Well, let start at the beginning. I purchased a Ford f-150 1998
extended cab. 3 weeks ago I had the oil changed with
high mileage oil.

two days ago, I went out to start the truck after it had been
sitting for 3 days without starting, It started the turnover
process did a really loud clunck ( booming ) like the engine
had seized up.. it didn't crank, I tried it three more times
with no luck.. I sat that %&*#$$$ and waited about 5 minutes
and tried again.. It started.

Now I have a tapping noise when the motor is running very
loud on initial start up.. but fades ( not completely) on increase
in speeed.

This noise I have always associated with valve tapping.
Any ideas on what happen, how big a problem to I have
and Can it be fixed without spending a fortune ( I just lost
my job). Will it run long in this manner.. and can I put anything
in the engine to quiten it down.

I appreciate any and all feedback to a novice truck owner.
by the way the truck has 100,000 miles on it.
thanks
F-150 in trouble.

 

I don't have a clue about the clunk. However, in the extreme cold, I have heard the light tapping that goes away. It seems like a long time ago I heard about "piston slap." I guess it could or could not be it.....