Good evening,

I could use some help trying to diagnose a problem for a friend. I am trying to determine what could be the cause of his starting problem. He informed me a few days ago that his truck would not start so I went to his place and told him to try and turn it over. All I heard was a loud clunk sound which sounded like the starter not turning over. So after searching this forum and locating the link telling me the tools I would need ( double extension, 13mm, etc very helpful by the way!!) the truck will still not turn over. I took off the starter (and that third bolt was a PITA!!) and took it to autozone and they tested the starter and it turned over without any issues.

So after that I am thinking that it could be his battery. Had them check that and it was good. Ok so then I see your truck has a starter relay on the firewall. So we replaced that, I had him try to start it. The truck tried but it and made some weird sound, almost like growling, and then went back to the clunk. At this point I am stumped on this one. I checked the positive battery cables for any corrosion and I didn’t see anything on the posts.

He just informed me that a week ago though when we had some snow, he tried switched the truck into 4WD but he said it didn’t switch over and his check engine light came on. He drove it around for a week, went to KFC, came back out the truck wouldn’t start. I don’t know if that would cause the truck to not start but figure I post it.

Sorry for the long post but figure I more info is better than none. Thank you for your help.

 

BTW it is a 98 Expy with 240K

 

Have you tried turning the engine by hand. Sounds like something mechanical in the engine could be binding it up. I would use a breaker bar and turn in it operating direction by the bolt at then end of the crankshaft. You should be able to turn it with a moderate amount of force.

I saw almost this same problem on a friends boat engine. He changed the starter and batteries and called me to help. I put a wrench on the end of the crank and couldn't turn it by hand. Turned out on it the cylinders were full of ocean water. Doubt you find that unless your friend has been driving in the surf but it does sound like a mechanical problem in the engine.

 

I think it would be a good idea to make sure the engine can be turned over by hand first. I doubt it would freeze up without warning after just being driven but you never know.

If you can turn it over by hand I think I would look more closely at the battery cables. Make sure you are getting full power to the starter motor, and make sure the ground is solid. Over time cables can develop internal corrosion and shorts you can not see.

 

Assuming the starter is installed, remove the serpentine belt and see if it cranks. If it does, one of the accessories has seized and is locking the motor up when the serpentine belt is installed. I had my compressor pulley do this to me a couple of years ago.