Oil Burning

So if I was the guy making french fries at McDonald's, its okay to keep on adding oil since the oil in the fryer would always leave with the fries? Wouldn't the oil in the fryer be in some nasty mess if you kept this up for a few years - lots of bad oil, residue, not to mention the french fries you were making wouldn't be as tasty anymore..

 

Unfortunately that doesn't work that way. You would need a full drain to see the benefit of the fresh oil change -- adding one quart of fresh oil into four quarts of dirty oil doesn't make much change, especially considering the fact that most contaminants remain in the oil pan.

In addition your oil filter might get clogged and open the bypass valve in it and then you would end up with unfiltered oil circulating in the engine. OEM Toyota oil filters have very poor filtering efficiency and therefore are less likely to clog than top-quality, high-efficiency oil filters (such as Purolator PureOne) but this might still be a problem with high-mileage engines and long oil-change intervals.

 

I think the larger question should be:
If a Prius burns a quart of oil every 600 miles, would it still be a "low emissions vehicle"?
Mine has ingested no (measurable amount of) oil in its first 3,000 miles of life.
If my 09 Sierra ever starts to burn more than a quart of oil in 3,000 miles before it gets to the 200,000 mile mark---then this will immediately illuminate the "change owner" light.
I check my oil level every fill up. I've had 2 dozen vehicles of every stripe, and I've NEVER seen a "normal" (4-cycle) engine burn oil at a rate of one quart every 3,000 miles.
This has to be a typo. How can a vehicle that burns over half a quart of oil every fill-up ever pass emissions testing?

 

The answer is, as long as all the emissions components are functioning, yes, it will pass the California emissions tests even with 1 qt per 600 miles oil usage.

The limit of 1 qt per 600 miles oil usage is the standard criteria for engine repair due to excessive oil consumption and it has been out there since the dawn of time, not new or special to the Prius.

 

What I'm thinking you mean is that 1qt/600 miles is the "standard" dividing line between a marginally functioning motor, and one that has to be down-checked for maintenance.
Yeah, I get that.
I can see where this question might come up in a forum about 1930's Ford 3-window coupes...but really? In a Prius???

C'mon!

 

No you would change the oil at the normal time.
Say the fryer lost more oil than normal would you start changing the oil 2-3 times more often than you did, or would you keep adding oil, then change it at the normal time. Say Mcdonalds changes their oil every day, if a fryer was leaking and they had to start adding some oil it they wouldn't say it's loosing oil we need to start chaning the oil 3 times a day now. They would need to add oil to keep it full all day then change it once a day like they always have.

And to comment on Gokan "Unfortunately that doesn't work that way. You would need a full drain to see the benefit of the fresh oil change -- adding one quart of fresh oil into four quarts of dirty oil doesn't make much change, especially considering the fact that most contaminants remain in the oil pan"

But having to add oil will not make where you have to start changing the oil early. You would just change at the normal time. Adding fresh oil doesn't make more oil changes needed.

In my other post i was just commenting on the fact it wouldn't help to change the oil early at 2k or 3k or 5k if your car was loosing/burning oil. if you could/didn't want to fix the problem, you would want to keep adding new oil to keep it full then change at the normal time. no need to change early cause your adding fresh oil alot.

 

Are you saying the prius wouldn't warn me the oil is low or the oil pressure is low so i could pull off the road and shut it off before damage is done? All the the GM cars/trucks i have owned would warn me, a few of them would let me know if i was a quart low with a message saying" check engine oil level", and that would be before damage was done. and before the bashing starts i never had to add oil in them but did read my manuals.

 

Prius uses the same ICE technology as in other Toyotas. Gen II engine was virtually identical to the Yaris engine and the Gen III engine is virtually identical to the Corolla engine.

In most Toyota engines, you won't see excessive-oil-consumption problems until at least the engine becomes ten-years-old. Therefore, few Gen II or Gen III Priuses will have this problem but quite a few Gen I Priuses with excessive mileage might be having the problem.

 

Oil-pressure warning light comes on only when the oil pressure is very low. This low pressure is not sufficient to protect the engine under normal driving. If you see the low-oil-pressure light, pull over immediately and turn off the engine. Driving even one block will ruin your engine.

 

I said exactly what you are saying. But I was commenting that, with an older engine, oil deteriorates more rapidly and you would benefit from shorter oil-change intervals.

