oil consumption

How much oil are you using? My son's car doesn't use any more than normal.

Dan D '99 Impreza 2.5 RS (son's) Central NJ USA

I'm loosing about 1 quart every 4000 miles or 1.5 litres every 5k kilometers ~ or thereabouts

How much oil are you using? My son's car doesn't use any more than normal.

Dan D '99 Impreza 2.5 RS (son's) Central NJ USA

That doesn't seem particularly excessive to me. How many miles are on your car? How often do you change your oil? I assume it's an '04 Forrester....

Dan D '99 Impreza 2.5 RS Central NJ USA

Indeed, many manufactureers will not begin to entertain a warranty repair for oil consumption until it reaches 1 qt. in 1,000 miles!

Can't imagine having a new car and being stuck with that!

Still, some soob drivers do find bad/dirty PCV valve/systems can lead to high oil consumption. maybe have that system looked at.

Carl

One quart in 1000 miles? A lot of companies will not do a warranty repair for less than one liter in 700 KM.

Thats pretty durn close to a quart in 500 miles.

For MANY years, if a car did not burn a quart in 1000 miles, you figured there was something wrong!!!

With today's cars, if everything else is up to snuff, a treatment with Marvel Mystery Oil or Rislone or some similar chemical treatment can often free up sticky rings and reduce the oil consumption to half or less. Particularly if the vehicle has seen "extended drain" servicing.

5W20 oil doesn't help any either - particularly in warm weather. Daughter's 98 Neon goes through 2 or 3 quarts to a change using 10W40 or 10W30 oil respectively - and seldom needs a quart between changes when running 20W50 ** Posted from **

This is a rebuilt short block with less than 6k km on it. The heads (and PCV valve) are from the original motor that had 78k km on it. It had severe piston slap so was replaced under warranty - it was noisey but didn't burn a drop of oil between changes. I wasn't provided any information on the rebuilt block, so I have no idea how many miles were on it - but that shouldn't matter if it was rebuilt properly with new bushings, seals, rings, pistons, and the cylinders honed. The PVC valve is a very good place to start - thanks Carl. Also, this motor is starting to get very noisey like nothing was tightened inside (best way to describe it). The valves rattle or clack now (didn't with the old motor). The timing belt was replaced - is it possible to be off a tooth or have slipped a tooth to cause both of these problems? Power and gas mileage does not seem to be affected.

It is amazing that anybody would try to pass off 1qt/1k miles as normal oil consumption. It seems we're all getting suckered by pretty plastic bobbles and ignoring the decline of quality.

Hi,

Not at all!

There are SO many factors involved in oil consumption that even a given engine will experience sometimes wide variations in oil consumption. For many years the tolerances in engines were greater than they are now, so

1 qt/1000 mi was ABSOLUTELY normal! If one's engine used LESS, that was quite a blessing.

Today some new engines will go 5000 miles or more w/o going thru a whole quart. But don't think they're NOT burning oil--they're just doing it at a very low rate. As the engine ages, valve stem seals become brittle and allow more oil passage, rings wear and/or get sticky, PCV valves get gooey, etc. So don't be surprised if your "1 qt/4000 mi" complaint is met w/ less than perfect attentiveness!

Some people say their engine never uses any oil because it hasn't dropped below the "Low" mark on the stick. Many shops "overfill" engines when they do oil changes. Some, of course, do this just thru ignorance. But others will add an "extra" quarter to half quart knowing their customers seldom check the stick and this gives 'em a bit of "safety factor" before they run low. So "My engine doesn't use any oil" needs to be defined and qualified.

Then we have engineering parameters. A figure of 1 qt/700 km was mentioned. For many years, that was pretty standard w/ many German cars. The reasoning was that out on the autobahn, running wide open for prolonged amounts of time, the engine should be loose enough to let some extra oil thru everywhere to keep it lubricated and prevent excessive wear, perhaps even seizing up. Japanese engines have been at the opposite end for quite some time, being very tight and using very little oil. I've been led to believe that early in the game (at least before oils have become what they are today) this was problematic w/ excessive wear to the engines under such use.

So... if you came to me w/ your "problem," I'd be polite and try to explain to you w/ a straight face you have no problem. I imagine your dealer will do the same.

But before going there, do you do your own oil changes? If so, do one. Use the "proper" oil grade for your driving conditions from the manual, and see where you stand. It's hardly unusual for shops to put the wrong grade in: for example, I spent 600+ miles in 100-110 deg F temps on a trip this last week. 5W-30 and 10W-30 are both ok'd for my vehicle according to the book. The shops will put in 5W-30 all year, but this time of year, I use 10W-30 as the consumption's less. A friend, w/ the identical engine, uses 10W-40 and uses less than I do. And his engine's got 250+k miles, mine "only" 100+k!

Point being, if you've got the wrong grade for the conditions, you may experience "excessive" consumption, even if everything else is "perfect." You may also wish to try one of the "high mileage" oils to see if that has a positive effect. If your valve seals are getting a bit stiff, these products can sometimes help. Synthetics are known for getting varnish out of many engines, and generally burn off slower than dino varieties. There are many things you can try.

Good luck w/ your "problem!"

Rick

Rick - you're right on the money - thank you. I am probably feeling a bit freaked by having a rebuilt engine installed that I have no info on (warranty replacement), and now has gone as noisey as the one that was removed after only 5k km. I guess I've been very lucky with the vehicles I've owned over the years. Only one - a Mitsubishi Gallant - had an oil consuption problem (valve seals), and that was after 200k km. Every other car or van I've owned burned almost nothing. Carl already pointed out the PCV valve, and I'll be checking that tomorrow. This is my first Subaru, so I have no experience with the boxer engine. Quality was why I went to Subaru in the first place, so I hope I didn't offend anyone.

Thanks for the insight.

There is no question Subarus exhibit a few quirks not present in other makes and you were wise to seek out some specific info. In one sense or another Subarus are 'high performance' (or 'special duty') vehicles and either the AWD system, or turbo chargers or other aspects will require the owner to be a little more diligent and likely spend a little more money (if only for tire sets) than many other makes. However, ALL cars, after a few years, can exhibit virtually any automotive problem. Subarus are not immune from design oversights, qulaity control mistakes, uncaring dealership staff or owner abuse. Rick and others here have a lot of experience. I have only owned soobs since late '02 . I certainly wasn't offended. In fact, I recall when I first learned how intolerant manufacturers were of oil consumption complaints. Decades ago a co-worker had purchased a new Trans-Am (IIRC or Camaro?) and could not get a warranty ticket written even though he could document 1qt. in 900 miles of oil consumption! I don't think anyone claims it is typical or even 'normal'. Just not warrantable (is that a word?)

Carl