Propane engines won't turn oil black. Just load the oil with moisture so everyone thinks it has a blown head gasket when it milkshakes the oil cap.
Do you think black oil is really a sign of cleaning?
- Thread starter Silver
- Start date
Propane engines won't turn oil black. Just load the oil with moisture so everyone thinks it has a blown head gasket when it milkshakes the oil cap.
Is your Altima the VQ35DE? My 2014 Pathfinder has the VQ35DE and it turns oil dark very quickly too.
There are two separate processes a work that can darken your oil quickly.
EITHER it is oxidation (via hot spots in the engine or if its just a weaker lubestock, of the currently fashionable thin kind) OR it is doing a great job putting deposits into suspension, i.e. cleaning.
Sometimes it is hard to tell which process is at work. You ask yourself
"is my oil getting dark because the engine is high mile and its pulling deposits out? or is it subject to oxidation by either hot spots in engine or blow by or just being a bit thin for this engine, or maybe its winter and you have more blowby, or u do a lot of short trips etc etc"
Conversely when your oil stays clean a long time (as it does with both my Nissans) I ask myself
"Is the oil very stable, or my Nissans are very tight w/ no blowby, or is the detergent pack simply not removing deposits well in this engine?"
I sometimes switch between Mobil 1 and Valvoline Synthetic High milage ( which i know to be high detergent and perhaps different different detergent than the M1) to check which of those factors are at play.
but even my Valvoline high milage stays clean a long time.
Conclusion: My engines are tight, and have minimal deposits despite being very high milage ( 166,000 for the VQ40de and 178,000 for the VK56de respectively) and the lubes I use are not overly oxidation challenged by the loads in these engines ( which makes sense big engines have big wear surfaces, to spread out the load, plus they are both NA so run cooler than turbo oil etc etc)
Being in Florida so I never get a truly cold start probably doesn't hurt either.
I remember in the 90s I owned a VW Passat with the 6 cylinder engine ( which I lived) and the oil got black very quickly.
but it was winter in minnesota.... (so lots of cold start blowby AND the VR6 motor was known for hot spottingon the oil, hence the Summer spec of 20w-50 and the winter spec of 15w-40 for this gasoline engine)
EITHER it is oxidation (via hot spots in the engine or if its just a weaker lubestock, of the currently fashionable thin kind) OR it is doing a great job putting deposits into suspension, i.e. cleaning.
Sometimes it is hard to tell which process is at work. You ask yourself
"is my oil getting dark because the engine is high mile and its pulling deposits out? or is it subject to oxidation by either hot spots in engine or blow by or just being a bit thin for this engine, or maybe its winter and you have more blowby, or u do a lot of short trips etc etc"
Conversely when your oil stays clean a long time (as it does with both my Nissans) I ask myself
"Is the oil very stable, or my Nissans are very tight w/ no blowby, or is the detergent pack simply not removing deposits well in this engine?"
I sometimes switch between Mobil 1 and Valvoline Synthetic High milage ( which i know to be high detergent and perhaps different different detergent than the M1) to check which of those factors are at play.
but even my Valvoline high milage stays clean a long time.
Conclusion: My engines are tight, and have minimal deposits despite being very high milage ( 166,000 for the VQ40de and 178,000 for the VK56de respectively) and the lubes I use are not overly oxidation challenged by the loads in these engines ( which makes sense big engines have big wear surfaces, to spread out the load, plus they are both NA so run cooler than turbo oil etc etc)
Being in Florida so I never get a truly cold start probably doesn't hurt either.
I remember in the 90s I owned a VW Passat with the 6 cylinder engine ( which I lived) and the oil got black very quickly.
but it was winter in minnesota.... (so lots of cold start blowby AND the VR6 motor was known for hot spottingon the oil, hence the Summer spec of 20w-50 and the winter spec of 15w-40 for this gasoline engine)
My 93 Corvette has a rebuilt 396LT1. Low tension oil rings. Ported heads, manifold and larger injectors. Other than that, a simple catch can with a coalescing filter in line with PCV .
But, I have about 20000 miles on this, and have used mostly Mobil 1. Its always black at 5000 miles when I change the Filter. I have to add oil every 750 miles due to rings.
But one thing never discussed is the stuff they use to coat bearings, which is usually moly, and dark grey. How long does it take for an oil/filter system to get rid of that?
Maybe a Oil Analysis in its future.
On the flip side, my 02 Corollas oil never really changed color, even one time after 9000 miles. Mobil 1 too.
But, I have about 20000 miles on this, and have used mostly Mobil 1. Its always black at 5000 miles when I change the Filter. I have to add oil every 750 miles due to rings.
But one thing never discussed is the stuff they use to coat bearings, which is usually moly, and dark grey. How long does it take for an oil/filter system to get rid of that?
Maybe a Oil Analysis in its future.
On the flip side, my 02 Corollas oil never really changed color, even one time after 9000 miles. Mobil 1 too.
I agree, the black color is one of the sign the oil has been oxidized due to high temperature exposure. I have noticed my old Toyota with OHV low power relax engine always keep the oil clean for 10k kms, but the newer engine with VVTi will make the same oil black in 5k kms.
i have lpg (which is making way less soot). what i found:
1- lowsaps stealership 0w30 darkens faster than a normal fullsaps.
2- adding organotungstate does in both cases delay darkening. which makes sense because it is not only aw, but also antioxidant.
imho darkening can be because oil self degradation.
my 2017 car, short oci , i dont expect dirt inside. darkening should not come from that.
https://patents.justia.com/patent/7858565
https://www.vanderbiltworldwide.com...documents/technical/TDS_VANLUBE_W-324_Web.pdf
I have found the low saps oil to degrade quicker than full saps aswell. Darkening isn't of concern other than an early symptom, but varnishing is.
Full saps synthetic for me, please.
Full saps synthetic for me, please.
Similar threads
