Express, Savana & G-Series Vans Offered in both a full size van, or a large box truck, the Express is the modern GM workhorse.

Chevrolet Express
Platform: GMT Van

is this 4.3 motor done?

Thread Tools
 
Search this Thread
 
Old Sep 19, 2018 | 2:50 PM
  #1  
exasperito's Avatar
Thread Starter
CF Beginner
 
Joined: Sep 2018
Posts: 5
Likes: 0
Default is this 4.3 motor done?

Everything was fine until I had a sudden loss of power on a mountain road. I continued to drive to town, where it slowly died. It started up the morning after being towed home, but the motor makes a terrible noise. I'm worried it's the crankshaft bearings. I unplugged the spark solenoid so I could hear what it sounds like turning over without combustion. It sounds normal. Wouldn't the crankshaft bearings be noisy even being turned by the starter? I took off the serpentine belt to check all pulleys for grinding or resistance, and found none. This noise is something awful, especially from inside the van with the cover off It sounds like the motor has negligible lubrication. It is definitely not the sound of a starter solenoid failing to disengage.

Any ideas? Thanks!

Last edited by exasperito; Sep 19, 2018 at 2:52 PM. Reason: added detail
Reply
Old Sep 19, 2018 | 2:55 PM
  #2  
kevinkpk's Avatar
CF Monarch
10 Year Member
Liked
 
Joined: Jul 2011
Posts: 5,920
Likes: 140
From: kevinkpk
Default

If you can post a video, would be easier to try and diagnose. How many miles?
Reply
Old Sep 19, 2018 | 2:57 PM
  #3  
oldchevy's Avatar
CF Monarch
10 Year Member
Liked
 
Joined: Apr 2012
Posts: 6,216
Likes: 438
From: Miami, FL.
Default

What does the oil look like? Did it overheat? What is the oil pressure?
Reply
Old Sep 19, 2018 | 4:09 PM
  #4  
geo1's Avatar
CF Senior Member
 
Joined: Aug 2018
Posts: 357
Likes: 2
From: Adirondacks,ny
Default

Continued to drive?it's toast,you can't drive it with spark disconnected,so the test is start it,I'm thinking you know the results,stuff happens,time for a project
Reply
Old Sep 19, 2018 | 4:35 PM
  #5  
exasperito's Avatar
Thread Starter
CF Beginner
 
Joined: Sep 2018
Posts: 5
Likes: 0
Default

Originally Posted by kevinkpk
If you can post a video, would be easier to try and diagnose. How many miles?
Good point re: video! I'm grateful for your responses, not used to this level of engagement in auto diagnosis forums!

Originally Posted by oldchevy
What does the oil look like? Did it overheat? What is the oil pressure?
The oil looks fine. I initially suspected head gasket failure but no signs of coolant & oil mixing nor of exhaust in coolant. Good point re: oil pressure, not set up here to test it. I did use OBD reader to check for codes and there were none despite that the service engine light had come on.

Originally Posted by geo1
Continued to drive?it's toast,you can't drive it with spark disconnected,so the test is start it,I'm thinking you know the results,stuff happens,time for a project
I never drove it w spark solenoid disconnected, i just turned the engine over while parked so i could listen for the noise with pistons moving but without it running.

Last edited by exasperito; Sep 19, 2018 at 4:41 PM. Reason: i had overlooked question
Reply
Old Sep 19, 2018 | 4:42 PM
  #6  
geo1's Avatar
CF Senior Member
 
Joined: Aug 2018
Posts: 357
Likes: 2
From: Adirondacks,ny
Default

Yep,no load on pistons,no knock,oil looks ok?oil pump failure,I hope I am wrong,just be prepared
Reply
Old Sep 19, 2018 | 4:48 PM
  #7  
exasperito's Avatar
Thread Starter
CF Beginner
 
Joined: Sep 2018
Posts: 5
Likes: 0
Default

Originally Posted by geo1
Yep,no load on pistons,no knock,oil looks ok?oil pump failure,I hope I am wrong,just be prepared
Wouldn't the oil pump failure have manifested as engine seizure that first day? also what of the extremely sudden loss of power just as I was about to accelerate to pass another motorist? Thank you for your input!
Reply
Old Sep 19, 2018 | 4:55 PM
  #8  
geo1's Avatar
CF Senior Member
 
Joined: Aug 2018
Posts: 357
Likes: 2
From: Adirondacks,ny
Default

When they cool off,movement happens,and about to pass another vehicle?you mentioned,you drove it till it died,that's heat and now you have"awful noise",oil is o.k.,fire it up,idle,no revs,listen,down low,yikes
Reply
Old Sep 19, 2018 | 5:03 PM
  #9  
exasperito's Avatar
Thread Starter
CF Beginner
 
Joined: Sep 2018
Posts: 5
Likes: 0
Default

Originally Posted by geo1
When they cool off,movement happens,and about to pass another vehicle?you mentioned,you drove it till it died,that's heat and now you have"awful noise",oil is o.k.,fire it up,idle,no revs,listen,down low,yikes
please clarify why you mean by no revs, listen down low THANKS
Reply
Old Sep 19, 2018 | 5:12 PM
  #10  
geo1's Avatar
CF Senior Member
 
Joined: Aug 2018
Posts: 357
Likes: 2
From: Adirondacks,ny
Default

Listen for rattle,if it's outside the motor,no harm done,follow the sound,internally,knocking,you can't fix that with a small part
Reply



All times are GMT -5. The time now is 11:30 AM.