Piston Slap: Wither WRX?

Mark writes:

I have a 2003 WRX with 198,000 miles. Only non-standard maintenance repair so far was a new driver side head and valves at 165,000 because a valve was hung and the head was starting to crack. Everything else, including clutch and turbo are original. Unfortunately, now the vehicle is burning 1.5 – 2qt of oil every 1000 miles. There are no leaks. I am tempted to trade it in for the nominal amount (Maybe $1-2k) and take advantage of the current new car incentives. However I hate to buy a new car if I can just feed this paid for WRX oil for another 20-30,000 miles. What do you think. Should I feed the car oil until the engine/turbo explodes or retire it and get another car?

First off, let me say that I am not a Subie Genius, and there could be a good (cheap?) answer to this problem if you spent a good hour digging for information on a Subaru forum. And with that, I’ll give you my causes for this problem:

Clogged PCV valve compounded with engine blow by. If you don’t know how old your PCV is, get a new one immediately. Blow-by is a common problem on many older cars, especially those running under forced induction. Installing a breather filter (not legal in some states, but not hard to revert back to stock) in place of the oil filler cap will help. At your mileage a new PCV with breather filter is a good idea.

Check for blue smoke coming from the tailpipe, especially right after you twist the key. With high mileage come larger tolerances in piston rings, valve seals, turbo seals or bearings. Not a big deal, that’s what happens when a car ages. And WRXs aren’t known for long-term durability, anything with a turbo is gonna have issues at this mileage. If you really wanna know, get a compression test: but that won’t be cheap on a boxer motor.

Maybe you can squeeze more life (20-30k, as stated) if you keep going as-is. Maybe things will get better if you switch to thicker oil, or maybe things will get worse.

I’d recommend driving some new cars, see if you fall in love with something, and then get a feel for the market with an ad for your WRX on Craigslist. You’re gonna be in for some serious cash outlay one way or another, so you might as well have some fun while there’s still time.