Help, seize when cranking on cold starts

[Mossback]

1996 K1500 5.7l

Odd symptoms:
Cranks super slow and basically seizes up. Stop, retry and it will crank over one or two times before it seizes up and the starter clicks. After many attempts holding the key to crank it will eventually start cranking fast enough to fire. Once the truck is warm it cranks and fires perfectly! Over and over again.

brand new battery, good terminals, connections and grounds. Tried replacing the starter with a new gear reduction unit. Did the exact-same thing.. so I put my direct drive unit back in concluding that the starter was good.

I only drive this truck a few times a month. It had kinda displayed these symptoms before but it wasn’t bad enough that it wouldn’t start.
Im confused at what is happening?
Out of time? Voltage drop?
anyone ever dealt with this?

 

[GoToGuy]

Have checked the battery on the cold morning before start?

 

[Mossback]

I haven’t checked volts. But it will even do it when its warm out but the truck isn’t warmed up. Does the same thing with jumper cables hooked up to a running car. Although that helps a little bit, still slow hard crank.

 

[Orpedcrow]

Pull the serpentine belt off and check the accessories. You should be able to turn everything by hand. Had a Buick the other day that showed bad starter symptoms, and it was a seized a/c compressor clutch.

 

[Mossback]

Good idea! Thanks

 

[Schurkey]

I had a CS130 alternator with the "usual" rear bearing failure. Shut the truck off to get gasoline, engine wouldn't crank when I wanted to drive away. Had to pull the belt to drive the few blocks to the parts-store.

Otherwise, you NEED to do voltmeter testing. Battery no-load volts, battery voltage while cranking, and voltage-drop testing on both the + and the - sides of the starter motor.

VD testing instructions attached.

IF (big IF) the voltage testing has adequate results...what are the chances that the engine is getting coolant in the cylinders, and "nearly" hydro-locking?

 

[Mossback]

no seized pulleys..

 

[Mossback]

Will bring my volt meter home tomorrow for VD test

 

[Mossback]

I sure hope it’s not hydro locking with coolant! Runs good once it starts and doesn’t blow a ton of steam out the exhaust

 

[Vikingdude]

Sounds like a poor electrical connection or component somewhere. Checked/cleaned your grounds recently? Check battery voltage as recommended.