Squealing Starter

Replaced a starter in my sons 89 blazer s/10 and it squeals when he starts it up, when he releases the key, the engine runs fine, it is not like the starter is locked in the out position. It only squeals when he first starts the engine.

Any thoughts...Thanks

Got all of your parts and shims back in? A missing shim or a slight mis-alignment of the starter will cause it to squeal like a pig when the teeth of the starter pinion are not quite meshing with the fly-wheel. Re-check your work, make sure that all of the parts you took out went back in. Baring that - take it to a shop and let the pro's check it.

It will eat your fly-wheel if given enough time - leading to an even bigger shop bill if you do not have a hoist to get that motor out and replace a toothless flywheel. ;)

Got all of your parts and shims back in? A missing shim or a slight mis-alignment of the starter will cause it to squeal like a pig when the teeth of the starter pinion are not quite meshing with the fly-wheel. Re-check your work, make sure that all of the parts you took out went back in. Baring that - take it to a shop and let the pro's check it.

It will eat your fly-wheel if given enough time - leading to an even bigger shop bill if you do not have a hoist to get that motor out and replace a toothless fly-wheel. ;)

Thanks for the reply, the new starter came with shims, acually I didn't realize what they were, I'll take your advice and check the alignment aout and maybe add a shim at a time.

Thanks for the advice, and yea we'll do it right away don't need a shop bill.

Yip, you are not shimmed properly.

Happened to me and the noise comes from the starter gear only clipping the top of the teeth on the flywheel.

Fix it quick or you will loose 5 teeth off of your flywheel like I did.

Along with the 3 shims there was a pin about an 1/8" in diameter and about 3 " long. Have any idea what that is for.

Along with the 3 shims there was a pin about an 1/8" in diameter and about 3 " long. Have any idea what that is for.

You have me there - but get this;

I will be working on my starter on Thursday. *sigh* At 133K miles, it is starting to loose its torsion bar. (Spins, but does not engage the flywheel) It will get a series of "false starts" where the motor turns, but does not engage the flywheel. Usually by the third turn of the key, she'll catch and fire. When I swap it out, I will tell you for certain what that pin is for. (If there is one on my truck too - it's an older OBD-1.5 '95 with VIN "W" 4.3 CPI) I am currently waiting around for a factory new Bosch replacement to be shipped in. If I find and figure it out, I will post back. Hang tight man!

Awesome...I look forward to a report. Fortunately my son is driving his brothers car until then so the one with the starter problem is sidelined til Saturday.

***Newsflash***

Okay, it was quite a bit of work, but I got that starter swapped on my truck. It does not start so much as rumble off the launch-pad now. *Muahahahaaaa* Okay... I too got the strange, little 1/8" x 4" piece of steel bar in the bottom of the box. Took a few phone calls, and managed to find the same answer every time I called. The short answer:

It's a testing/adjustment tool to check tooth clearance on a fresh install of a starter motor & flywheel.

The long answer:

This tool is used to push the actuating rod of the solenoid forward into it's engaged position. When you first match up a new motor and flywheel, this is used to make sure that the teeth of both match up by pushing it through a small hole in the back of the solenoid. If it isn't, shims are added/deleted to adjust the preliminary fit. