Today is cold.... and when the engine is cold, I can hear slight nocking sound, that depends on engine load.... It is not detonation....

May be bearings....????.... Oil pressure is good (2-3 bar at idle and up to 4.3 bar when engine revs up....).

Your suggestions?

Thanks!

 

Try a thinner oil? Your oil pressure may be good, but your flow may not be good if the oil is too thick at start up in the cold. Also a filter that does not flow well can be a problem.

 

I've just replaced filter and oil (5w50 Syntetic).... This evening engine will be cold... So I'll test it...

 

How cold? 5w50 should be fine aat startup, though that is too thick at warm. 5w30 would be more appropriate.

 

30dgr F.... Not so cold....

 

Likely just a sticky hydraulic lifter. Common problem on these engines but nothing to worry about. Some engine flush prior to each oil change might help.

 

Pablo,
you're '89 3L OHV has flat tappet hydralic cam lifters instead of the newer roller hydraulics....flat tappets create more noise if one is dirty and sticking or not pumping up quickly on engine start

pour in a pint of toulene or acetone into hot engine....let run for five minutes...then set for 2 hours....change oil....will clean the lifters nicely

if above chemicals are not avail....use 1 quart of high grade kerosene such as jet fuel...same technique....into hot engine....run 5 minutes....let set 2 hours....change oil

with flat tappet lifter cams, one does NOT want to run SM rated oils....extreme pressure, antiwear and friction modifier chemical levels are too low....cam/lifter wear rates will be too high....
use a diesel rated 5w40 synthetic oil for your cold climate...diesel rated CH, CI4+ and CJ have extra EP, AW and FM for high load diesel and older flat tappet gas engines
i don't have the EU corresponding oil ratings handy
good luck

hydraulic flat tappet noise was something we lived with 20+ years ago with all engines having them and the poor multi viscosity oils we have avail. then
no 5w50 for 1969 Ford 429ci Cobra Jet, engine rattled when cold like had 10 lbs of marbles in it....until the old 20w40 pumped up the lifters 10 minutes after firing up

 

Use AutoRX, that is probably one of the best engine cleaners out there, provides better lubrication that other solevents, though it works slower.

 

The most interesting, that noise depens on engine load.... It appeares when I press gas pedal.... I heard, that lifter noise is constant and depend on RPM only, not the engine load....

 

Try decarboning the engine, maybe a sticking valve or something. My Mazda was ticking till I decarboned it.

 

I've just drow to my work (5 miles).... Noise was slight, but I hear it....

It was no place on parking so I leaved her near office... Well, I was near computer I and looked in the window.... what I see? free place on parking... so, i decided to occupy it.... I drow my van and... NO NOISE... It dissapeared again.....

 

This is really sounding like a little bit of buildup on the backside of a valve that either causes seating problems, or sluggishness in a valve. Try a decarb treatment and see what happens. Make lots of smoke. Make enough smoke that we here in America can see it.

 

How to do it on 3.0? Any tips...?

 

loose timing chain noise?
will change with load as torque puts slack on one side...will be worse in cold weather when oil is thick and cam turning resistance is higher

timing chain has higher wear rates with manual tranny due to higher rates of rpm change...auto tranny engine does not drop to idle between shifts

had a Chev small block 350 jump a tooth once because chain/gears were worn so much....double roller with 150k miles....no loose chain slap in this case but power dropped when chain jumped teeth...could touch chain together between cam and crank gear!

when chain breaks=lots of noise and can come out thru thin steel cover plate

 

why noise dissapeares when the engine is hot? and 20 minutes ago I draw to the market.... the engine was not warmed up... but no noise... nocks in the morning only