Did the test. Drive, break and accelerate and it's still knocking. Parked and accelerate to 1500rpm still ticks. Forgot to mention, tick is faster with rpms.
Oil pressure on start:
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OK, good to know that in the not too distant past the engine ran quietly & this came on
gradually over time. (As opposed to a barn find start up where the noise was there
from your beginning with it.)
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If it was me, I would show him this oil reading & ask him what's his definition of low oil pressure?
Not being confrontational, just trying to reconcile his diagnosis vis-a-vis the gauge reading?
Has he proved/disproved the accuracy of your oil pressure gauge? Or just pulling this
broad-brush diagnosis out of his back pocket based on previous experience?
Others feel free to jump in & correct me, but I've found that changing the engine oil viscosity
for the purposes of troubleshooting this kind of scenario will help me decide if the problem is an
out of tolerance rod bearing vs piston slap/knock. For example, if you are running 5W-30, then
changing to a 10W-30 or 10W-40 and having the noise either change or remain constant would
tell me which way to go. And of course, if you are running a 10W-30 oil, I'd switch to a 20W-50
oil & repeat the listening session. (After all, it does have 190K miles on it.)
If the sound diminishes or disappears, then we know that you are towards the end of the service
life of the rod bearing. In this case, by adopting the new (work around) oil viscosity, this will buy
you some breathing room in order to come up with a solution that works for you.
And if the noise remains, then now I'm looking at the other end of the connecting rod. Piston slap?
Who knows, some people have driven a long time with piston slap -- more of a audible nuisance than
outright showstopper?
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Of course don't take the above as any kind of guarantee that it won't rapidly worsen if left as-is
and possibly strand you. Until I had a better understanding of what's causing the noise,
I would abstain from towing a horse trailer, boat, toy hauler, etc. As a matter of fact, I would drive it
gently & monitor the oil pressure diligently.
Again, there's several folks with a lot of experience urging you to dig a little deeper. Watching
your video, you might be able to start with the #5 or #7 cylinder and locate the noisy assy
on the first couple of tries. Drop the inspection cover & verify the tightness of the bolts
between the flexplate & the torque converter? Or maybe change the oil to a thicker viscosity & listen.
(NOTE: Change it yourself, a lot of Jiffy Lube type joints will write down your request & then put whatever
is in the 55-gallon bulk oil drum anyway. :-(
Anyway, do some controlled testing and report back. And thanks for getting back on whether the
engine ever ran sans noise or not.
My 2¢ worth!