Agggh! My Prius burning oil, what to do now?

agreed. i expect the gen III to do even better with synthetic.

 

Can you explain the logic here? Is it that the consumption wouldn't be as noticeable? Or, is it that by allowing the oil to drop you are increasing wear on the engine and causing oil consumption to increase.

 

When your oil quantity/pressure drops below a certain level, the rate of wear and oil consumption increases. That is why there are marks on the dip stick...to check and "maintain" your oil level.

 

When I went to the New Owners Night at our dealership, the service manager shepherded us through the service bays, and said "our goal is to make it so you never have to pop the hood". I felt like some kinda plant, hehe.

 

There have been many theories put out on the excessive oil burning. Oh, wait, it's not "excessive", it's "Toyota normal".

I think it may have something to do with the 0W20 weight oil. Too thin, and the rings may not be getting enough lubrication. I also think the thin oil may be responsible for the EGR plugging.

Anything for mileage!

 

You mean like removing the spare, P&G, slowing up traffic flow, ect...

 

I've contemplated that theory too, and it's as good as any of the other common theories (something to do with frequent starting, or hard carbon deposits clogging the oil ring, or ... ), at least until someone can prove it incorrect. I may try 5W-30, considering my car never has to start in extreme cold temperatures anyway. Of the three cars I've known well that went well over 300K without much increase in oil consumption, two used mostly conventional 10W-40 and the other one synthetic 5W-30.

 

On my next oil change I will skip the Toyota oil and go for something better most engine dont need but I really think that engine could benefit from a better oil will also flush my trans and use there ATF

 

interested in how the atf works for you /
keep us posted /

BION
StarCaller

 

I doubt Toyota 0W-20 is somehow causing oil consumption. Also I'd caution against putting anything besides Toyota ATF-WS in the transaxle.

 

Mendel the only protection agains friction between cylinder wall and ring is oil remove it and it will fail in second put better and you have very good chance it will last longer as for ATS did not do major research but as much as I know it is Toyota approved and pretty sure supperior

 

As per amzoil site
AMSOIL Signature Series Fuel-Efficient Synthetic Automatic Transmission Fluid


Signature Series Fuel-Efficient Synthetic Automatic Transmission Fluid
A fuel efficient automatic transmission fluid recommended for GM, Ford and Toyota transmissions where lighter viscosity oil is required. Provides the same excellent protection and performance as AMSOIL ATF. Recommended for vehicles requiring GM DEXRON® VI, Ford MERCON® LV and SP, Honda DW-1, Nissan Matic-S and Toyota WS fluid specifications.

Transmissions in commercial vehicles, SUVs, trucks and vans – particularly those used for hauling or towing – are subjected to severe-service operation and increased heat. Elevated temperatures cause fluids to break down, allowing damaging metal-to-metal contact and the formation of sludge and deposits. The problem is worse in modern transmissions with more gears, clutch packs and narrow oil passages that require clean, high-quality fluid to achieve maximum performance and life.

AMSOIL Signature Series Synthetic Automatic Transmission Fluid is specifically formulated to withstand the rigors of heavy towing, elevated temperatures and challenging terrain. It remains fluid in sub-zero temperatures and provides reserve protection during heavy use and even abuse.

Proven in 100,000-mile, Severe-Service Taxi Fleet Field Trial
To demonstrate its effectiveness in severe service, Signature Series Multi-Vehicle Synthetic ATF was installed in vehicles owned by a Las Vegas cab company. The vehicles routinely encountered demanding stop-and-go driving loaded with passengers and cargo, while the desert environment presented extremely hot ambient temperatures, placing enormous strain on the fluid. Following 100,000 miles, a transmission was selected for analysis. The Aluminum Beaker Oxidation Test (ABOT) is one industry-accepted method used to determine a transmission fluid's oxidation resistance, which is a good indicator of its service life. Testing by an independent, third-party lab reveals that after 100,000 miles in severe service, Signature Series Multi-Vehicle Synthetic ATF resisted oxidation longer than required for new fluid to meet the Chrysler ATF+4 specification (see graph). Internal components, including the valve body and clutch plates (pictured), were virtually free of damaging sludge, deposits and wear, confirming the lubricant’s high level of protection for severe-service applications.


Protects Against Thermal Breakdown
Signature Series Synthetic ATF is formulated with high concentrations of antioxidants, making it naturally heat resistant. As a result, it provides outstanding protection against sludge and varnish deposits that clog narrow oil passages and contribute to clutch glazing. After 100,000 miles in severe service, fluid analysis revealed Signature Series Multi-Vehicle Synthetic ATF contained 41 percent of its original oxidation inhibitors, proving its long-lasting resistance to thermal breakdown.

Outstanding Wear Protection
Varying speeds and loads causes torque multiplication and extreme stress on gears and bearings. AMSOIL formulated Signature Series Synthetic ATF with high film strength and premium anti-wear/extreme-pressure additives to help prevent wear during severe service. In the industry-standard FZG Gear Wear Test, Signature Series Multi-Vehicle Synthetic ATF that had been used for 100,000 severe-service miles achieved a “Pass” at stage 12 – the highest stage. The results exceeded the Ford MERCON V and Chrysler ATF+4 specifications for new fluid, demonstrating the lubricant's long-lasting wear protection.

