Sunday I finally got my 1990 4Runner with a V6 engine back together
after replacing the left side head gasket. Before I took it apart 4
of the 6 cylinders had good compression. I replaced the left side
head gasket, radiator, water pump, all belts, and some various vacuum
lines and hoses I saw to be questionable. The left cylinder head was
taken to the machine shop to be cleaned and milled. The shop also did
a valve grind and adjusted the valves. I did not remove the right
side. Now, none of the cylinders is building compression.
Could someone tell me where to start diagnosing this? Why would the
right side not be building compression if it was fine before? What
did I do wrong?
Any help is appreciated.
Absolutely no compression: you either forgot to install the timing belt,
or have it installed incorrectly.
Fluttering compression: again the timing belt, probably installed
incorrectly. Did you follow the alignment and installation procedure?
Those marks are pretty critical.
Unless you did more than remove a head, that's the best guess at your
And to echo the comments of another poster: if you have to mill a head,
it is often best to mill both, as there can be slight differences in
compression after milling, and it is best to balance them. Not
critical, but best.
take a look at the timing belt.
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