What you hear is likely a lash adjuster collapsing. A lash
adjuster does one of the jobs of a hydraulic lifter in
pushrod engines. In the Ford 4.6L V-8, it is under one end
of the cam follower sometimes called the rocker lever
from pushrod engine nomenclature. The lash adjuster is in
the head and supports one end of the cam follower with the
valve on the opposite end. The cam is in between. On cold
startupm the lash adjuster is extended to take up any
clearance in the valve actualting mechanisim just like a
hydraulic lifter. The proble with the 4.6L V8 is that it
has relatively small oil passages which become restricted
and in some cases blocked by sludge. The problem is
aggraveted by cold, dirty or too heavy oil viscosity. In
some cases, the problem is caused by restrictive oil filters
because of its design or just plain in need of replacement.
The problem can be helped in many cases by the use of the
recemmended 5w30 oil for that year or by the 5w-20 oil Ford
later recommended for all it's car engines. As in years
past, a good quality oil is more likely to help. Almost any
current 5w-20 or 5w-30 oil will meet a higher spec than that
in effect when that engine was built.
Keep in mind that this may be a stubborn problem that does
not respond to any combination of oil or filters. The
problem can deteriorate to remain noisy even with the engine
hot. If it gets bad enough or there is enough clearance
when the adjuster is noisy, the cam follower can slip out of
position and not operate the valve in which case the engine
will have a dead cylinder and possibly other problems. If
this happens, it can usually be repaired by removing the cam
cover and replacing the lash adjuster and reinstalling the
cam follower. You may need the special tool to put the
follower back in position if you are not very creative with
Lastly, the noise may be coming from the cam chain tensioner
which is located on the lower right side of the block. It
functions similar to the valve lash adjuster above and can
be effected the same by oil restrictions or heavy oil during
warmup. If either of these are the problem, there is not
much to be done in most case until you are ready to do some
major work on the engine. My own CV has had this problem
for the last 175K miles. Once the engine has warmed a bit,
the noise goes away. I fully expect the car to die of
several other causes before the noise can get it.
SOMETIMES running something like Marvel Mystery Oil or Rislone in the
oil can disolve the gunk that is causing the problem and make the
noise go away.
It depends how badly neglected the motor has been. There is ALWAYS the
possibility that you will make the problem worse by trying any
chemical fix, but usually it is worth a try. Not doing anything may
cause the problem to get worse too - and will definitely not make it
In my experience (not on that engine ) there is something about 75-80%
chance that carefull application of these products, with associated
oil and filter changes, will solve the problem.
One of the risks of not changing engine oil "too often" and thereby
wasting money and oil, is having these kinds of problems occur with
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