We've all heard it from somewhere by now; "The new Subaru engines are no good, they consume oil" or "why are they using a 6000 mile interval on a 0W20 oil ?". Well friends I'm afraid I thought these things as well in the beginning, until I owned 2 of these vehicles and never saw a single issue...
So what gives? Why are thousands and thousands of these engines in service right now, still performing respectably well past the 100,000 mile marker....yet the small percentage that do have issues are cried about in dealership service departments or on forums leading to this stigma Subaru carries today? Seems unfair doesn't it? This is exactly why I'm writing this, so that through my education and experience in the automotive industry we all can adopt better engine care practices that I use myself with excellent results. Lets start with the engine break in:
Engine Break-in Procedure
If you are the first owner of a new car or are having the engine replaced, you should do a break-in procedure. A new engine block has a fresh crosshatch pattern cut into the cylinders, this is where a new piston ring will slightly grind against the pattern to create a matching surface for the two metals to make a seal. Two sealing rings and two oil rings per piston, times four cylinders. Then there are all of the Main and Rod bearings, bushings, and every other metal part that will wear off it's superficial surface. See how that adds up to a lot of wear metal in the first batch of oil? Good.
Now I know some are thinking; "don't they do a break-in on the engines at the factory?". I don't know exactly what they do since I've never been there, but I have watched many assembly line videos on the internet from various manufacturers. In all of these videos they start the engine and run diagnostic tests and maybe run the vehicle on a dyno to test the transmission, but thats all. The rest is on us, the end consumer. I've included a link to my favorite "Engine Break-in Procedure" Website HERE but I don't follow the whole thing. Heres my personal break-in process:
1-Change oil to conventional or a high Zinc formula right away, and drive using about 3/4 throttle and some deceleration in gear(or in "L") for 500 miles.
2-Change the oil again at 1000 miles (conventional oil is cheap), and reset the fuel trims.
3-Change to the recommended oil at 2000 miles, then resume recommended 6000 mile interval.
At this point some would say that break-in is complete, but thats simply not true. I've attached my latest oil sample from my 2018 forester below and even at 8000 miles you can still see small traces of bearing(copper) and piston ring/cylinder(iron and molybdenum) material lingering. So keep that in mind when you're thinking about hitting a track-day in your new car. That leads us to the next part, oil and the interval.
Engine oil and the Interval
Please believe me when I tell you I've seen a LOT of oil analysis reports on various makes and models, and using a variety of oil brands and viscosities. I frequent the Bobistheoilguy forum to learn how other manufacturers equipment is holding up and what oil they use, and I'm going to summarize everything I've learned in three steps.
1-Choose a synthetic oil you want to use, theses days they are all performing very well so it doesn't matter.
2-Send in at least one sample of a regular interval, and see what Blackstone reports and recommends.
3-Don't listen to anyone else.
You can see from my report that the factory-fill 0W20 withstood a full 5000 mile interval, in San Diego traffic, idling for long periods as my kids sleep, and daily full-throttle pulls to get onto the freeways. So this time we are going 7500 miles based on their recommendations, and I'm sure that will be fine as well. I've already seen many FB25 oil analysis reports pass 7500 and go on to 10,000, but I'm not going to exceed the factory recommendations that far.
In addition to using top-teir fuel and the CORRECT OCTANE, some other maintenance items to consider on the FB25 are:
1-Engine air filter every 12K miles
2-Throttle plate cleaning at 30K miles
3-Spark plugs at 60K
4-Coolant at 120K
Items to inspect regularly:
1- Inspect for oil leaks- If the FB/FA engines develop an oil leak it can foul the Bank1 and Bank 2 Oxygen sensors, and they are not cheap.
2- Water pump weep holes- I've seen some leak at 60K, and some last to 200k.
3- Drive Belt- They seem to last between 60-80K before they start to dry out and crack.
4-Intake tube and PCV system- I've seen the intake tubes start to slide off of the air-box, and the PCV hose cracks/splits and develops an air leak.
5-Listen for noises- I'v had engines with a noise complaint at 40K, and the cam/valve clearance was out of specification. That was rare, most of the FB/FA engines I work on don't need an adjustment until the 100k mark.
Every so often the manufacturer will develop Engine Control Module software updates to improve drivability, charging, oil level detection, extended cranking, or improved idle. The only way you will get these updates is if you go to the dealership and request them. If your vehicle is still under warranty then you will not have to pay for these updates, but if you're not covered any longer be prepared to pay the standard diagnostic fee.
I believe that covers it for the FB25 engine, but of course the rest of your vehicle will need regular service and inspection as well. For those items just refer to your owners manual, but I may do a write-up on the Subaru CVT's as well later on to clear up any misconceptions. See you guys next week!
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