I have a 1991 S-10 4.3L 4WD with 58000 miles that is burning up starters! It has 7 (going on 8) starters in its lifetime! The last time that my starter bit the dust, my mechanic installed the new one, drove the truck out of the garage and the thing wouldn’t start again! I know that some of these rebuilt units can be bad but no way have I gotten 7 of them! My thoughts are that I have something upstream of the starter that is allowing too much voltage and/or current to the solenoid thereby causing premature failure. Anyone ever heard of this or have any ideas?
I also forgot to mention that my mechanic suspected the ignition switch. He said that, after failure, the starter was still seeing 12V at measured at the solenoid.
We need to do a “autopsy”(find out why they failed)on these starters.
Are you shimming the starters correctly?
Have you ever measured the starter draw on any of these starters?
Has a inspection of the flywheel been performed? results?
Is it always a solenoid failure as you indicate?
Thanks for the reply!
I’m not sure about the first starter (failed when my grandfather owned the truck) but the remaining starters have all apparently been solenoid failures. Starter works before installation, fails in the truck, and (at least the last three) have definitely not worked when removed after failure. I did not do the install or testing myself but I fully trust my mechanic - he’s done honest work for my family for years. Luckily, these last 4 have all been under warranty so parts/labor are free for me 
Sounds like I now have a couple of questions to ask my mechanic for this go-around! About the shims and flywheel questions, is this to rule-out a sticky flywheel or improperly aligned starter that would possibly cause the starter to burn out while trying to engage the flywheel?
Thanks a bunch!
What happens when it fails? Noise? Has anyone taken a good look at the flywheel?
If your mechanic is still measuriing 12 volts at the starter asembly when the engine is running that means the solenoid is energized and the starter is still connected to and being spun by the flywheel. This will sbsolutely kill a starter.
Your mechanic is on the right track IMHO.
Does your car require cranking more than 2 seconds to start? I am wondering if you have to crank it for 15 seconds to start that could be a reason for premature failure.
I had a 91 blazer 4.3liter do the same thing. I’d replace the starter every couple of years. I would try a starter from the dealer to other parts places sround. I think its close to the exhaust manifold,witch it is. It’s burning them out. Try putting a shield around the top of the starter and solenoid. Great truck otherwise. I did the lifetime warranty thing too amd its not to hard to replace. yes sometimes a rebuilt one is bad from the start
You did not get 7 bad starters so you’re correct there.
Either the starter is not shimmed correctly and the flywheel/flexplate is remaining engaged with the starter drive teeth or there’s an electrical glitch that is causing the starter solenoid to remain activated.
The former can sometimes be determined by listening to the starter when the engine is cranked over.
The latter can be determined by placing an inductive ammeter on the positive battery cable and making sure that current is not being drawn when the engine is running.
Just curious. Has the engine or transmission ever been changed out in this vehicle?
A '91 with only 58k miles?
And in retrospect I should have asked if the starter solenoid makes a click sound when the engine suffers a no-start?
Nope. It usually starts right away (or not at all when the starter fails).
Good point but it doesn’t explain why I’ve now had 3 starters in the last month. Especially the one starter that was installed then driven out of the garage with subsequent failure. Also, we actually did purchase a new starter from the dealer for this last go-around to check if it is a brand issue.
I’ll start from the bottom, up…
The solenoid does click when the no-start occurs.
58K miles - original engine and tranny. It was my grandfather’s truck for 5 years and mine for the last 3. I generally take the bus/train to work so I don’t have to drive much
What I’m thinking now is that I may do have a faulty ignition switch. Something that is randomly staying on and allowing current to be drawn thus killing my solenoid. I’ll ask my mechanic to try the ammeter after he gets the thing going again and maybe to have multiple test starts.
Thanks a bunch!
also thanks to all the great replies on here! some really great ideas!