'02 Focus 2.0 sohc lost compression in #4 cylinder. Well, didn't lose all of
it. #4 is at 60 psi, others are 160 or more.
Is this Focus engine prone to any catastrophic failure or do I pursue the usual
suspects like burnt valve, blown head gasket, holed piston, etc?
Somebody *please* tell me this is a chunk of carbon stuck in a valve seat and
not something that's going to put me swapping engines for the next week or so.
Turns out it was a loose valve seat on #4 cylinder. Apparently this is a common
failure on some Focus engines. This one had a little over 68,000 miles on it. I
found a good used head in a junkyard for $100 and I'm getting it swapped out
today. The junkyard guy said they sell a lot of heads to correct this problem.
If this turns out not to be the cause of the dead miss and lost compression,
I'll post the results here.
Just came from the mechanic's shop. There is a section of the valve seat
missing. Not a big section, maybe 1/2" long. It's not hard to tell where it
went. Just look at the top of the piston. :(
The damage to the piston seems to be superficial. I used to be a general line
mechanic for a Ford dealer and before that I was building air cooled VW engines
for fun and profit. I told the mechanic to put the new head on it and we'd run
it until it blows up, then look for a whole engine.
It may last for years, it may not make it out of the driveway. But I've seen
worse looking pistons that hadn't given any trouble. It's a chance I'm willing
to take. It's really a no-lose situation. I either need a new engine now, or
I'll need one later. The switchover cost will be the same either way. I've
already bought the head and I can't take it back. If I get another year or two
out of this engine, that's another year or two I have to find another if I need
it. If it outlasts the rest of the car, great. If it lasts long enough that
the car isn't worth fixing, that's a plus too.
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