by. I went about 1,500 miles on that oil before doing another oil system cleaning and Mobil 1 again. The oil got to the point of needing a change after 600-700 miles and I did another more potent fuel system cleaning after that and it didn't make the oil quality any worse so I ruled that out. I have about 1,200 miles on the oil now and would like to determine the cause of the blackness before changing it. I did a compression test and all the seals tested perfect so I doubt it is excessive blow-by. The engine doesn't use a drop of oil so I know everything inside the engine is tight. I changed the PCV valve already so that can't be the cause. My only thoughts are that it has to do with the EGR valve somehow which makes no sense to me really but I don't want to tule anything out, the engine was poorly maintained and the synthetic is still cleaning all the gunk out, or my lead foot is just too much for clean oil. Let me know what you guys think.

 

Just because oil is black doesn't mean its dirty and needs to be changed.

I'm not sure what you're expecting. Maybe its really really black with particulate in it?

Usually it would take some lab work to determine if oil is good or worn out. Color/appearance is not an indicator.

 

Well black oil does mean dirty though not necessarily that it's not doing its job. The oil being black is an indicator that something is not acting the way it is intended. I do oil changes for a living and a properly working oil system will not contaminate the oil to the point of blackness in 1,000 miles.

 

I'd go with what wackjum said and try doing a UOA with someplace like blackstone labs, the numbers you get back might be able to point you in the right direction

 

Well I admit I don't do oil changes for a living.

But I've had plenty of cars and I've worked on plenty more. And oil getting dark after 1,000 or so miles has happened on all of them as far as I can remember.

Are you saying like pitch black (like what comes out of a lawnmower)?

 

Well yeah I guess I wasn't clear enough. Sure it'll get dark after 1,000 miles but it's to the point where it looks like it has been in there for 5,000+ after only 1,000. It'll look like actual black on a white surface.

 

Since you've done compression tests and all that good stuff, and you say the car isn't burning oil, I would guess that the cooling system isn't working properly. Heat is what ages oil anyway. It might be the cleaning thing you said but after so much time you'd think it'd be all flushed out.

Maybe the thermostat is defective and giving a normal reading when the car is actually borderline overheating?

I dunno. I'm grasping. Your tests seem to have covered the usual suspects. Maybe the path to the filter is blocked or slowed.

 

5w30? I always thought it's best to use thicker oil on older cars. Say 10w30...20w50. It should last longer.

 

As far as I know the more the mileage the thicker the oil to use. Try using high mileage 20w-50.

 

I wouldnt go past 5w-30. Honda engines have very tight fitting parts.

 

Today's oil includes detergent. Its job is to pick up the carbon particles throughout the system and hold it until it is drained.

These carbon particles are too fine for the oil filter to filter, but it's okay for it to cycle through the system. Like I said above, it's doing exactly what it should do -- pick up the dirt and hold it. Obviously it will look dirty in the process.

Now when you are seeing sludge, that's when things are going bad.

But I wouldn't be worried about dirty oil after 1,000 miles. In fact, that's exactly what it's supposed to - get dirty.

 

If you guys are using something above 5W30 where you're going to be starting your car in the cold then you're not giving it the right protection. 10W30 might be okay for summer but 5W30 is still just fine. And like I said before I understand the oil will be dirty but it is abnormally dirty. I'm going to change it again here soon and hope that it's just my engine was really dirty.

 

10w30 will start find at < 0F...it may just take you a long time....

Btw, a synthetic 10w30 will flow better than a mineral 5w30 @ < 0F.

OEMs have tested in cold weather ( @ -40F) to assume worse-case senario and this was done with 10w30 back in the days, and is done w/ 5w30 nowdays. All mineral oil.

 

For the past two years I've been using 10w30 and 20w50 for all my oil changes. I don't go through a day without spirited driving and I'm yet to have a slight rough idle or any problem what so ever with my engine.

 

i recently got an engine swap.. ive been using rislone with my oil changes.. ive had 3 oild changes since and my oil was black.. no big deal.. if you consistently use cleaning systems in your oil. the oil will naturally be very dirty until your engine is spotless.. thats a good sign if your using that stuff it mean its removing all that crud in your oil from the engine!

 

that is the worst piece of advice ive ever seen. Its like 35.00 for oil, or 3000 for an engine in most cases. If its a question, it needs to be changed.

This is why engine builders build engines, and science nerds do lab experiments.

Sounds like sludge buildup.

 

try some amsoil engine flush. You run it at 2-2.5k RPM for 20 mins straight while it heats up and cleans anything out of your engine then you immediately drain the oil out when its still hot so all the sludge and buildup flows out with it. its worth a shot at under $20 for a bottle.

 

i use a half quart of atf in there sometimes haha. that shit is too expensive and its just a detergent anyhow. Then again, anything with sludge like that id just rebuild anyways, so its rare i do that jazz.

 

And... hopefully you wont start leaking like a pig when you remove the sludge...

That amsoil stuff is alright... but like Colt said, it's too pricey... -_-;

Chris Longhurst's Engine Oil Bible.

http://www.carbibles.com/engineoil_bible.html

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