Discussion in 'Gen II Prius Technical Discussion' started by epoch_time, Mar 26, 2012.
I probably only needed to siphone 4 ounces during the 4000 to 8500 mile interval.. But I've become obcessed siphoning 4ounce
as each time I do it there is preformance gain and mpg gain along with extra quiet engine...
I havent been doing the siphoning as a result of changing oil level...except the first time at 4000-4500 miles.
I haven't noticed the level changing over the last 4000 to 8500 miles although I suspect about and ounce gain in oil each 1000 miles.
That has been the rate of fuel dilution.....
The smell of the oil is mostly what is driving these frequent siphon's not any level change...and the preformance gains...
It seems that the smallest unmeasureable amount of fuel in oil causes loss of lubrication and preformance...and is only detectable by smell....
The minimum amount of surface oil that I can siphon before loosing siphone is between 2 to 4 ounces...after each siphon
I'm haunted by the fact that I possibly didn't get out all the fuel dilution (indicated by smell only , not oil level)
When the siphon stops I feel that I have gotten the last drop of surface oil but the real question is how deep is the fuel dilution...
The fuel dilution is more shallow in depth after longer periods of parked unused prius...
I have definately gotten out of control with this because I only needed to siphone 8 oz over 8500 miles total.. and this should be your guidelines for restoring your extended oil to near new condition. if you want to run moblie 1 5-30 oil 10-15k miles...you must remove fuel diluted oil or just replace oil at no more than 5k intervals.....
I aslo feel something sounds wrong. Would think gaso and lube oil should be 100% soluble so they would not separate on standing. The only time you see oil separating is if a wax layer forms, that will sink. But there is no wax in gaso or lube oil. It is possible for fine particles to settle with time, giving a more clear appearance to the upper layer. Water if present or antifreeze ought to settle to bottom. If water is present it is probably emulsified with solids and should sink with time. I am trying to imagine if there is some way for ethanol break out and float to the surafce but I do not think so. If there is water the ethanol would combine with it and sink.
Agreed! To me, all the work that the OP's doing is based on guesswork and gut feelings rather than any actual data/hard science. I've never heard of anyone else siphoning off oil out of their Prius. I doubt the 12 volt bus' voltage has anything to do w/more or less complete combustion of fuel either.
The times that I've checked my oil, I've also noticed a strong gasoline smell in my oil.
FWIW, I did have my Prius' oil analyzed once by Blackstone. They said "We aren't sure, but we were under the impression that a Prius' gasoline engine does not engage when it is started and moved. If so, moving the car would have no affect on the 3.3% fuel dilution found in this sample. This amount of excess fuel is cautionary, and may show a fuel system problem developing. The fuel was likely to blame for the low viscosity. Wear metals are low, so the fuel has probably not affected the engine mechanically. The TBN was 3.5, showing plenty of active additive remaining in the oil. A TBN is low at 1.0. Resample to watch fuel."
I haven't bothered to but maybe I should...
Personally, based on skimming the OP's posts, I think these "problems" are in his head and he's making work for himself w/o any data.
Thanks for sharing the data. At what mileage was the analysis done? Do you have lots of stop and go low speed driving or mostly highway high speed driving? My used oil was once detected 0.5% fuel but I never smell gasoline in the oil.
...good data. That viscosity loss is why I stick with the recommended 5W-30 (or 0W-30) weight oil for Gen-II.
In reality that's what the OP is saying, he feels he is losing viscosity, and he feels siphoning off may help the maintain visc.
PS-I actually have the 15k Mobil-1 5W-30 Extended Performance in the Prius now. I will see if I can send small samples to Blackstone. Put it in a few weeks ago.
This is not meant as a criticism but I feel the OP is treating the symptoms of the problem rather than the cause, and as such is storing up even greater problems. There is no way that the fuel and oil will separate in an engine "as stated by wjtracy" that will mix the two better than any blender, and any attempts to reduce the level is allowing even greater levels of dilution.
