If you click over to www.4x4wire.com and peruse the Isuzu forums...
search for valve noise or valve clatter... they have discussed this
issue to death.
Cause is build up of varnish clogging the lifter oiling ports.
Previous owner probably didn't change oil frequently, and possibly
even used a high-viscosity petroleum oil (10w40 or 20w50) which makes
the problem worse. Never use anything over 10w30 in this engine.
Most common solution seems to be usinig an engine flush (several
choices... Gunk, Seafoam, plain 'ol kerosene). Then use 0w30 or 5w30
Mobil1 exclusively to clean out the ports for several changes. Once
the noise goes away, change oil religiously never more than 4k between
changes (if using petroleum).
I had to do this when my engine turned over 90k... now (at 125k) it
only occasionaly ticks, for a short while when it does.
I have also had less ticking with Fram, Pennzoil or STP filters. Pur1
filters caused much worse ticking problems, not sure why.
If flushing a couple times and running Mobil1 doesn't do it you may
need to remove the lifters, clean them in solvent, re-prime and
reinstall them if you want a quiet motor.
Does the ticking actually cause any harm, or is it just one of those
annoying things that can be safely ignored? I've noticed our 94 Trooper
(128k) ticking very badly on occasion right after starting. Usually goes
away after about half a block after engine speed gets up a bit... I've
never really noticed it any other time...
Can't say... but many people on the 4x4wire forums have reported no
harm and their's had been ticking away for quite a while.
I don't think it's uncommon for most any engine with hydraulic lifters
to tick for a while soon after startup. That just illustrates the
point that oil oil pressure is slow to build throughout the engine.
One thing I've notice, though: the thicker the oil viscosity used the
more likely it is to tick for a while and cold oil is thicker than hot
That would make sense...I've been running 10w30 havoline since we got it at
about 115k. Only time it does it is dead cold after not being run for many
hours. Seems a bit worse in cold weather. Guess I just won't worry about
Honda recommends 0 weight oil for this engine. It is the consistency of
water, IMHO, and is supposedly great for the small (really small) oil
ports in the rocker arms.
I had this ticking problem in my '95 Passport. Spent the time, did the
work, replaced the rocker shafts and cleaned out the badly clogged
HLA's, and now the engine runs great.
The ticking starts when the HLA's no longer allow the rocker arms to
perform their job, and allowing the valves to open up all the way.
It can only be deterimental, INMO, over time to allow the ticking to
continue. As it gets worse, engine performance gets worse.
I gained at least 50 miles per tank and about 10-15 horsepower out of my
engine performing this work.
There is a service bulletin about this ticking problem which Honda has
put out and which tells how to fix the problem.
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