cam and lifters

I'm not near my service manual and haven't had the valve covers off my 99

Brian

Check your coolant level. If it's down, then check very carefully for coolant on top of engine (Q-tip on a stick). Look at the cross-over exhaust underneath while the motor's running. Is there coolant dripping down the back side? If any of these are true, then your intake manifold is leaking and you might be getting coolant into the oil and/or leaking into the lifter valley from above. Don't ask me how I know ...I'm 19k into a second intake gasket and it's leaking again, and the lifters are making noise again.

Brian

hydraulic lifters and it comes and goes

loud when cold goes away warm some times and sometimes not

that is a hydraulic roller cam in that block, and yes you can replace a individual lifter but i would replace the entire set. you can try adjusting the lifters but chances are the lifters are collapsing from age. Roller lifters are heavier than a flat tappet lifter and require more spring pressure in order to keep the lifters in contact with the cam lobes at high rpm's, the increased spring pressure is hard on the lifters and causes them to collapse over time. You don't have to change the cam with the lifters (unless you want to). vortec heads wont support more than .460" lift w/o cutting the seats and changing the springs as well as elongating the push-rod guide holes. Vortec heads also require self aligning rockers or guide plates (your choice).

Thanks for the info. I haven't taken it apart yet so I couldn't say 1 way or other.

Funny thing Mad Dog, I started truck this morning and no noise. Can you beat that? Sometimes it clatters and sometimes it's quiet.

You know I'm not a big fan of magic additives to put in engines. But a lot of people have sworn that Rislone can help clean varnish from engine parts such as lifters. I'm not saying that's why it's noisy, but I don't think that you've stated the mileage on the motor. So it's possible that the lifters are dirty and not worn out. Do you change the oil frequently?

Brian

Mileage is about 84K, and yes I have been changing the oil less than 1K miles each time

I'm not big on additives either but I did try Marvel Mystery Oil last winter and it did not help.