99 Forester, 172.5K miles
I bit the bullet and bought some KYB struts, mounts, and related parts so as the title suggests, I'm all in for the long haul. I'll drive this thing until the rear quarter panels rust away.
I replaced the clutch and ball joints about 5K miles ago so the next big repairs on the horizon are the timing belt and head gaskets. The car has the original head gaskets - still no coolant or oil seepage, let alone leaks. Assuming they're still holding at the next timing belt change, should I preemptively replace them?
For your EJ25 (not all Ej25's), preemptively replacing them is almost pointless for a variety of reasons:
1. they don't always leak
2. when this particular variety EJ25 starts leaking it begins really slow seeping externally, causes zero issues, no risk, and you can drive them 50,000 miles leaking...you'll have plenty of time to repair them, preemptively repairing them buys you nothing except extra work that may have never been needed.
3. they may have already been replaced - though you sound confident they're original
what i would rather focus on is:
1. have they ever been replaced before? you seem convinced they're original so that's answered.
2. replace the coolant and add the coolant conditioner. they leak often but they also make 250,000+ miles without replacement
3. replace the timing belts with a complete timing belt kit - all new pulleys and tensioner, ebay has great priced kits, many here prefer theimportexperts though their prices are higher now than they used to be. with a timing belt replace the cam seals, reseal the oil pump, tigthen the rear oil pump backing plate screws, and replace the water pump. be sure to use a Subaru water pump gasket (aftermarkets are a joke) and Subaru or XACTA thermostat.
if you do replace the headgaskets, resurface the heads and use the EJ25 Turbo headgaskets, otherwise you're just installing the same headgaskets prone to fail to begin with. the turbo gaskets don't fail.
if it was a different EJ25 then preemptive is a great option, some have significant issues with reliability and extensive damage if they blow...not so with yours.
when the clutch was done was the perfect time to do them, the engine/trans already had to come out of the vehicle, saving much of the labor. but again...not a big deal on yours so move right along.
timing belts are super easy on that car, no need to time those with headgaskets.
Edited by grossgary, 30 March 2013 - 09:19 PM.