Jay wrote,
>When starting up my Series V after sitting for a week or two, I often
will
>hear a loud tap,tap, tap noise coming from under the hood. It would go
a
>way after a driving a couple blocks or after restarting several times.
I
>have been worrying about it and the last time it occured I also noticed
the
>oil pressure was zero. After the tapping went away the oil pressure
>returned to 40 which is where it always is on my car when it is
running.
>Any ideas of what is going on? I suspect the oil pump but any
suggestions
>would be appreciated.
>thanks
Sorry to say Jay, that the tap tap sound is most likely rod bearings
knocking while the engine is running without lubrication.
Valves can make a bit of noise till the motor tolerances stabilize
during warm up, but the best clue to your problem is the fact that
the oil pressure comes up after the tapping goes away. Ive seen
quite a few high milage engines make the exact same noise on
startup.
The ever so common stuck oil pressure relief valve should be
considered, but these failures tend to be more permanent in
nature.
As far as the oil pump being to blame, as the clearances increase,
the oil leaks by the rotor easier, and the oil that is trapped in the
filter
and base assy, drain down into the pan. This causes oil starvation
on startup, and could cause the problem that you seem to be having.
The oil pump, would not cause an intermittent condition, unless the
oil pump drive pin had been sheared, but then again, the distributor
drive would probably be lost as well.
If you plan on replacing the oil pump, replace the rod bearings as well,
as it is not normal for them to clatter so on startup.
Good Luck!
Jarrid Gross
This archive was generated by hypermail 2b30 : Tue Sep 05 2000 - 09:41:51 CDT