Oil Rec for Subaru Impreza NA with High Consumpt?

[Ty Williams]

Hello,
I have a 2005 Subaru Impreza 2.5RS. This is the 2.5L, SOHC normally aspirated model, not the turbo. The engine is currently just shy of 80,000 miles and is burning about 1qt of oil every 1,000mi. Between the consumption (yes, the engine is headed for a rebuild but I just can't afford it now) and the fact that they jacked the price of Redline up to $10/qt, I can't afford to keep putting Redline into it.

If it makes a difference, the engine is burning the oil, not leaking it out.

I need to switch to something much cheaper. Preferably something at or under $5/qt. I realize I'll likely have to shorten my OCIs to account for the switch to a lesser oil but with the rate I'm consuming it, it will still cost less. This car is both my daily driver and our race car (road rally, rallycross, and autocross). Here is the UOA from the last sample I sent in. Older sample is on Royal Purple 5w30, newer sample is on Reline 5w30.

Based on all this, what would you guys recommend I use until I can afford to have the engine rebuilt?

 

[dishdude]

How hard do you rag on this engine?

 

[Ty Williams]

Really, really hard.

 

[Johnny]

Pennzoil Platinum 10W-30

 

[Ty Williams]

Pennzoil Platinum is only about a buck cheaper than Redline around here.

 

[Johnny]

How much does Shell Rotella T Synthetic 5W-40 sell for in your area. Its robust and might help some with the oil consumption.

When you rebuild that engine you might want to get with FrankN in Kentucky and try the Mobil 1 15W-50 he runs in all of his cars. If your going to continue racing it you need something more robust that a 5W-30 with current SM specs.

 

[Ty Williams]

You know, I've been keeping an eye out for that Shell Rotella, but I have yet to actually see any on a shelf in any of the Big 3 autoparts stores or even in NAPA.

 

[sicko]

Have you given any thought to using a high mileage oil to fight the burn off? Maybe, Castrol GTX HM, or MaxLife. If you feel the need for a full synthetic, then MaxLife comes as a full synthetic, but it's fairly difficult to find.

Is the oil burning the only reason for the re-build, or are there other issues

 

[Johnny]

Wal Mart carries it. It's in a blue gallon jug.

 

[JayhawkRoy]

O'Reilly's current ad PZ Plat = 3.99/qt. Stock up or try at least one oil change.

 

[Ty Williams]

The rebuild is due to the oil consumption and the fact that the car has seen a significant decrease in power and fuel economy. The newer Subraus switched to hypereutectic pistons and they've been cracking/breaking ringlands left and right. The assumption is that one or more of my pistons has a cracked ringland.

 

[JAG]

FWIW, I had a 2002 Impreza RS and it too had high oil consumption from day 1 and Red Line doubled the oil consumption rate over all of the several other oils I tried. This was consistent and happened over tens of thousands of miles. I never figured out why. Your UOAs seem to indicate the same trend between Red Line and Royal Purple but the UOAs were taken far apart in the mileage of the engine. Did consumption increase with the engine's life or was it due to oil differences?

I also notice how much higher the Royal Purple's TBN was than Red Line. There's no contest. Were conditions and engine tune comparable, making it an apples to apples comparison?

I'd try a synthetic 5W-40 or 10W-40 in cooler weather and if cost is an issue a mineral 15W-40 HDEO meeting CJ-4 in the summer.

 

[Ty Williams]

On this forum, I've read that RL typically shows lower TBN than other oils, so I'm not worried about that at all.

Oil consumption has increased steadily over time. I've actually tried Pennzoil Platinum, Redline, Royal Purple, basic full-dino Valvoline, GC, and a couple of others, all had similar consumption rates. For a while, about 9 months ago, I was doing an "oil change" (not really, more like a test) where I would drain the engine and fill with a new brand of oil. Then I'd wait to see how long it would take it to eat a quart of the new oil. It it was as short or shorter than the other oils I'd tried, I'd just go ahead and drain and change to another oil to test. Never did find anything it liked. I didn't, however, try any of the high-mileage oils.

Which is why I'm hunting for a recommendation for a cheap oil that won't suck until I can get the rebuild done.

 

[Eddie]

Any name brand HM oil in a 5 qt jug would be my choice. If you indead have broken ring lands then the piston rings are scoring the cylendar walls. Not a cheap rebuild I think.

 

[Ty Williams]

Nope, I'm planing on having to start with a block, get it bored out 0.5mm to accept 100mm pistons, and basically starting from scratch.

 

[mva]

Check the pcv system - is it plugged?

 

[Ty Williams]

I don't think it's plugged, I end up with quite a lot of oil in the catch can connected to the PCV system (which I then dump back into the oil filler tube).

 

[Audi Junkie]

PZ 10w-40 or MaxLife 10w-40

 

[Ty Williams]

What is "PZ"?

 

[buster]

Try Amsoil 5w30. Low volatility.