What is “normal” oil consumption?

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I just took a 1400 mile trip and used a quart of oil. Using the car for work, hardly any oil is used in 1400 miles. The only difference was the trip was mostly over 3000 RPM but it rarely goes much over 2500 RPM going to & from work. This has happened twice to me, once on synthetic & once on dino. Called Nissan dealer and they said that a quart/1000 miles can be considered normal. Car is a 02 SER with about 30000 miles.
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Yes, it is normal for some engines to consume more oil when ran at higher rpms.

And yes, many manufacturers consider up to 1qt of oil consumption per 1k miles still 'normal'.

Personally though, I would not be a happy camper if my new car with only 30K on the odometer burned through so much oil.
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Want to see something scary go to the Nissan web site look under recall. I have a 2004 SE-R and quickly called the dealer. Somehow the oil can get in the cat and cause a fire.
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Bamaro, i've always taken a half litre (nearly an eigth of a US gallon, I suppose your quarts are different to an Imperial quart too)per 1000 km (600 miles) as an acceptable oil consumption in a new car. That would be a little under a quart per 1000 miles.

But what sort of driving had you been doing prior to this trip? Because if you'd been driving around town, short trips, then what you might've seen is fuel dilution.

I used to have people questioning me all the time about sudden oil consumption increases. They'd drive their car to and from work, or around the town to the supermarket and to pick up the kids from school, then take the car away on a long freeway trip. They'd be amased to find when they checked their oil that they had used a litre or more oil on the trip.

Well, they hadn't used the oil on the trip, they'd used it running around town but the engine had 'topped up' the oil level with fuel dilution from cold running - the fuel in the crankcase had never been evaporated because the engine hadn't reached a high enough temperature. Then when they head out onto the freeway, the engine temperature climbs and stays high and the fuel dilution evaporates, and the oil level goes down.

Fuel dilution happens in all engines, but usually in a petrol (gasoline) engine it is burnt off.

I remember once when doing a trial of a generation 5 railway locomotive HDEO in a group of GE locos that the viscosity of our oil was dropping and causing the oil to be condemned at about 90 days - this oil eventually lasted over 300 days in service once the problem was solved.

There was fuel dilution happening, by the time 90 days were up there was nearly 10% of fuel in the crankcase. The operator was concerned that this generation 5 oil was suffering viscosity drop when a competitors generation 4 oil wasn't.

It took a lot of used oil analysis - including gas chromatography because the fuel was being 'topped' (that is the lighter components were boiling off) to discover that there was just as much fuel dilution in the competitive generation 4 oil as in our generation 5 oil.

But the generation 4 oil was oxidising and thickening and the fuel dilution was thinning it and that balanced things out so the oil/fuel mix remained at approximately the same viscosity as the new generation 4 oil.

Once the fuel dilution problem was solved, they installed low sac injectors, the viscosity drop disappeared and the generation 5 oil lasted more than twice as long in service as the generation 4 oil.
 
First you have to define normal. For warranty repairs it varys from 1 Qt per 1000 miles to 1 qt. per 800 miles. I belive some posted that their car company uses 1 quart per 750 miles. Most well designed properly functioning engines that have been well maintained will burn less then a quart per OCI.

I would not be too alarmed at this happening just one time. Often your oil will get fuel diluted from constant short trips and cold starts etc. A long trip gives the engine enough time to burn off all of these contaimanets and the oil will show a slight drop. If you combine this with a slightly higher sustained engine speed you could arrive at one quart with no major issues.

With the above said if you can afford it now would be a great time to do an AUto-Rx treatment as a preventive measure in case this oil consuption is a syptom of dirsty seals or ring pack!

You might also try driveing the car at slightly higher RPM's to see if it was soley RPM related some engines are RPM sensitive for oil consuption.

I am not trying to confuse you I just want you to consider the possablitiys!

[ May 19, 2004, 09:11 PM: Message edited by: JohnBrowning ]
 
Another figure I have seen quoted on GM V8's is 1 quart per 100 gallons of fuel, as being "normal".

My Duramax diesel used no oil pulling a 12,000# loaded trailer from Ohio to Florida, and back empty to Cleveland.(Delvac 1300)

My 2000 1 ton 454 powered pickup burned a quart of 10W30 Amsoil towbaring a Jeep Grand Cherokee down to Marco Island from Cleveland, one way. Go figure.
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[ May 19, 2004, 10:58 PM: Message edited by: Pick ]
 
Change the air filter (no kidding). On our Isuzu Trooper (3.5L 24 valve V-6) it burns oil particularly at high rpms with anything but a very recent air filter.

My theory is that the crankcase vacuum is out of spec at high rpms with a dirty filter. A lot of Troopers are for some reason serious oil users, but not all. There has been a lot of discussion on Isuzu groups.

I tested this theory recently when we drove to Colorado for skiing. ~1000 miles up burned quart. Get new filter before going home and burned no oil, and didn't through next oil change.

Also make sure your PCV system is clear.
 
quote:

Why might I have to add oil between changes?


volatility -
Volatility is a measurement of the amount of oil which is lost during engine operation because of burn-off.

There are several concerns associated with oil volatility. First, engine oil is lost and must be replaced. Additionally, the viscosity of the remaining oil increases. Moreover, oil loss could change the effectiveness of the oil as a lubricant. The chemical properties and additive package ratio of the oil may also change as the volatile components are burned off. Finally, there is also evidence that the volatilized oil may damage the exhaust catalyst as it passes through.

The volatility of an engine oil is measured using ASTM test method D5800. A known weight of oil is heated to 250°C in a special chamber and held at that temperature for one hour. Air is introduced into the chamber and maintained at a constant flow rate under slight vacuum. After one hour, the amount of oil remaining in the chamber is weighed again. The percentage of oil lost is determined by comparing the remaining weight of oil with the original weight of oil.

Specifications set by ILSAC determine that the amount of engine oil lost through volatilization at 250°C for one hour should not exceed 22%.

 
I'll take a simpler route.

Have you checked your throttle body for oil migration? Suppose a valve cover baffle or faulty PCV or CCV is forcing oil to migrate via the intake vent to the intake stream. This would be exacerbated at higher rpms.

You can also be entering "new" frontier on your ring travel limits due to some minor variance in bearing clearance at higher rpms.

Can I assume that this 1400 mile trip involved long stretches at over 70 mph? ..where the hp required allegedly increase by the square over it?

...and..

what weight oil are you using ...and what does the owner's manual say in regard to extend high speed driving?

I mean ..you obviously don't have a problem outside of these conditons ..so the problem isn't likely with the engine per se'. If it had a consumption problem ..it would probably be present all the time.

[ May 20, 2004, 11:38 AM: Message edited by: Gary Allan ]
 
I guess what I consider normal is 1/2 quart per 3000 miles. All my vehicles are right around that. My 3800 consumes no oil at all, I consider that ideal.

-T
 
SteveS, my day to day driving never involves short trips. Its 23 miles each way to work over mostly 2 lane highways traveling 30 - 50 MPH so I dont think it would involve any oil dilution.
Gary Allen, my typical driving on the trip was 66 - 75 MPH range or about 2800 - 3500 RPM, mostly around 3000 RPM which really isn't that high and I burned about 45 gallons of gas meaning there was about a 180 - 1 ratio of gas to oil.
The oil was 5w-30 as recommended by Nissan and I only had about 1100 miles on it when the trip started.
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