Hello,

I have S60 2.4 2001. Today after I started the engine one valve knocked very loudly. I checked this with my father and there we were no doubt that ONE valve i knocking. I was fortunate to have some tools we me and I have taken out the cover from timing belt to check its tension. It was ok. I decided to travel. With time the knocking sound was less noisy and at some point it disappeared. Instead when I was driving approx 35 mph at steady speed there was a strange sound. I am not sure where it was from. At first I thought that it comes from transmission. It was not distinctive, more like gurgling and some luck of power occurred with him. It lasted couple second until I not accelerated or have taken my foot from the pedal. After I spotted it couple times It looks for me more like the sound you hear after you started the engine after oil change. It look simply as whole cam and valves would work with out lubrication. Malfunctioning cam operation would also explain some decrease in power.

I checked the car after one hour drive. The valve was not knocking, and the engine did not want to start with out pushing gas pedal.

What it could be, how this could happen and how to fix it?

Regards
Mario

 

Now I investigated better this situation. Car starts to work as old diesel at 1600 rpm during slow acceleration. Strange sound is coming from inside the engine, I would say from cylinder head.
Anybody has idea what is creating this problem?

 

It almost sounds like you're describing piston slap which is caused by excessive piston skirt to bore clearance. As the engine warms up, the piston expands and the noise diminishes. Has the engine ever been overheated?

 

It does not happen on cold engine. Only after warm up.

 

Answering you question it was not overheated. But it required to add 1q of cooling fluid. I do not think so it had a problem with cooling that time at least the temperature gouge did not show any overheating.