Bad knock out of nowhere! Please help

[Basshead21]

I have a 2010 Tahoe LT Z71. 165576 miles on it. This morning everything was normal then get halfway to work and it’s knocking ridiculously. I checked oil level and pressure and they are good.. any help is extremely appreciated! Thank you.

 

[thompsoj22]

Not much to go on here Cody, More description? One of those handy cell phone recordings?

 

[swathdiver]

I have a 2010 Tahoe LT Z71. 165576 miles on it. This morning everything was normal then get halfway to work and it’s knocking ridiculously. I checked oil level and pressure and they are good.. any help is extremely appreciated! Thank you.

Depends on where the knock is Cody. If up top, it's likely a collapsed AFM lifter. This repair can be done at home over a weekend for someone not too familiar with wrenching or in just a few hours by a pro.

 

[Basshead21]

Sounds more at the bottom. It’s pretty crazy it was fine this morning and then out of nowhere it was loud.

 

[swathdiver]

Sounds more at the bottom. It’s pretty crazy it was fine this morning and then out of nowhere it was loud.

Well, it happens, kinda soon though. Get a long extension or breaker bar or mechanics stethoscope and probe around until you find where it is. If it's a rod bearing, you'll need to rebuild the short block or replace the motor.

 

[Basshead21]

Not much to go on here Cody, More description? One of those handy cell phone recordings?

Well, it happens, kinda soon though. Get a long extension or breaker bar or mechanics stethoscope and probe around until you find where it is. If it's a rod bearing, you'll need to rebuild the short block or replace the motor.

that’s what I was afraid of . Thank you.

 

[wjburken]

I have a 2010 Tahoe LT Z71. 165576 miles on it. This morning everything was normal then get halfway to work and it’s knocking ridiculously. I checked oil level and pressure and they are good.. any help is extremely appreciated! Thank you.

Welcome to the forum. Wish it was under better

Does the noise change with engine speed? Did the Service Engine Light come on? I am assuming it is more of a tapping sound as opposed to a squeaking sound.

Agree that a video with sound would be nice.

The first thing that comes to mind is you have a lifter that has failed. This is a common issue with these motors. Another possibility is a broken valve spring which is also known to happen, but is not as common as the lifter failure. I am assuming that you have AFM/DOD still active on your vehicle where it switches from V8 and V4 mode.

How comfortable are you with working on cars?

 

[Basshead21]

Welcome to the forum. Wish it was under better

Does the noise change with engine speed? Did the Service Engine Light come on? I am assuming it is more of a tapping sound as opposed to a squeaking sound.

Agree that a video with sound would be nice.

The first thing that comes to mind is you have a lifter that has failed. This is a common issue with these motors. Another possibility is a broken valve spring which is also known to happen, but is not as common as the lifter failure. I am assuming that you have AFM/DOD still active on your vehicle where it switches from V8 and V4 mode.

How comfortable are you with working on cars?

I’m trying to upload the 13 sec video tats to big.

 

[Basshead21]

Welcome to the forum. Wish it was under better

Does the noise change with engine speed? Did the Service Engine Light come on? I am assuming it is more of a tapping sound as opposed to a squeaking sound.

Agree that a video with sound would be nice.

The first thing that comes to mind is you have a lifter that has failed. This is a common issue with these motors. Another possibility is a broken valve spring which is also known to happen, but is not as common as the lifter failure. I am assuming that you have AFM/DOD still active on your vehicle where it switches from V8 and V4 mode.

How comfortable are you with working on cars?

With speed it’s faster and no check engine light. And yes I do have that AFM/DOD. I believe I could do it.

 

[pwtr02ss]

Sounds more at the bottom. It’s pretty crazy it was fine this morning and then out of nowhere it was loud.

A lifter sounds like a rod knock. I would bet on that if your oil pressure is good.