2.0 impreza oil light

[rustfarmer]

Our daughter recently bought a 2014 Impreza which had been wrecked and rebuilt (somewhat) so we took it to a dealer and spent $3000 for fluid changes, filters, and safety checks which replaced trans mount, ball joint pinch bolt (wrong undersized bolt had been used), brake fluid flush, and throttle body service. She drove the car for about a month around town and then I did an oil and filter change using factory filter and 0-20 Mobil 1 oil. She then started a long trip and during the first leg from Nashville to Oklahoma City. About 30 miles from OK city the oil can light came on so she slowed speed to 60 and within a few minutes light went off. When she got to her stop she called us and a dipstick check seemed to show the oil level a bit low but hard to tell from her photos. The car only has 79K miles on it, but of course we have no way of knowing its service history. Engine did not overheat or make any unusual sounds and has never shown signs of oil burning. It's at a dealer for diagnostics right now but wondered if the oil pressure sensor is a likely fail, or if there is wiring that should be inspected because of prior wreck and repairs? 

[1 Lucky Texan]

not sure on newer cars but, oil pressure switches are not a common failure, but anything CAN fail.... At least, even on older cars, no worse than other brands...

I'd just let the dealer examine things,they can hook into the oi lpassage somewhere and check actual pressure, inspect wiring and ground connections(which have been vital since the mid-90s with all the computerized parts), etc.

Edited May 2, 2022 by 1 Lucky Texan

[rustfarmer]

Thank you for your reply Lucky. My reading indicates that an oil level sensor exists on the newer models, probably because on older ones once the pressure light comes on you have already damaged the engine. I was wonder if that sensor has issues? Update: Dealer ran tests and says everything including oil level looks fine and they have no idea why the light came on. Good, but also bummer in that now we have no idea if there is an issue or not.

[el_freddo]

Wasn’t there some models fitted with a low oil warning light? Could this be an issue? 

If the issue is wiring and it’s related to whatever crash the car was involved in, it could be an intermittent issue that would be hard to diagnose when stationary. Although if that wire was damaged I’d also think that many other wires would possibly be damaged too. 

Hopefully nothing sinister! Ask your daughter to photograph the light before start up and ensure she’s interpreting the illuminated light she’s seen correctly. 

Cheers 

Bennie

[rustfarmer]

Thanks for your reply Bennie. My reading does confirm that this model has both an oil pressure sensor and an oil level sensor. The dealer said both parts are inexpensive but they didn't want to replace them without a second false reading. They said drive at least another 1000 miles to see if the warning light comes on again. Not a very satisfactory answer IMHO. I would have gladly paid to replace both sensors and inspect the wiring too. Time will tell I guess.

[el_freddo]

Fingers crossed if the light illuminates again it’s not the death nell for this engine. 

All the best! 

Bennie

[rustfarmer]

Thank you Bennie!

[Ferret54]

I would HOPE you never have to replace the oil level switch as this was a many questioned part in early FB engines when the oil USAGE was high. There were some threads on other boards that suggested customers who used Non Synthetic oil could have CLOGGED or caused problems with the sensor, but I never saw one of those myself.

 

I also have a 2014 Impreza and if you have to replace it, YES it does come out with 2 small bolts, Yes the dealer price is under $100, BUT to get to it is a nightmare. If you crawl under your jacked up car, look straight up beyond the oil drain plug. You will see it there bolted into the cast UPPER or Middle oil pan. However the motor mount is right in the way. And to get that out of the way, you have to remove the steering rack OR lift the engine out of the car to remove that motor mount. The FSM has you lift the engine a few inches AND remove the steerling rack. 

 

If this happened to me with an 8 year old car with 155K on it ( my car ) , I might just unplug or find a way AROUND the light coming on and just check the oil level monthly or during every long trip as we used to do before we had so many indicators. As I check tire pressure regularly because TPMS usually come on when pressure is too low. Guess I'm just an old time mechanic with old habits ...... Still have a dwell meter, vacuum gauge and other old still working tools ......

[rustfarmer]

Thank you Ferret54 for this information. This is the first I have heard about this being such a PITA job. I, too, am an old wrench (74 years) and will be looking for some work around if this turns out to be the bad part. What would be an easy way to disable it without the warning light coming on? Have others dealt with this as well and if so, how? Thanks for your help.

[Ferret54]

From the wiring section of the FSM, electrically it's a single wired reed switch with ground provided by one of the mounting bolts. What I don't know is it 'open' or 'closed' to keep the light off. Haven't had to cross that 'bridge' yet. But the single wire connector is easy to access. Look at front of engine just below the oil filter. You see the small single white connector with the wire to the sensor disappearing below the engine by the water pump. May be as simple as unplug it, OR ground it to overcome the sensor and light.

 

Replacing this sensor alone, to me, is not enough to make me do that much work to extinguish a light cars never had for years. The Dipstick still works for me. Maybe if I was pulling the engine for another reason, THEN I would replace it. ...... us 'old' guys think alike ........ I'll be 70 soon..... and working around gas stations or for dealers off and on since I was 15.

[Numbchux]

Yes, that car has an oil level light, and an oil pressure light.

