QuestionQUESTION: The sump oil level in my 2002 Outback has risen rather quickly after the last oil change done around 3000km ago. The Subaru service centre has suggested it could be a faulty fuel injector/s. Is this possible? The car has only done 60,000km. We have not noticed any change in driving performance, but drive fairly gently. Are there any other symptoms to look for if it is a faulty injector.
ANSWER: The 2002 Outback is not really known for injector failures unless it is a early production vehicle with a manual transmission.
If you had a failed injector the vehicle would run poorly, the check engine light would come on with either a misfire code or O2 sensor rich or lean code set.
Is it just possible that the oil level is a little overfilled and as the oil expands with heat the level is raising further?
Does the oil smell excessively like fuel? If not, than the injector is not at fault.
Hope that helps
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QUESTION: I think you are right- the oil level was 50mL to start with. I have done some further investigation, refilling the oil myself, improving my measuring technique and checking fuel economy.
I have found the dipstick very hard to read consistently, particularly if the oil level is up near the twist in the stick above the hot full notch. When we took it in complaining the oil was overful, Subaru reset the level
"exactly". I was still getting high readings particulary when hot. I have now dropped the oil myself and refilled it with the same oil to "exactly" the cold full mark, I had 0.4 litres of oil left over ( and probably lost 100ml or so in the process). With the car heated up the oil level was bang on the hot full notch. Have only had a couple of short trips since, but so far the oil level has not changed.
By some measurements and calculation I made along the way,I estimate adding 0.4l of oil would add 8mm to the level or up to around the "hot full notch".
So when the oil heats up and rises another 10 mm it reaches close to the first twist in the dip stick, where I find the level almost impossible to read. With the twists in the stick it seems to collect oil as you draw it out of the tube. After you try it a few more times it seems to get worse as the oil clings to the inside of the tube.
Is this a common problem with the Subaru?
the Subaru service agent advises they put in a measured amount of oil and hence cannot overfill the level. I had noted the oil overfull after several services. I even took it back twice once for them to fix it. Next service is was overfull again, so I stopped checking.
Will too much oil damage the engine?
Thankyou for your previous advice. It was most helpful and prompted me to do the investigation above.
AnswerHey Trevor,
So I am in the States, and I am so used to Quarts and inches when referring to measurements. Even when a measurement is given in cm the habit is to say a quarter of an inch etc.. So having said all that, a cm on the dipstick past the full mark is not very much oil at all neither is two or three cm either. Here is the most likely scenario, when the oil is changed the engine is either cold or not all of the oil is allowed to drain out say a 1/4 of a quart or so stays in the engine. Then it is filled up by measurement rather than need. So we start out over filled cold, and then as the oil expands it shows up even higher on the stick. I don't think you have anything to worry about but if you want to get to the real bottom of the issue try the following. Run the vehicle until it is up to operating temperature, shut it down and allow it to cool for a few minute than change the oil. Be mindful that the oil is hot and try not to get burned. Give the oil time to drain out especially when taking off the filter. Now when it comes time to fill it up, add one quart at a time until it is at the bottom line of the dipstick, note the amount. Run the vehicle, shut down and check the level(you will need to add more oil to get back to the lower line), note the amount of oil that it takes to get back to the lower mark. Check the oil three times at each interval and average it. Now comes the tricky part, note the amount of oil you add to get from the low to full mark and keep this number in mind. The oil will expand some more after the oil reaches operating temperature. Due to the design of the engine and the oil pan, a little excess oil will show up very high on the stick as it has nowhere to go but up. In my experience unless the engine is 1 or two quarts overfilled you will not do any damage.
I hope this helps and I am sure the answer is here.
Justin
All Wheel Drive Auto.
Your Independent Subaru Specialist.
