Tapping noise in the morning

[06 Taco]

I have an 06 Tahoe Z71 with 175,000 mile on it. Some mornings when I start the truck I hear a tapping noise that stops in and about a second or two, I think it's a lifter but I'm not 100% on that. I have always done regular oil changes at about 3000 miles. The truck does sit unused for about five months a year during the summer.
Could a lifter be failing or is it possibly weak or dirty? What would be the best way to determine where the noise is coming from? Is there a product that I can put in the motor to clean up the internals?
It's been a fantastic truck and I want to take care of it.

 

[OR VietVet]

What oil and filter do you use? When you say "start in the morning", I am assuming you mean after sitting overnight, correct? Just for grins, check the head of each exhaust manifold attaching bolt. They could be broke and not have fallen off. Can use a socket and ratchet or wrench, to check tension. If have a broken one, the noise you hear may be from that. But is likely, especially in cold enough weather or sitting overnight, a lifter bleeding down that pumps up immediately after a start.

 

[YukonRog]

Does the sound go away when your oil pressure gauge comes up? Hopefully to about 40 psi...

 

[nonickatall]

Can you do a video and upload it to YouTube?
Just from a description, hard to tell...

 

[06 Taco]

I have an 06 Tahoe Z71 with 175,000 mile on it. Some mornings when I start the truck I hear a tapping noise that stops in and about a second or two, I think it's a lifter but I'm not 100% on that. I have always done regular oil changes at about 3000 miles. The truck does sit unused for about five months a year during the summer.
Could a lifter be failing or is it possibly weak or dirty? What would be the best way to determine where the noise is coming from? Is there a product that I can put in the motor to clean up the internals?
It's been a fantastic truck and I want to take care of it.

I don't think it's the exhaust because the taping noise stops in less than two seconds but I will check the exhaust manifold out, that's easy enough. I think that I'd like find a method to pin point and correct the noise if possible. I think it's a lifter that is pumping up after an over night bleed down.

 

[06 Taco]

Does the sound go away when your oil pressure gauge comes up? Hopefully to about 40 psi...

The tapping stops in less than two seconds. Oil pressure has always been good at 40+ lbs. I will check and see how quickly it comes up in the morning.

 

[YukonRog]

The tapping stops in less than two seconds. Oil pressure has always been good at 40+ lbs. I will check and see how quickly it comes up in the morning.

I am just wondering if you see a correlation. Watch the oil pressure gauge when you start it. If it quiets down when the pressure comes up it's most likely a lifter. But there's also a chance a different, slightly thicker oil would work better. And lastly, your oil filter anti drain back valve may be bad allowing the oil to drain back.

 

[rockola1971]

Likely a lifter or lifters bleeding down. Immediately before next oil change (assuming you do your own). Drain off a quart and add a quart of ATF fluid and let sit idle for 30mins. DO NOT REV ENGINE AND DO NOT DRIVE VEHICLE WITH ATF IN THE OIL. Drain it all out and continue with your oil and filter change. See if that fixes it.

 

[B-train]

It definitely sounds like a lifter issue by the way you describe it. It could be due to a bad anti-drainback valve, or it could be some varnish buildup from years of use.

1. Have you ever had unexplainable coolant consumption? Water in oil can cause lifter noise, but it usually doesn't go away quickly
2. Replace oil and filter with good 5w-30 oil and a GM OE filter.
3. Try running 1/2 quart of ATF added to the oil for the last 500 miles before an oil change. The high detergents will help wash off any varnish residue and clean out the internals (I've done this for years on everything from the 90's to my 2017, is OK)

 

[iamdub]

The tapping stops in less than two seconds. Oil pressure has always been good at 40+ lbs. I will check and see how quickly it comes up in the morning.

I'm betting a lifter draining down. +1 to what @rockola1971 and @B-train said.

Next time it has sat overnight, when it should tick at that next startup, hold the accelerator to the floor and crank the engine for about 10 seconds. Holding the pedal keeps it from starting. Let it sit for a minute or two and repeat. Do this two or three times, preferably until you see a little pressure on the oil gauge. After that, release the pedal and start it as normal. Note any differences in ticking severity or endurance.