Helluva banging noise and won't turn over

[GentleGiant]

Sounds bad to me. Here's the story:

My 1984 M1008 sat in the barn over the winter, and last week I finished changing my glow plugs (many thanks to this forum for helping me with that). The truck started perfectly. I warmed it up and changed the oil. Then I did a few runs to pick up some firewood - truck started perfectly many times. I drove it about 40 miles in this process.

Next morning I went to start it and when I turned the key it sounded like about 4 guys with a hammer in each hand were under the hood banging on the engine block. My wife looked under the hood and said that the fan was just shaking in its place, not spinning 'round. I stopped any effort to try starting it.

Morning after that, I decided to try banging on the starter to see if that would loosen something up. When I tried to turn the key, nothing. Testing revealed that one of the batteries was flat dead.

I think the battery is a coincidence, but what is that banging sound! My mechanic thinks maybe its a busted harmonic balancer...

What do you all think, and how do I determine the problem?

Thanks fellas.

 

[998Junkie]

Does the crank rotate when you attempt to start it? A dead battery could be the issue. Try a new battery. I'm thinking not enough juice to kick the starter up right and the banging is a result.

With the required amperage, I'm thinking the starter will engage and you will hear the engine crank normally.

 

[rickf]

Sounds like a broken crankshaft. They are famous for breaking behind Number 2 rod journal.

 

[GentleGiant]

Thank you 998Junkie and RickF for your quick replies.

I was tending to think it was probably something like the crankshaft, but I thought I'd try the bad battery idea first. I charged up the battery that is in there (probably does need to be replaced, but it took a charge), and tried starting it. VROOM! Started right up just perfect.

Thank you both very much. I am very grateful for this forum.

 

[rsh4364]

Thanks to you ,always nice to to see a solution to a problem.

 

[998Junkie]

After a few issues with my CUCV and the absolute depth of knowledge here I now tend to look for the simpler things before I start to panic about major repairs. The best one I can remember is no tail lights the fuses looked good and I started to panic about all the things I would need to trouble shoot. Search here turned up that the fuse is bad, but it might look fine. Sure enough the fuse had melted at the base. A little cleanup and a new fuse and I was good to go.

I'm glad it was a easy fix. Now is the battery bad or do you have a drain?

 

[rickf]

Just as an aside, Do NOT bang on the starter unless you plan on replacing it! That worked 30 years ago when the magnets were ferrous magnets but now they are ceramic rare earth magnets and will break very easily if you hammer on them.

 

[GentleGiant]

Thanks, RickF,

Good detail to know!! I didn't hit it very hard, but won't do it again.

 

[cpf240]

I'm guessing that the banging noise was relay / solenoid chatter when trying to turn over with the weak batteries.

 

[Csm Davis]

Just as an aside, Do NOT bang on the starter unless you plan on replacing it! That worked 30 years ago when the magnets were ferrous magnets but now they are ceramic rare earth magnets and will break very easily if you hammer on them.

Okay got to be the smart butt the trucks are 30 years old. So wouldn't it still work?

 

[rickf]

CSM, Technically yes, IF it were the original from the factory starter and even then they were changing over at that time. I keep forgetting that 30 years ago is 1985! That is depressing, I am getting old. I have never heard an engine "Banging" due to a low battery, Solenoid chatter or not. If there is not enough power to pull in the solenoid then there certainly not enough to engage the starter. Time will tell on this one but I think there is more to come.

 

[Csm Davis]

CSM, Technically yes, IF it were the original from the factory starter and even then they were changing over at that time. I keep forgetting that 30 years ago is 1985! That is depressing, I am getting old. I have never heard an engine "Banging" due to a low battery, Solenoid chatter or not. If there is not enough power to pull in the solenoid then there certainly not enough to engage the starter. Time will tell on this one but I think there is more to come.

Just had to rub that in bud.

 

[nyoffroad]

C I have never heard an engine "Banging" due to a low battery, Solenoid chatter or not. If there is not enough power to pull in the solenoid then there certainly not enough to engage the starter. Time will tell on this one but I think there is more to come.

My thoughts also! I"d spend a few minutes crawling around and check the starter bolts, fan mounting and belt tension. I'd also give the damper a good looking over.