Alas, I’ve learned from a local mechanic (who has worked extensively on Subies) that our Outback has an “interference engine” that virtually ensures the valves will be damaged if and when the timing belt goes. He guaranteed me the valves are bent on both sides and guesses the engine has no compression. He has estimated $2500 in repair costs, depending on whether he can find remanufactured heads (or has to have a machine shop rebuild them). The only local shop he trusts is booked months out. Luckily, I have other vehicles to use for now.
I’m an engineer, but not into engines and automotive repairs (except by necessity and for cost-savings). What I find so thoroughly disappointing is that the failure of the timing belt in this type of engine will invariably lead to very costly repairs (bent valves at a minimum). I guess the experts will say, “You should have replaced your timing belt before it broke!“. In my defense, I was told (by the used car dealer I bought it from several years ago) that the timing belt had already been replaced. Besides, people come to own cars a lot of ways, and the repair history is often not well-documented. It’s easy to say, “take it to the dealer and get it checked out“. I’ve dealt with our local dealer on many occasions and avoid them like the plague. They are WAY over-priced and have occasionally acted unethically (but that’s another story…).
Can anyone explain/justify the use of interference engines when they will invariably get trashed when the timing belt (a component that will inevitably fail and often catastrophically and with no warning) breaks? A used car dealer told me that roughly 60% of new cars have interference engines, so their use is clearly not universal. Are there substantial advantages (more power, reduced fuel consumption, etc.) to these types of engines? Do all Subarus have interference engines?
While I’m ranting, I have to say the limited access to the valve covers (located on opposite sides of the engine, very close to the frame) is a very poor design! The valve covers can only be removed by taking out the engine (or, in a pinch, unbolting the engine from the frame and jacking it up slightly). The spark plugs are exceptionally difficult to access. It all makes me wonder what the heck the engineers were thinking. They obviously weren’t concerned about ease of repair and maintenance!
Both of my other cars (a ’91 Saab 900S and ’89 Honda CRX Si) are a world of difference in terms of engine accessibility and ease of maintenance. On my Saab, the distributor cap can be removed, checked, and cleaned without any tools! On both cars, the valves and plugs are exceptionally easy to access. While both the CRX and Saab have interference engines, replacing bent valves is reportedly relatively easy. While these cars don’t have AWD, both provide exceptional performance and value (even now, 30+ years after they were manufactured).
My conclusion (from owning 3 Outbacks and having several costly repairs) is that the engine design essentially locks users into expensive repairs and challenging maintenance. Because the heads are so difficult to access/remove and are almost guaranteed to be severely damaged in the event of a timing belt failure, repairs are very costly. Another example: when we had a cracked valve on our ’06 XT (shortly after buying it from a private party), our local dealer actually recommended we replace the entire engine. They explained that the engine would have to be removed anyway (to replace the valve), so we might as well pay $8,000 and have a new one installed. Fortunately, we found a local mechanic who replaced the valve without removing the engine for a small fraction of what the dealer wanted to charge us.
If I decide to pull the engine myself, can anyone recommend a machine shop that specializes in rebuilding Subaru heads? I live in Oregon and would prefer some place in the Northwest, but will ship them elsewhere if need be. I would greatly appreciate any thoughts or advice. This may be our last Outback…
