Mitsubishi L200 Rattling Noise: Causes & Fixes

Here is a L200 with a 4D56T engine, which has a 2.5-liter displacement.

The engine is making a rattling noise, as if the valves and pistons are colliding, and it's not running smoothly. However, the valve timing is correct, and the valve clearances are also within the normal range. I couldn't find anything unusual in the entire valve train. I also checked the glow plugs to see if I could spot anything, and then I measured the compression.
Cylinder 1: 34 bar, Cylinder 2: 28 bar, Cylinder 3: 32 bar, Cylinder 4: 34 bar. Cylinder 2 is a bit weaker, but I don't think it's related.
Could it be that a nozzle is dripping or that the spray pattern is incorrect? However, I've also checked each line individually, and the hammering sound was still there, so I don't think it's related to the nozzles.
Since it's still a pre-chamber engine, it's possible that a pre-chamber is loose. However, I've had other engines where the pre-chamber came out without making any noise; the pre-chamber rests against the engine block for a portion of its length.

Here's another video. In this video, he didn't make any clicking sounds from second 7 to 15, which was the only time he didn't do so.

[Edit Admin: Better video further down in the thread]

Hi,

In my opinion, the good compression values speak against piston-valve collisions. And you've already ruled out the injectors by disconnecting the fuel lines.
I suspect it might be a loose pre-chamber, but I'm not sure how likely that is with this engine.

Best regards, Rainer.

Remove the valve cover and visually inspect the camshaft and hydraulic lifters.

Hello,
Can you check if the noise occurs synchronously with the Northwest (NW) position while the motor is running? It's not possible to see that in your recording. Perhaps you could stick a small piece of yellow Tesa tape onto the NW wheel to make it more visible.
The regular ticking sound – assuming we're talking about the same noise – isn't very loud. I remember hydrocollaps sounds being louder. However, I would take a look at the surfaces.
Is it possible to run the engine without the auxiliary components?
hg
Herbert.

Rüdi wrote:

Take the valve cover off and visually inspect the camshaft and lifters.

I already checked it, and it doesn't have any hydraulic components. I removed the camshaft and inspected the rocker arms and camshaft, but I didn't see any signs of wear.

@Herbert
I've already run it without any auxiliary devices, and it makes the same noise.
It's not really ticking; it's more like a knocking sound.

It's strange, because you can hear the knocking more clearly in the original file, and also in the YouTube link.

Hi,

Quote:

It's strange, you can hear the knocking more clearly in the original file, and also in the YouTube link.

It would have been better to upload the original file directly.

Best regards, Rainer.

In the original file, the knocking sound is present between 7 and 15 seconds, except at 9 seconds where it is only briefly audible.

Deleted - basic things misinterpreted!

Perhaps I'm mistaken, but I think that when the noise disappears, you can hear or feel the machine moving or vibrating.
Best regards, Frank.

Yes, that's true, but it doesn't run very smoothly either.

Several years ago, I experienced a similar noise in a Toyota. Initially, I suspected worn connecting rod bearings, but after inspecting them and finding them to be in good condition, I concluded that the problem was with the dual-mass flywheel. There was no noticeable change in the noise when the clutch was engaged or when the car was stopped.

I'll check with a dealer to see if this car has a dual-mass flywheel (DMF) installed. According to the parts catalog (Stahlg..), it doesn't.

I also removed the vibration damper (V-belt pulley) and ran the machine without it, but the noise is still present.

Hello,

Considering the age, overall condition, and mileage, aren't these actions a bit excessive?

To me, it sounds like a belt-driven system... AND it runs better than any TDI.

SG
Manfred.

It's definitely not a bearing issue in the belt drive; everything was replaced 30,000 km ago.
Everyone must decide for themselves what they put in.

The connecting rod bearing on the second cylinder has seized.

chli1976 wrote:

The connecting rod bearing on cylinder number 2 has rotated.

That must have been quite a mess.

chli1976 wrote:

The connecting rod bearing on cylinder number 2 has rotated.

Hello.
Sorry for reviving this old thread.

I have a L300 4D56 2.5 with a very similar problem.

Was there only a problem with the connecting rod bearing, or did you also have to replace the crankshaft and connecting rods?

Thank you.
Best regards,
Christoph.

The KW unit was also defective. The customer brought in a used block, but it also didn't last long.