Hey folks the Blackstone labs website is a hoot if you have not seen it - check out the FAQ's.
You can pay $30 for a sample pump that would also serve nicely as a fix for the "putting too much lube oil" in the Prius problem. Note the normal sample kit is free so you might as well get one. Of course they assume you will return the sample for $25 lube oil analysis fee.
I am a 30 year user of Mobil 1 and can tell you the fellow in that link is a bit confused about Mobil 1 oil VS Mobil super sybthetic. There is no such thing as Mobil 1 super synthetic.
The Super synthetic is a hydrocracked base oil, but does NOT carry the Mobil 1 name.
Mobil Super synthetic is avalible locally about 30% cheaper than Mobil's true synthetic, Mobil 1.
Within the last year, Mobil totally revamped their motor oil lines.
Mobil does now make a cheaper hydrocracked synthetic oil, BUT, that is Mobil SUPER SYNTHETIC, NOT mobil 1.
Mobil 1 is still the same PAO based pure synthetic it has always been, The original mobil 1 POA synthetic good for 7500 -10, 000 miles, or the extended range POA based synthetic good for 15,000 miles.
If your having thinning problems with either of the Mobil 1 POA based Synthetics, I suspect you are getting fuel dilution due to an engine fuel system problem, or a lot of short trip cold running.
Mobil USA | Car Engine Oils | Mobil Super Synthetic Engine Oils
At the time it was done, it was after only 2931 miles but I believe 7-8 months (I'd have to find my receipts to be sure), not shorter than 6 months.
At the time, it was mostly low speed, short city driving w/short trips. The sample was taken in November 2010, when I was in WA state. It's not exactly that warm there during that time either (many days of highs in the 40s and 50s?). I think it snowed close to the sample date.
I'm in CA now and my current drives are a total mix and unpredictable. But most tend to be city and expressway (45-50 mph) driving and not very long (<20 mins a leg). But, sometimes there were 25-40 min trips, w/some highway in there. I do recall smelling fuel in my oil here in CA.
When I had my 350Z oil analysis done by them, it had 2.0% fuel dilution. The drives when I was up there were also WAY short. I sold my Z before I moved back to CA. :/
Maybe once I start working again (which almost certainly means I'll have longer drives) I should get a UOA done by Blackstone again...
I'm now on my second oil change since all of my oil siphoning frenzy began.
My last oci had about 6k miles in which I siphoned four different times a total of about 16 oz (4oz per siphone) adding 16 oz new
mobile-1 5W30 extended...
My conclusion after all this;
You can burn off fuel accumulation (in oil) by simply drving prius 80-100 miles of nonstop hiway driving every 1000 miles of mixed
city & hiway miles..And not bother siphoning any oil... That was the good news....
Now the bad news.. after 6k miles with some fresh make up oil added because of siphoning..
The mobile-1 5w-30 extended performance seems spent and is total used up for my intentions...
I believe there two camps (people types). the first type (me) uses mobile-1 full synthetic to minimize engine wear..
The second camp wants to minimizes oil and filter changes.
I will be changing my mobile1 synthetic at around 4.5 k miles and probably not be doing anymore fuel diluted oil siphones.
The people running mobile-1 5w-30 out to 10k miles will be loosing superior lubrication at around 4 or 5k miles and only receiving
dinosaur quality lubrication after that or maybe less...
Hopes this clears up everything.
There is nothing wrong with my injectors..
Never been any warning light and I've never got less than 54 miles per gallon car is perfect..
Engine sounds like the day I bought it provided oil has under 4k miles!
Thanks for all the posts, wisdom, and expertise..
Injectors that leak will not necessarily cause a warning light so how do you know there good?
Did you remove them and have them tested?
I've smelled fuel in genIII oil , prius c oil , my genII and all have gas smell,, many oil analysis of prius-chat owners show 2.5 - 5 % fuel in oil..
All the prius ive smelled were brand new..