Cold-Temperature Fluidity
Cold, thick automatic transmission fluid lengthens shift times and reduces fuel economy. Signature Series Synthetic ATF is wax-free and delivers extraordinary cold-flow properties (< -60°F pour point). It helps improve shift response, energy efficiency and warm-up times.

Friction Durability
Today’s transmissions are smaller and must withstand higher horsepower and torque while delivering smoother shifts, all with longer fluid life recommendations. AMSOIL Signature Series Synthetic ATF is formulated with friction modifier additives that deliver outstanding clutch-holding capacity (static friction), torque-transfer ability (dynamic friction) and anti-shudder properties (slipping torque-converter clutches). Analysis reveals that after 100,000 miles in severe service, Signature Series Multi-Vehicle Synthetic ATF provides nearly identical friction properties as new fluid for smooth, reliable shifts.

Applications
AMSOIL Signature Series Fuel-Efficient Synthetic ATF is recommended for transmissions and other applications that require any of the following specifications:

AISIN-WARNER AW-1; BMW 83 22 0 142 516, 83 22 2 152 426; CHRYSLER MOPAR® 68157995A, SP-IV; DSIH 6p805; FORD MERCON® LV, SP; GM DEXRON® VI; HONDA DW-1®; HYUNDAI/KIA SP-IV, SPH-IV, SP-IV-RR, NWS-9638, SP4-M; JASO 1A-LV; JWS 3324; MERCEDES BENZ 236.12, 236.14, 236.15, 236.41; MITSUBISHI SP-IV, ATF J3, ATF-PA; NISSAN Matic-S, Matic-W; SAAB 93 165 147; SHELL M-1375.4, M-1375.5, M-1375.6, M-L 12108; TOYOTA WS; VOLVO 31256774; VW/Audi G 055 005, G 055 162, G 060 162, G 052 540; ZF S671 090 255

AMSOIL Signature Series Fuel-Efficient Synthetic ATF is backward compatible and replaces DEXRON III fluids in older GM automatic transmissions. (DEXRON VI specification supersedes the obsolete DEXRON III in GM vehicles.)

SERVICE LIFE
Normal Service: Follow the vehicle manufacturer's normal-service drain interval.

Severe Service: Double the vehicle manufacturer's severe-service drain interval.

Change at the vehicle manufacturer's recommended drain interval outside U.S. and Canada.

 

If you look in the owner's manual you'll see a strong caution against using anything but Toyota ATF-WS. The Prius transaxle is a unique component, different than any typical automatic transmission. Also, we're pretty much completely off topic.

 

I'll add my agreement ONLY because the Prius transaxle is part electric motor, and the ATF fluid has to have special properties to properly work with it. Supposedly, that's why you need to "drain and fill" it...not because the ATF fluid is "bad" but those properties deteriorate after a while, and eventually they just aren't doing what needs to be done...even though the "lubrication" quality is still present.

I do use AMSOIL in all my vehicles (even the Prius) for oil.

My 2 cents (please correct if I'm wrong), but I think the biggest culprit for oil consumption is lack of use of the ICE. I've seen old vehicles blow smoke (burn oil) because all they ever got was stop-and-go driving for years. Put them on the highway for a couple of months and they stop smoking. I think occasional trips up and down the highway (where the ICE always stays on) once a month is a good way to ensure your piston rings (or other stuff) isn't getting odd wear from inconsistent use. The ICE really works best (longevity-wise) when it gets used long enough to reach and remain at proper operating temperatures. Stop-and-go driving kills standard motors a lot faster than tons of highway miles do.

 

My reasoning is simple. The thinner oil gets by the oil ring easier, so more is available to burn. This burning or incomplete burning adds "stuff" to the EGR system that clogs it. It also clogs the oil ring, causing even more oil to be left behind to burn. Lubrication still works just fine. You just loose more oil than you expect, and the EGR system fails once it is plugged.

I wonder if we could test this with "cold area" operation vs "hot area" operation reports of oil consumption. Reasoning being that in "cold areas" the engine temp. averages at a lower value. I know Pearl S rarely sees coolant temps close to the thermostat opening value in winter. Even with the lower grill completely blocked. Burr!

 

there is plenty of evidence for the hard carbon deposits clogging the oil ring and not much for the others.

 

My experience with motorcycle, car, and small aircraft ICEs in the 60s-80s would also suggest wear of the cylinder wall itself as a contributory cause, and I think I had some occasions where the oil ring was kind of "stuck" by accumulated carbon, especially on 2-stroke engines, and other occasions where the oil ring was simply worn. (Valve stem seals was a completely different source of oil consumption, which I usually tried to determine with a compression check and comparing full-throttle smoke with high-speed throttle-off smoke levels.)
Has anyone disassembled a worn Prius engine to measure these factors?
We used to re-bore the cylinders and install oversize Pistons and rings, but I do not think that is possible with alloy-block, surface-treated cylinder walls, which I am assuming the Prius engine uses.

 

yes, but you have to remember that when rings get stuck, they lose elasticity and abnormal ring/cylinder wear quickly follows making oil consumption irreversible. the window for fixing stuck rings is fairly short.

prius engine still uses iron cylinder liners, but engine rebuilt is too expensive these days to be routine (in this country).

 

i wonder if the o/p is monitoring his dipstick.

 

I've been using AMSOIL 0W-20 for the past two years since I purchased the car with the 40K miles on the clock. Doesn't burn any oil between the 15K mile changes.