Oil Cleanliness

Just had mine changed at 35,000 miles, and it was in for 10,000 miles and while it was not as clean as the new oil, it was remarkably clean, considering the miles. It was cleaner after 10,000 miles than our Odyssey is after 3,000 miles on dino oil.

 

I also have used Mobil 1 synthetic oil in my rigs for going on 30 years now.
I usually changed at 10,000 miles, by that time the Mobil 1 had gone from baby oil clear to dark brown maple syrup.

My 2010 Prius was still on the 5000 mile schedule for the first change, where they installed Toyota synthetic oil and told me to run it 10,000 miles. At the 15,000 mile change, I was flat amazed that the oil was only starting to color very slightly and still on the full mark, it still looked new. That indicates to me that the ring seal in that little 1.8 engine is near perfect.

 

It's not the dirt in the oil you have to worry about. It's the water and fuel. -THAT'S- why you change the oil!

 

With a proper running modern engine, water and fuel never become a problem. Oil needs to be changed because of viscosity change or too low a TBN.

 

Water in the oil generally is not a problem if one drives the vehicle long enough for the engine to reach normal operating temperature. At normal engine/oil operating temperature, water in the oil will boil out or evaporate from the oil. However, making a lot of short trips where the engine (and oil) does not reach normal operating temperature results in residual moisture in the oil which can cause problems if the vehicle is not used regularly, or brought up to normal operating temperature on a regular basis.

Keith

 

Apparently a lot of forum members don't use a Scangauge. Pearl's engine doesn't reach "normal operating temperature" in the city unless driven for at least 30 to 45 minutes. In other words, hardly ever when I drive.

So I repeat. It's the water and fuel in the oil you have to worry about. Don't argue unless you have had an oil analysis done!

 

what is considered full operating temperature

My Prius likes to stay at 188 - 192 F at all times. Only occasionally does it go over.

 

That's full operating temperature although it can go higher under hard use/hot weather and still be acceptable.

What really counts for water in the oil though is oil temperature. AFAIK, we don't have an engine oil senser on our Prii. I hope someone will prove me wrong.

On a car without an oil cooler (like ours), the oil temperature lags coolant temperature by 15-30 minutes during warmup and will eventually get hotter than the coolant, but there are exceptions. You can't really tell without an oil temperature gauge.

 

I would check metal contaminants level (in ppm) and viscosity level of used oil.

 

I believe the full operating temperature on the 2010 is 195, as that is where mine will sit regardless of OAT when running with the cruise for long distances. I believe this is also the t-stat temp for many of today's cars.

 

Here is my oil analysis.

 

So you have 50,000 PPM of fuel and only 21 PPM of silicon. I would worry about the silicon but not about the other metals (they are soft and used in the bearings anyway, which is probably where they came from). Not sure what 0.20 of water means (%, PPM?). If % then it can be troublesome. The silicon could have come from the aluminum (it's part of the alloy) or from the casting residue.

But as I said, worry about the fuel (it dilutes the oil and can cause it to break down faster as can the water).

And I reiterate, that's why we actually change the oil. It would lubricate just fine for over 20,000 km but the contaminants cause the problems, and you can't filter out the fuel and water with an ordinary filter.

Do note that the "oil filter study", found on-line, has shown that oil filters plug after only a few thousand miles and the engine operates in "bypass" mode after that. I find some truth in that study as a filter manufacturer tried very hard to get it off-line.

Finally, do note that saying which has a lot of truth in it - "figures lie and liars figure". I'm not deliberately trying to state an untruth, but I certainly could be wrong.

 

The scangage in my Gen 2 Prius stays at 184 F the vast majority of the time.

 

The fuel is a problem.

High metal levels that show up in a regular oil analysis are in the less tha 3 micron size range. They are signs of a problem, not so much of a threat their selves. Bigger particles don't end up in the report unless you have a particle count done. You can have some really big stuff in your oil and it won't show up in a oil analysis unless it has been there long enough to cause the small micron stuff to show up.

High levels of sodium in the oil can be an indication of coolant leaking into the oil. Unusually high water levels are another indication. His aren't at the disaster level yet but could be an indication.

Coolant in the oil results in higher readings of other metals because the oil doesn't work very well with coolant in it. I don't know if his sodium levels and water levels are high enough to be the cause of his metal readings, but it's something to consider.

 

The oil analysis report I posted is from a watercraft with supercharged (17 psi max) 300 hp 1.5L 4-cyl engine that can propel the 1100 lbs vessel to accelerate 0-60 mph in less than 3 seconds. Such high performance forced induction engines are known to have high content of fuel in crankcase oil after some usage and frequent oil change is recommended. Unfortunately the company I used for the analysis can't come up with accurate number for more than 5% they say. I need to look for another oil lab company. Any recommendation?

 

No recommendations because I have never had to deal with that much fuel in oil.

What engine is that? Sounds like fun.

Is the sodium for salt water mist?

 

It's a supercharged jestki.



Routine oil analysis on high performance engines can save you big $$ if you catch the problem in the beginning by monitoring the lab result trend so that you don't end up with something like this.