My prius on longer has fuel smell as long as I do extended drives once every 1000 miles..
And your prius oil wont smell of fuel if you do extended drive once everry 1000 miles...
I've had oil that smelled like fuel. I was siphoning out oil at 4oz per 1000 miles as contaminated oil/fuel seemed to float after days of prius sitting.
After noticing no charge arrows on initial engine startup while prius is in park. I decided a reboot of all prius ecu's was nessary.. Bytheway scanguage showed about 11 amps charge after engine start while in park but
multifunction display showed no arrows at all.. (suspicious).
So I drove to a nice level place as fuel tank ecu requires level while calibrating fuel ecu...
I put car in neutral and pushed forward and backward about a foot or two and with equal force to move car
forward and backward. I belive this proves ground and car is level.
I then unpluged aux 12 volt battery for about 2 to 3 minutes ( there are two wires that plug into positive side
battery terminal ) .
With everything off.the small size wire (voltage sense wire) should be unpluged first.
Then the large diameter wire should be disconnected second..
When reconnecting the large wire should be connected first and the small wire secondly.
With the 12v batt disconnected it did turn on the parking lights to drain off any remaining charge from system.
After reconnecting 12v aux batt. and putting car back together.
I drove off noticing an immediate difference. Prius now accelerates wonderfully with hardly any gas peddle depression.
Monitoring short term fuel trim with scanguage is at +6 for the first quarter mile, +5 the next quarte rmile
and fell to zero after about 1.5 miles... Before short term fuel trim was mostly -2,-3,-4 hardly ever seen positive short term fuel trim numbers if ever !
After about 20 miles city driving and now getting 67 mpg instead of 54 mpg car seems extremly smooth and responsive.. I smelled the oil (after 20 miles) not a trace of fuel.!
Its now been three days since ecu's reboot and no trace of fuel smell in oil..
I notice negative numbers indicate fuel added (rich) positive numbers fuel mixture lean as seen on scan guage.
Long term fuel trim is at + 4 and didn't seem to change after reboot.
When accelerating short term fuel shows + rich fuel mixture. When cruzing speed is established SFT goes to 0
When climbing hill SFT goes negative (rich). while going down hill SFT goes Positive (lean). There are exceptions to this.. but on the average while cruzing sft is 0 and load fuel gets added.
i replaced 12volt batt about 2.5 -- 3 years ago and have not had any dead battery issues after replacing it.
Battery checks good under load and still seems new..
I lost programmed beep setting (seat belts etc) lost 3 segments of fuel gauge reading, power window settings, trip a and b got zeroed as well as ave miles and accumulated miles on multifunction display zeroed after reboot, but did not loose radio presets. (maybe I should have left battery disconnected longer ?
I had about 8 segment on fuel guage before reboot and only 6 bars after but I got slightly over 100 miles on that
sixth segment as opposed to getting about 27 miles on the six segment..
Fuel guage seem back to normal after about 150 miles of driving.
Perhaps the prius should be rebooted/reinitialized once in a while and deffinately after dead battery, jump starts, or odd behaveure...
iTS been 11 days now since I reinitialized/rebooted ecu's by removing 12 volt power and all is well, Prius is accelerating wonderful, and no
smell of fuel in oil... the fuel trim was screwed up for the past 15 months or longer...
Interesting story and thanks for a followup. The couple of cars I had that were gas guzzlers (no chance of getting EPA numbers) fuel trims were negative and one tested with 5% fuel in oil. The only problem was ECU reset didn't help in those. Believe me, I tried hard. You are lucky you fixed it by a simple reset. Next time I buy a car, I'm taking an OBD2 scanner with me.
I now have 4 k on the last oil change and my oil still is yellow in color..
Oil before with this milage would have been dark brown
After disconnecting 12 battery to reboot/reset ecu's my short and long term fuel trims look great, oil no longer smells like gasoline.
And amazingly the day after ecu power down/ reset / reboot.. the oilactually looked cleaner..
Separate names with a comma.