Apparently the timing belt tensioners from subaru are 100% hydraulic,
and are quite prone to issues, not coming up to tension quickly
enough, and generally being unreliable. I know mine is about to have
the 6th Subaru timing belt tensioner put in in its 110k mile lifetime
because a brand new one put in about 10,000 miles ago turns out to be
defective. Apparently it's the root cause of my periodic missing on
acceleration problem I've had ever since that preventive maintenance.
Lack of tension on the initial startup after the job is likely to
blame for the belt jumping a tooth, damaging the belt, and
intermittently allow the timing off just enough to be an intermittent
pain in both my and my tech's ass.
Apparently, as the story further unfolds, not only is there a TSB on
the issue (which was followed to the letter on the actual replacement
of the belt), but upon the re-replacement of the belt, and manually
turning the engine 10 times (vs the prescribed 3) this thing still
hadn't come up to tension. As the story further unfolds, we learned
that aftermarket tensioners apparently include a spring as a backup to
the hydraulic tensioning, and once it's pumped up to tension it wont'
recede the way a Subaru tensioner would. Subaru relies only on the
hydraulic action to tension, and has no backup.
So yet again (in addition to the stories of aftermarket head gaskets
being superior to OEM sube), we have a story suggesting strongly that
aftermarket parts makers have done what you'd expect expensive OEM
parts to have done -- fix design flaws.
Anyone with experience have data points confirming or denying this?
2001 Legacy Outback Wagon, 2.5L H-4
Chicago, Illinois USA