Tapping sound in a 2002 Silverado

I have a 2002 Chevy pickup, V8. Recently it has a tapping sound early in the morning which has been going away as the engine warms up. The frequency varies with engine speed. It has also been requiring coolent refiles a couple of times a month. I took it to the Chevy dealer and they replaced a water pump gasket. They said the tapping was hydraulic valves and was nothing to worry about.

Can anybody confirm the idea of the lifters?

My 2001 Silverado with a 5.3 engine does the same thing - and it’s because the hydraulic lifters are a bit worn (156,000 miles on mine) and don’t hold the oil overnight. As soon as they fill with oil again, the noise goes away. I have also been told not to worry. If the noise bothers you, the only cure is to replace the lifters - I have no idea how much that costs.

I agree with zone. The only thing I will add is to make sure you are getting a quality oil filter designed for your vehicle.

OK, thanks guys. Nice to confirm they are getting it right.

I think its more likely piston slap causing the noise, and the loss of antifreeze is most likely a intake manifold gasket.

We’ve had this discussion with regard to my Tahoe. It’s lifters. Make sure your oil filter has an anti-drainback valve. In the winter if you live in the northern half of the country, be sure to use synthetic oil, as it will pump back up faster when it’s cold.

Oh yes, the intake manifold gasket is a famous problem of these engines. It is moderately expensive to fix, but you should do so, since the coolant might get into your oil.