Noise from engine no lights on

Knock, knock...who's there?
Engine crank shaft bearings are shot.

Lifter noise is typical of an oil pressure issue, or when oil channels are clogged from infrequent oil changes.
You can start by changing the oil and REPLACING THE FILTER. Marvel Mystery Oil or other oil treatments will help clean the oil system and quiet the lifters. If an oil change and crankcase oil additive helps quiet the noise, change your oil every 500 miles for at least 2000 miles, and the lifter noise is likely to stop.
Are you getting a CHECK ENGINE light, or an OIL PRESSURE warning? Have ODB codes checked, and be prepared to replace the oil pump or oil pickup tube, especially if the car has over 150,000 miles. Once you have correct the issue, change oil more frequently.

take it to an accredited service shop that has experience on your make of engine and have a proper diagnosis done and quote
it is possible that there is a spinning main bearing and the test is a oil pressure test using a mechanical gauge
some times it spins , low oil pressure -knocking other times it stops and the oil pressure goes back up , knocking stops
should I be correct , normally it can be repaired in car by removing the sump and replacing that bearing shell, of the shaft is not damaged
i would steer away from a new engine or suggestions of a blown engine but it could be serious

if oil all the way to the top mark in dip stick?
did you put 0w oil in a car that must not have that? RTM.
cold only, how long
hot only ?
both?
and does not stop? making noise?

change your oil and filter, the tapping is more than likely the lifters trying to get lubed once the oil gets to them it stops

Could be lifter noise...valve cams, parts of the engine, are supposed to move the valves up and down to let in air and let out exhaust...there are lifters that good between the cams and the valves to make sure the valves are tight against the cams, they maintain the tightness even when things wear...when the lifter stops doing its job, it lets a gap form between the valve and the cam, and a tapping is heard, actually metal hitting against metal...this could be from the lifter being damaged, dirty, or starved for oil...make sure your oil level is right, make sure the oil is clean...sometimes a dirty lifter can benefit from a fresh oil change...if the tapping keeps up, damage can occur to the valve ends or cam shaft...you probably wouldn't notice the engine not running as well, unless damage occurred that caused to valve to stop working...there are lots of other sounds from the engine that are bad, like persistent knocking, which is a piston in the act of breaking, and not so bad like ignition knocking from using too low an octane gas...depending on the engine type, tapping could be lived with for years, and sometimes lifter replacement, if needed, can be fairly inexpensive...good luck...

1995 Ford Windstar 3.8L Engine Knocking noise on top side of engine near center of Air Plenum. Engine was completely rebuilt 2 years ago (28,000 miles on Re-Built Engine/ 156,000mile on Van). Coolant level is SAT, Engine oil level is Sat. Van was driven 2800 miles since last oil/filter change. Engine started surging as van slowed down to make a stop then engine shut off. Restarted engine and heard knocking noise. Shut engine off immediately. The oil light flickers on dash with engine running. Do fuel injectors make tapping noises when degraded? Is it possible hydraulic lifter not able to leak down or does not fill with oil? Oil pressure issue with the dash light flickering? I can see if the engine has allot of miles on it, the intake and exhaust valves begin to leak-by how ever this not the issue. Where do you start to locate engine knock noise? How is oil pressure checked to see if pressure is too low? Any help where to start would be appreciated.

hi,the first thing to do is an engine flush,then refill with10/40 or 20/50 oil, semi sythetic,not forgeting to change the filter.this particular engine is quite loud but the noise should die down after about 15/20 secs if its tappy.i would also reccomend adding wynns or another oil additive to help the self adjusting tappets quiten down.An oil blockage would show up as a loud knock (big end rumble)and the oil warning light would show on the dash.
after you do the oil change rev the engine to 3000 for 30 secs.this will help to get the tappets right.

Most likely it is the rockers tapping the lifters. the crankcase has only leftover oil in it at the start, and has to wait for the oil pump to get it there.
I would add a stablizer to your oil...like LUCAS. It may help a bit with a cold engine.
If the knocking is in the piston, then you should see some indication on the spark plugs...like oil or blow-by build up.