 

My 2 cents here.
I have a 2007 Prius. I have done nothing to it except change oil and filter every 5000 miles and a couple sets of new tires. I have 101,000 miles on it. Never had any measureable oil usage so I sort of gave up checking in between oil changes.

Except: Last time I changed the oil I was startled to see that I only got about 2 quarts out of it, indicating that the car burned 1.7 qts in 5000 miles. (I know because the waste only filled half a gallon milk jug that I use to take it to the recycling center.

Today - same thing, 5000 miles and I got 2 quarts out of it.

I'm going to check it frequently now, weekly at least (500 miles per week). I think I will also run some engine cleaner through it. I have read elsewhere on the forum that I may have a stuck ring and good cleaning may help. I have not noticed any decrease in power or any excessive engine noise. The car had it's Connecticut emissions test last week - no problem there either. No blue smoke that I can see and no oil leakage in the garage where it spends the night.

Any ideas?

By the way, checked my brake pads today - they look new....

Daniel

 

No guarantees, but try a new PCV valve. They are responsible for sudden increased oil consumption on lots of cars.

Look at the bright side, at least you now know to never go over 1,000 miles before checking your oil level no matter how little your car normally uses.

 

Some cars are having this problem. Does anyone know what needs to be done to correct the problem and the approximate price a good independent mechanic would charge. it sounds like valve and ring wear.

 

It is probably cheapest to do an engine swap with a low mileage salvage motor. It might come in at under $1000. Do you have a consumption problem? One thing I have noticed is that in a car with a consumption problem, the owner has a tendency to forget to keep the oil topped up, and as a result, the oil can go so low as to have the check engine light come on for low pressure. Even worse, owners that don't add oil until the light comes on. For those reasons, I think any engine with a consumption problem would need a complete overhaul, and I cannot see that being cheaper than just grabbing a low mileage motor from a salvage yard and having it installed.

 

It's not an oil consumption problem, it's an Owner's Manual problem.

The Prius has one of the worst owner's manuals I have seen. Some of the Prius specific information isn't to bad but a lot of the stuff in there appears to be a "cut and paste" job from other manuals.

I can't imagine where the 1 quart per 600 miles came from though, I don't think Toyota has ever built a vehicle that wasted engine oil at that rate. Maybe it should have been 1 quart per 6000 miles, that would still be to much but more reasonable. The real question is why haven't they corrected it?

 

Claims of 600 to 1000 miles/qt being acceptable are common by car manufacturers. It allows them to weasel their way out of a lot of engine oil burning warranty claims.

 

Surly burning 1qrt of oil in 600miles cannot be doing the cat any good, (the one in the exhaust not the furry one that just ran past) they go bad very quickly when covered with oil and that will ruin emissions.

 

I agree. I think manufacturers set the bar high, obviously hoping to head off warranty claims. I'd be concerned, very concerned if my vehicle was burning or going through a quart every 600 miles. But just because the manufacturer might set that as the standard doesn't mean the vehicle does or should burn that much.

Even my 15 year old + Honda Accord didn't consume oil at that rate. If I bought anything new that was? I don't care what the manual said, I'd be complaining.

 

Currently 58,000 miles on our Prius. I change the oil every 10,000 miles and replace with only 4 quarts, not 4.4 quarts. When I change the oil it nearly fills a gallon container. Oil is Mobil One true synthetic 0W20 oil.

alfon

 

I realize this is a dead thread, but then again I am reading it due to my google search for "prius burning oil", so another post might help someone some day. I have a 2007 Prius and at around 130K or so I started getting the red tringle of death when I would go around tight turns. After a couple months or so of this I checked my oil and the dip stick was bone dry. It made me wonder if the last oil change might have forgot the part about adding new oil after draining the old oil. Whatever happened, it has been burning about a qt every 600 miles since then. I have 180K on it now. And BTW, I still have about 50% of my brakes left. Anyway, things can happen with the oil consumption. I have no idea what happened with mine. I never even checked the oil b4 then, assuming my 5K oil changes took care of that. I think it might be possible that the rings can get frozen in their lands and not rotate around the piston like they should. I am not sure that could cause oil burning, but it can happen and is not the way the engine was designed to run. At 180K I am noticing a little less power and more fuel consumption.