Loud Clatter On Cold Startup.

[JNG3]

'08 5.3 iron block AFM 12,000 miles

 

When the outside temp is below about 35 degrees I've noticed that apon the first startup of the day the engine clatters like a diesel for anywhere from a few seconds to over 30 seconds. Once warmed up the clatter goes away. After the first startup of the day it does not do this again. The clatter does increase/decrease in tempo with rpms. I have not noticed this when the temps are above the mid 30's. The filter is the proper AC/Delco and the oil is changed every 3000 miles and is 5w 30 Havoline. Is this the infamous 'piston slap'? If so I guess that's fine and dandy. From what I've heard, piston slap is supposedly harmless to the engine/durability. I just wondered if it could be something else.

[mkelly]

'08 5.3 iron block AFM 12,000 miles

 

When the outside temp is below about 35 degrees I've noticed that apon the first startup of the day the engine clatters like a diesel for anywhere from a few seconds to over 30 seconds. Once warmed up the clatter goes away. After the first startup of the day it does not do this again. The clatter does increase/decrease in tempo with rpms. I have not noticed this when the temps are above the mid 30's. The filter is the proper AC/Delco and the oil is changed every 3000 miles and is 5w 30 Havoline. Is this the infamous 'piston slap'? If so I guess that's fine and dandy. From what I've heard, piston slap is supposedly harmless to the engine/durability. I just wondered if it could be something else.

 

if its a clatter like a diesel then it is probably piston slap.

 

However, the 08's do have a problem with lifters that cause valve noise........

[crepitus]

just posted something up last week. mine does the same thing but never lasts more then a few seconds. check out this link.

 

http://www.gm-trucks.com/forums/index.php?...c=86186&hl=

[gnet158]

I have the iron block too but it never gets that cold here in CA. The manual states for cold weather use a synthic motor oil. Try that and see if it helps, it should since the noise goes away. I switched to Pennzoil Platinum syn at 1,350 miles, I have just under 4,000 on her now.

 

 

What’s the difference between the iron and aluminum block?

[bowserb]

most likely piston slap, many gm engines have this problem on startup........my buick century 3100 v6 also sounds like a diesel on startup many days........

[JNG3]

If it's p. slap then that's ok, BUT what would it be if it's NOT p. slap? What are the symptoms of the lifters/valve noise issue that MKelly mentioned, other then the obvious, noise. Does it do it all the time instead of just when cold?

[BlackSilver]

Once warmed up the clatter goes away.

 

Bummer!

[pwall]

Mine has a 'clatter' as well...but it doesn't go away.

 

 

 

 

Sorry, couldn't resist.

[JNG3]

Smart Alecks!

[Zembonez]

Smart Alecks!

YUP. That's us.

 

I'd try going to a 0W20 oil in Winter or at least a 5W20. It might help the noise.