Yet another EJ25 overheating saga. 98 Forester overheats. Coolant get replenished, makes it to dealer w/o difficulty. Service replaces thermostat and flushes system. Vehicle runs fine around town (15 mile trips 50 mph or less) for a week until it's time to drive 100 miles at highway speeds to my 35th H.S. reunion. Overheats about 35 miles into trip. Wait 'til it cools off, refill system and drive home at 45 mph w/o incident(no reunion, $90 bucks down the drain and miss some teachers who may not be around for the next one). Back to the dealer...now the word is exhaust (well, emissions is the word they used) in the coolant, the mechanic says he thinks the block has a hairline crack...estimated repair $4,792!! (seen the trade-in value of a 98 Forester L lately?) I have reviewed many of the overheating posts on USMB and also the nice write-up by theotherskip but I can't find any diagnostic tests that would tell the difference between a cracked block (forget it, scrap heap) and a blown head gasket (ok, spend the $ and get a few more years out of it) short of tearing the engine down. Any suggestions??

Thanks,

Mike

Stop going to the dealership! They are not good at diagnosing issues; they are paid to get parts on off vehicles. And most of the time what you tell the service writer never gets to the tec.

Find a local independent Subaru shop, fix the HG or if you have not overheated it too many times or if you have get an engine from CCR.

Cracked blocks are not commonplace. Your headgasket(s) are the most likely culprit.

$13oo new HG, timing belt, tensioners, etc...