[zz_denis]

Hello!
I tried to search but nothing came up really.
The past couple of month my car was making a really strange noise - when engine is completely cold, for example after sitting in garage for two days, i start it up, it starts fine. Then after maybe 5 seconds it starts making this very strange ?clanking? noise, it's very difficult to describe. It's as if one of the pistons is an inch longer than the others and its knocking on the head constantly. Then after it warms up a little, probably when the engine temp. needle is at 0 mark, usually takes about 5 min or so, the noise becomes quieter, quieter untill it completely goes away (when engine warms up completely). This is only occuring when the engine is COLD. Once it warms up i can shut it off/start it again as much as i want and there is no noise. However when it cools down, same thing happens. Note that the noise starts only about 5 second after i start it, not right away.
Not that it's really bothering me THAT much, its just intresting what could be causing this.
If anyone has any idea please let me know!
Thanks, Dennis.

 

[JohnBunneIl]

Switch to a decent thin viscosity synthetic oil. I recommend Mobil 1 0-20.

 

[Supra_N2O]

most likely a valve tap...they can get annoying. try measuring valve clearences as per the online TSRM and adjuting them if needed

 

[jurkey77]

This exact thing happened to my dad's toyota 4x4 pickup. it could be the same problem. What it could be is that one of the cylinders isnt firing up properly. He did the same thing just let it idle for a while till it warms up. He never did fix it though cuz he bought a Toyota Tacoma.

 

[BARTON]

zz, I have a similar concern. What kind of car do you have? The noise goes away as oil pressure builds up. I have had the problem for about 4 months now and have not been able to find it either.

 

[SuprAng]

could also be an exhaust leak

 

[mdr40z]

If it is a low sound it may be a piston slap.... which is one of the skirts hitting the cylinder wall, usually only happen when cold. I had a Nissan the did it for forever, usually isn't fatal and is caused by slightly oval shape wear of the cylinder wall

 

[p5150]

I had a sound that was bothering me as well - it sounded like a metal grinding noise - almost like when you crash engage a starter but slower. But it only lasted a few seconds so I attributed it to a ps pump or ac compressor...... Who knows.

Its not your piston slapping your cyl head so calm down. If that was the case your car wouldnt run.

Ill go with mdr40z and guess piston slap.