Tapping Sound from 2004 GC 4.7l Engine

Most engines now use hydraulic lifters and they can leak a little, this causes space between then lifter and the push rod. This results in a tapping noise that goes away when they get warm or fill back up.

What's That Ticking Sound Coming From Your Car's Engine?

www.popularmechanics.com/.../whats-that-ticking-sound-coming-from-...

Apr 18, 2014 - My engine has developed a strange ticking sound. Its whisper-quiet before an oil change, and then makes a loud tapping after a new filter and ...

Engine Tapping - Auto Repair Help

www.auto-repair-help.com/auto_diagnostics/engine_tapping.php

ENGINE MAKES TAPPING NOISE WHEN STARTED by Mark Davidson. SYMPTOM SUMMARY The engine emits a tapping noise on start up. The noise may ...

Engine Ticking Clunking Noise - Repair - YouTube

? 9:37
https://www.youtube.com/watch?v=ilDtnJi_BS0
Mar 15, 2013 - Uploaded by knurlgnar24
One of my vehicles started making a rather disturbing sound so I went to investigate and to hopefully fix it.

My first guess would be a failing valve lifter. They can become weak with age and not able to hold oil pressure.
Especially in an engine with that many miles on the clock.
If the noise is constant you may be able to find out which cylinder by running a compression test. maybe.

Hi Joko,

What you are describing is a failure of a main circuit. The first thing you should check is yo make sure that your battery is in good condition and that the cables are clean and tight. Let me know if yu find anything wrong there. Then there may be another main circuit problem. Check all of the fuses in your fuse block in the engine compartment. If any of these fuses are blown, it will usually cause several things to not work. If you find any fuses blown, DON'T REPLACE IT YET. Let me know WHICH fuse is blown and I can help you find out why it blew so you can get the problem fixed.

Get back to me on this and we will continue.

-Dave (dttech)

The tapping is normal at start up, and is caused by lack of oil at the top of engine. The sound goes away within the time frame you stated (30-40 seconds). You have nothing to worry about.

We have the same tapping sound on our 2003 Envoy six cylinder engine. I believe the sound is coming from the radiator fan clutch assembly. When the engine reaches its operating temperature and the fan clutch engages, the tapping sound goes away.

it sounds like your timing chain needs replacing. Better get it seem to quick in case of trouble if it breaks.

could be rod with that amount of miles

sounds like the lifters losed prime! here is a little trick that ive learned add a half off quirt off transmission fluid to the oil to prime the lifter

Check engine oil level and confirm engine lubrication. Could be the tappets clicking due to not enough oil up there. Does noise go down as engine heats up?