2001 Impreza OBS, M1 5W30, 5k on oil, 159k on car

[kaesees]

Hello BITOG. I've been lurking here for a while and I've finally done my first UOA. It's for my 2001 Subaru Impreza Outback Sport with ~159k miles (purchased last year at 146k). The OCI was 5k miles and the oil used was M1 5W30; previously, Valvoline conventional oil was used. The beginning and end of this OCI were the first and second oil changes I've done myself. After taking the sample I knocked the bottle and lost about 1/3 of the oil therein, so I topped it off with oil from the filter (I noted this to Blackstone, though they didn't mention it in their comments). Without further ado:

My thoughts:
- I'm glad the headgasket looks good (no antifreeze)
- TBN looks pretty darn good and viscosity looks good; extending the OCI to 7.5k in the future seems reasonable. The EJ22/EJ222 must be easy on oil.
- I assume the numbers for calcium, magnesium and phosphorous are off from the averages is because the average additive pack and M1's additive pack differ; am I correct in this?

The iron and lead wear metal numbers are a little high though, so I'm considering following Blackstone's advice and doing another 5k OCI and getting another analysis done. Then again, I'm only hoping to keep this car going until 210k miles (that's when the timing belt, water pump, tires, and a host of other things all need to be done) so I'm not sure whether slightly high wear numbers (for a 5k interval versus the 4.2k interval the averages are based on) are anything worth worrying about.

 

[EddieCairns]

The Subaru boxer engines vary on Iron, my 70k mile car after 9k miles on the oil was at 19. As iron tends to trend with mileage your reading is not too out of average for a Subaru but some show less iron.

Copper can be high due to the particular oil cooler fitted to some Subaru cars but your car is low at 2.

I wonder if lead at 7 is a big problem on a 160k mile car.

I would go at at least 7k and would not worry about a longer interval.

That car in the UK was on 7,500 miles OCI in 2001.

As of 2005 Subaru UK increased the OCI to 12k non turbo and 10k for turbos.

eddie

 

[Rosetta]

If you're going to do another UOA, I'd sample at 4.5k and see condition before running it much beyond 6k. If it's good at 4.5k, then I'd try 7.5k and try to get results w/o make outs.

 

[cptbarkey]

the 2.2 is indestructible and the head gaskets simply do not fail except for deliberate abuse. rest easy and keep on what you are doing.

 

[bluesubie]

Yep, the 2.2 was a great engine!

I'd probably run conventional unless you exceed 7,500 mile intervals.

-Dennis