Internal engine squeak
Thread Starter
Teching In
Joined: Dec 2018
Posts: 18
Likes: 1
Internal engine squeak I bought a 2005 Silverado 1500 that came with the 4.8/4l60e. The seller didn’t speak English and the title paperwork was a bit sketchy (signed over twice on the same duplicate title) but I made a lowball offer and he took it - $2k.
These are the initial problems that I saw: airbag light, CEL (misfiring on random cylinders, both banks lean), abs/brake light, and an oil leak.
This is what I’ve done so far: replaced front left airbag impact sensor, that fixed the airbag light. Replaced the abs module and front left wheel hub/abs sensor, that fixed the abs light. Fixed two vacuum leaks, that fixed the CEL.
At this point I changed the oil and found that it was running on very thick oil and was overfilled (about 1/2” above the full line). After an oil change to 5w30, the oil pressure was low on cold start, about 20 psi (confirmed with a real gauge). I pulled the pan, replaced the oil pump o ring and pan gasket which solved the low oil pressure. I’m now getting 45+ psi at cold start idle and towards the top of the gauge on the cluster at full throttle.
About a day after I replaced the oil pump o ring a rotational squeak developed that sounded like a belt or tensioner. I yanked the belts off to confirm that I didn’t get any oil on them, and the squeak remains, even when running without belts. The squeak is only present until ~3000 rpm at which point it disappears. After doing some research, I've come to the conclusion that it could be coming from a lifter. Does this seem like a likely scenario? The engine has definitely been replaced at some point (junkyard writing all over it). It is not a DOD/AFM engine, so likely a LM7 or LR4.
In my parts bin I have everything except a cam and lifters to fix this issue, if it is indeed a problem with a lifter. Is there something else I can look for to determine the issue? A stethoscope only revealed that it is near the top rear of the engine.
Please let me know if you need any additional information.
Thanks!
These are the initial problems that I saw: airbag light, CEL (misfiring on random cylinders, both banks lean), abs/brake light, and an oil leak.
This is what I’ve done so far: replaced front left airbag impact sensor, that fixed the airbag light. Replaced the abs module and front left wheel hub/abs sensor, that fixed the abs light. Fixed two vacuum leaks, that fixed the CEL.
At this point I changed the oil and found that it was running on very thick oil and was overfilled (about 1/2” above the full line). After an oil change to 5w30, the oil pressure was low on cold start, about 20 psi (confirmed with a real gauge). I pulled the pan, replaced the oil pump o ring and pan gasket which solved the low oil pressure. I’m now getting 45+ psi at cold start idle and towards the top of the gauge on the cluster at full throttle.
About a day after I replaced the oil pump o ring a rotational squeak developed that sounded like a belt or tensioner. I yanked the belts off to confirm that I didn’t get any oil on them, and the squeak remains, even when running without belts. The squeak is only present until ~3000 rpm at which point it disappears. After doing some research, I've come to the conclusion that it could be coming from a lifter. Does this seem like a likely scenario? The engine has definitely been replaced at some point (junkyard writing all over it). It is not a DOD/AFM engine, so likely a LM7 or LR4.
In my parts bin I have everything except a cam and lifters to fix this issue, if it is indeed a problem with a lifter. Is there something else I can look for to determine the issue? A stethoscope only revealed that it is near the top rear of the engine.
Please let me know if you need any additional information.
Thanks!
TECH Fanatic
Joined: Jan 2018
Posts: 1,250
Likes: 239
From: Dade City, Fl.
I bought a 2005 Silverado 1500 that came with the 4.8/4l60e. The seller didn’t speak English and the title paperwork was a bit sketchy (signed over twice on the same duplicate title) but I made a lowball offer and he took it - $2k.
These are the initial problems that I saw: airbag light, CEL (misfiring on random cylinders, both banks lean), abs/brake light, and an oil leak.
This is what I’ve done so far: replaced front left airbag impact sensor, that fixed the airbag light. Replaced the abs module and front left wheel hub/abs sensor, that fixed the abs light. Fixed two vacuum leaks, that fixed the CEL.
At this point I changed the oil and found that it was running on very thick oil and was overfilled (about 1/2” above the full line). After an oil change to 5w30, the oil pressure was low on cold start, about 20 psi (confirmed with a real gauge). I pulled the pan, replaced the oil pump o ring and pan gasket which solved the low oil pressure. I’m now getting 45+ psi at cold start idle and towards the top of the gauge on the cluster at full throttle.
About a day after I replaced the oil pump o ring a rotational squeak developed that sounded like a belt or tensioner. I yanked the belts off to confirm that I didn’t get any oil on them, and the squeak remains, even when running without belts. The squeak is only present until ~3000 rpm at which point it disappears. After doing some research, I've come to the conclusion that it could be coming from a lifter. Does this seem like a likely scenario? The engine has definitely been replaced at some point (junkyard writing all over it). It is not a DOD/AFM engine, so likely a LM7 or LR4.
In my parts bin I have everything except a cam and lifters to fix this issue, if it is indeed a problem with a lifter. Is there something else I can look for to determine the issue? A stethoscope only revealed that it is near the top rear of the engine.
Please let me know if you need any additional information.
Thanks!
These are the initial problems that I saw: airbag light, CEL (misfiring on random cylinders, both banks lean), abs/brake light, and an oil leak.
This is what I’ve done so far: replaced front left airbag impact sensor, that fixed the airbag light. Replaced the abs module and front left wheel hub/abs sensor, that fixed the abs light. Fixed two vacuum leaks, that fixed the CEL.
At this point I changed the oil and found that it was running on very thick oil and was overfilled (about 1/2” above the full line). After an oil change to 5w30, the oil pressure was low on cold start, about 20 psi (confirmed with a real gauge). I pulled the pan, replaced the oil pump o ring and pan gasket which solved the low oil pressure. I’m now getting 45+ psi at cold start idle and towards the top of the gauge on the cluster at full throttle.
About a day after I replaced the oil pump o ring a rotational squeak developed that sounded like a belt or tensioner. I yanked the belts off to confirm that I didn’t get any oil on them, and the squeak remains, even when running without belts. The squeak is only present until ~3000 rpm at which point it disappears. After doing some research, I've come to the conclusion that it could be coming from a lifter. Does this seem like a likely scenario? The engine has definitely been replaced at some point (junkyard writing all over it). It is not a DOD/AFM engine, so likely a LM7 or LR4.
In my parts bin I have everything except a cam and lifters to fix this issue, if it is indeed a problem with a lifter. Is there something else I can look for to determine the issue? A stethoscope only revealed that it is near the top rear of the engine.
Please let me know if you need any additional information.
Thanks!
Don't forget to replace the lifter buckets. I had the heads reworked before I reinstalled them also.
Thread Starter
Teching In
Joined: Dec 2018
Posts: 18
Likes: 1
Thanks for the sanity check, I just ordered lifters and buckets today - with a 3 week backorder. Since the heads are coming off I'll have the machine shop check them as well, I'd hate to have to pull them back off trying to save $100.
I'll report back with the results.
I'll report back with the results.
