Greeting,

I looked for a solution all over the forum, watched all the videos with the same problem and replaced all the recommended parts. But there was no progress. I bought the car in such a condition, the engine has been swapt and traveled 150km and it started to sound like that a(the previous owner does not know what oil they put it when replacing the engine), I have a new 5w-30. 502/505 spec



At first, I suspected the cam tensioners, which are the most common problem, ordered a replacement (ESEN SKV) and during the replacement I noticed blocked hydraulic lifters, replaced them with correct ones (I have another engine with damaged cylinders and valves), assembled it, put it in phase and tried to start it.

The problem is always the same.

I repeated the same thing for the head on the passenger side (there was a correct original cam tensioner from the engine for parts) on that side there were fewer blocked hydrolifts, assembled everything, tried to turn it on, and the matter did not improve at all.

I forgot to mention that first of all I checked with diagnostics (vag com lite) for errors that were not there after canceling and starting.

The engine runs smoothly, the only problem is that sound like a knocking crankshaft.

After that, I suspected that the signal to the tensioner was faulty, and the measured voltage when the ignition was on was 8.6V (12.4 battery)

And during sea operation, it dropped to 6.5v

After that, I connected the external power supply to the sensors and tried turning them on and off while the engine was running, but I didn't hear any significant differences in the engine operation (I also tested the resistance on the cam tensioner coils and they are all in the correct range of 13-15 ohms)

The only thing I didn't check was the oil return valves under the intake manifold.

But if they are the problem then the sound should subside after the oil reaches the tensioner.



I don't know what else to try/do, I'm in the process of removing the engine, so I'll try to remove the heads and get to the crankshaft to see what the condition is (I removed the crankcase and didn't find any large pieces or contamination.)




If anyone has any other advice, I would be very grateful.

The sound is constant and increases with engine revolutions.
Video is bellow:
https://youtube.com/shorts/lnG6uQN6D-E?si=_7gleQiO-C-dEVO2

 

That doesn't sound good. I suggest you get a stethoscope and listen to the engine to find the source of it. That seems loud enough to quickly identify. Remove the serpentine belt and run the engine to see if the noise goes away. I suspect you may have already done these things as you are in deep already. Are there any codes? If you have a borescope you could also pull the plugs and look in the cylinders for evidence of damage. Or pull the manifold and look at the valves.

 

One thing I notice is that you hear the starter noise and its clean but after its started the noise appears.

 

I removed serpentine belt in the beginning, another clue is when i tryed sarting the engine witout valve covers the oil is spraing from the cam tensioner, but it shouldn't. When the oil preasure builds up the cam tensioner valve must shut off(remainder cam tensioner is new)
I'm suspecting low oil preasure, but straingly no oil preasure warning indication.

I dont have borescope nor stethoscope, i tryed lisening by ear but it sounds like in the mittle below intake manifold.
Ill give update after i remove the engine and tear it up.
Video engine running without valve covers, oil spraing from top of cam tensioner:

 

You can do it with a long piece of wood or a long screwdriver if you don't have a stethoscope. Just put one end on the engine and the other on your ear and move it around until the noise is loudest. The timing of the knock also seems to align with the cam lobe rotations.