ps2 clunking sounds

Don't know if this is the right forum for this but anyhow. I'm trying to play half life 1 on my ps2, but everytime I put it in the ps2 and itmakes loud clunking and scraping sounds, and most times the game won't load. The disc is clean on both sides, not a single scratch on it, it's in perfect condition I don't understand why it's having this issue, none of my other games do.

Phat or slim?

phat

Sorry, I've only really worked with slims. :/ Have you tried opening it up to find the source of the mystery noise?

I have not opened it up, it seems to be only from the disc, cause no other disc I put in has this problem

That. is. strange. No cracks in the center ring or anything?

nope, there is nothing visibly wrong with the disc, it's litteraly in perfect condition

Absolutely no idea...

When did you get your ps2?

Is enough air flowing into the system?

ummm the only thing that might fix the problem is buffing the lens

be sure that the game isnt broken becasue i got a perfect dreamcast game and it didnt read either

all it takes is one little scratch to make the disk not read even though im sure u knew that