2003 WRX w/ bad piston rings and rod knock



My 2003 Subaru Impreza WRX 2.0L Turbo had developed minor rod knock and is eating up oil, which both lead me to believe that my piston rings are bad. Because one must pull the engine in order to pull the pistons on the Subaru boxer engines, which would be very expensive, i’ve decided that I have two options: 1. Have my existing block rebuilt. or 2. Replace the block. I’ve looked into replacing my block with a new one, and it looks like it’d run me around $6,000 with labor and parts to do it right (which is waaay out of my price range). I’ve also looked into replacing it with a used block w/ 44,000 miles on it, but it does not come with a warranty. This option would run me about $3,000, which is more around my price range. I’m wondering if anyone could offer any advice as to which option I should go with, or present me with any other options that I haven’t thought of. Thanks!


If you live in the Northern part of the country, just park at the bottom of a hill during a snowstorm. End of problem.


Investigate why a 2003 vehicle needs this level of internal engine work. Would you be putting money in a vehicle that has a design error?


The subaru turbo boxer engines have been known to develop rod knock (which I found out after I bought the car). Some of them go for upwards of 200,000 miles, and others develop rod knock early like mine.


Boost pressure, or how often it’s applied, can often be a contributing factor to piston and rod problems.

The odds of this engine needing far more than piston rings is very very high; as in block boring, oversized pistons, crank grinding, etc. and this means a complete engine overhaul.
No way could I see sinking 6 grand into this car.

If the car were mine I’d use patience and try to find a good used engine that could be heard running before buying it. (car with a trashed transaxle, collision, etc.)

If you go with a used engine, no matter the mileage, you should replace the timing belt and water pump before installing it along with a new rear main seal and transaxle front pump seal if the car has an automatic transaxle.
Many a used engine that did not get new seals have started leaking soon afterwards and the engine had to come back out to replace these inexpensive items.


Thanks for the input. I believe that finding a good used engine is what i’ll have to do.


You might also check with some of the salvage yards in your area about an engine. Some yards will install what they sell for a very nominal fee and if there happens to be a problem with it they’re on the hook for making it right, not you.

Salvage yards will often sell a “guaranteed good” unit but if there’s a problem with it they will either replace the unit or refund your money. However, they will not stand behind any labor charges that you may pay to have it installed so the possibility of having to have the “good” unit removed may lead to another labor charge.
Hope that helps.