If the oil pressure light comes on on the freeway, the engine is done. If it flickers a little bit at hot idle, you might be able to save it, but at rpm and load....no.

We discovered with my mom's 12 Impreza that the level light comes on pretty early, sometimes the level doesn't even read to the low mark on the dip stick, and only needs about a half a quart to read "full". Hers is a bit of an oil burner, so she's gotten used to carrying oil and a funnel.

[rustfarmer]

Thank you Numbchux for that info. Is there an easy way to disable the oil level indicator (snip a wire?) if it is giving false readings? Dealer said oil level was spot on.

[Ferret54]

I 'played' with MY14 Impreza and came to the following conclusion.

The oil level float/reed switch CLOSES ( grounds ) to turn the indicator ON.

I unplugged mine and with the engine running touched a ground to the engine harness, the indicator came on AND stays on even after I removed the ground. I SUPPPOSE this is to keep the indicator ON and not just a quick flash when it first senses the oil low, maybe from low and a hard corner.

Next key Off / On engine running, indicator was still OFF with the connector unplugged. Since mine seems to be operating correctly, I just replugged the connector.

Hope this helps you .... If unplugged, you are fully relying on manually checking the level via the dipstick like we've done for so many years.

Edited May 4, 2022 by Ferret54

[rustfarmer]

Nice. Thanks so much for your help Ferret54.

[el_freddo]

I wouldn’t be disconnecting the low oil warning light - it’s there for a reason! 

That’s also your daughter’s safety net if she’s not checking and tipping off the oil regularly. 

My 5c worth anyway. 

Cheers 

Bennie

[rustfarmer]

Thanks Bennie. That is our decision too. The occasional false warning will be a reminder to check the dipstick just to make sure. If the warnings become too frequent we may price having the unit replaced.

[rustfarmer]

Update FWIW. Daughter reports oil level is within normal level but perhaps could take a half quart so she added about that much (although she said she spilled quite a bit so who know exactly how much was added). Light was off for a while, then came on for ten minutes, that on and off some and finally on steady. She will check in the morning when dead cold to get exact reading. Engine seems fine with no noises, excess heat, nor tailpipe smoke and she has run about 9 hours today. Frustrating for me and wish this part could just be replaced more easily. I will post again when I know more. 

[Numbchux]

I'm not sure replacing the part would have a different effect. It's my understanding that they are very sensitive. My mom has said many times that she can only put in about a 1/2 quart when the light comes on before it's at the "Full" mark. She keeps a paper funnel tucked in next to the battery....

[rustfarmer]

Thank you Numbchux. That seems to be our experience as well.

[rustfarmer]

I have done further research on this issue and turns out there is a tech service bulletin about reprogramming the ECU so that the low oil light only comes on when you are 1.1 quarts low. This seems like a bad idea, but is a band aid due to the excessive oil consumption issue on these engines. I found a youtube video (mrsubaru1387) which claims the real problem is that corporate made the decision to try to get extra fuel mileage by building these engine to "looser" specs. Apparently even a class action lawsuit a has been settled which resulted in Subaru replacing entire short blocks for some folks, but that did not help the issue and thus some owners actually got a buy back. The excess oil use can foul plugs, catalytic converters, O2 sensors, etc. My question now is, might it make sense to use a different weight oil, even if this reduces fuel mileage a bit? Color me frustrated!

[rustfarmer]

No thoughts anyone? I was thinking 5 w 30 might be a help.

[forester2002s]

Yes thicker oil will help to reduce oil leakage. And the loss in fuel economy will be minor.

[heartless]

agreed - 5/30 should help

my 2004 runs 5/30 and i get around 27-28mpg overall average. Not sure what the mileage numbers are supposed to be for the FB series engines, but for the EJs that is pretty typical

 

[rustfarmer]

Thanks heartless. Our 2013 Crosstrek was getting 28 mpg at 120K miles but after tuneup and throttle body cleaning it now get 31 to 32. It runs 0-20 oil and never needs any between changes I do at 6K. FWIW, a dealer service advisor I like just told me about a product he swears will reduce oil consumption by about half. He says B G Engine restorer is a engine flush that actually works! He recommends just before an oil change get the car a quart low; add a quart of this product (available on amazon and some parts stores); run the engine for 10 minutes; stop engine and let cool (which I assume helps the product dissolve deposits); restart engine and run 5 minutes and then drain while still hot (be careful!). Complete oil and filter change--oil will be black as tar. Do this for two normal oil changes and oil consumption should be greatly reduced. He did not recommend using thicker oil, but we'll see. I will try this soon and report my findings. May still go to 5-30, but I'll try this first.

[Numbchux]

Yea, the oil consumption suit happened about 6-7 years ago (right in the middle of my time at a Subaru dealership), extending those engine warrantees to 100k miles. And yes, the rings in the replacement short blocks are tighter, and fuel mileage will suffer.

My mom's 2012 Impreza has a salvage title, and so is not covered. It's now over 200k miles, and I think burning a quart of oil every thousand miles, or so. And it's intermittently throwing a P0420 code (cat converter efficiency, likely due to all the oil gone through it over the years).

 

And yes, I've heard from several sources I trust to switch to a synthetic 5w30.