What is this noise ? Knock or something else ?
Thread Starter
Teching In
Joined: Mar 2024
Posts: 2
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What is this noise ? Knock or something else ? Looking to diagnose this noise coming from what I assume is a 2000 LM7 5.3 Vortec, definitely a 5.3 Vortec just not sure of the specific model being LM7. It's in a 2000 Chevrolet SUV.
It had an overheating incident and was towed home due to the starter failing at the same time. Seller says water pump failed and caused the overheating but didn't check the thermostat. Starter was replaced, the engine was started, and this was the noise at start up... https://youtube.com/shorts/JWj25xIzg30?si=oct_SjwQUvGMRvm3
The seller thinks it's an engine knock, but it doesn't sound like a solid "knock" but rather a loose rattling faint knocking sound as if something spinning is loose and faintly knocking.
Seller doesn't know if the noise is a top end or bottom end noise, but you can definitely hear it from the top passenger side in the video.
Going to check things out and hear it in person this Sunday, but my anxiety won't make the wait easier lol...I need this vehicle as a family vehicle and for $1,000 I don't want to pass it up.
What do you guys think ?
It had an overheating incident and was towed home due to the starter failing at the same time. Seller says water pump failed and caused the overheating but didn't check the thermostat. Starter was replaced, the engine was started, and this was the noise at start up... https://youtube.com/shorts/JWj25xIzg30?si=oct_SjwQUvGMRvm3
The seller thinks it's an engine knock, but it doesn't sound like a solid "knock" but rather a loose rattling faint knocking sound as if something spinning is loose and faintly knocking.
Seller doesn't know if the noise is a top end or bottom end noise, but you can definitely hear it from the top passenger side in the video.
Going to check things out and hear it in person this Sunday, but my anxiety won't make the wait easier lol...I need this vehicle as a family vehicle and for $1,000 I don't want to pass it up.
What do you guys think ?
Well... worst case its a rod knock and you throw a $500 engine in it........
If it is a rod knocking its defiantly more than one lol...
Kinda sounds more like the fan is hitting something, but it does have the bottem end thud kinda sound to it, video is way to short of run time
If it is a rod knocking its defiantly more than one lol...
Kinda sounds more like the fan is hitting something, but it does have the bottem end thud kinda sound to it, video is way to short of run time
Thread Starter
Teching In
Joined: Mar 2024
Posts: 2
Likes: 0
Well... worst case its a rod knock and you throw a $500 engine in it........
If it is a rod knocking its defiantly more than one lol...
Kinda sounds more like the fan is hitting something, but it does have the bottem end thud kinda sound to it, video is way to short of run time
If it is a rod knocking its defiantly more than one lol...
Kinda sounds more like the fan is hitting something, but it does have the bottem end thud kinda sound to it, video is way to short of run time
Here is a video of it...
Figured if I did have to replace this LM7 motor, I could rebuild it and install it in my Monte Carlo...bright side of pulling and replacing.
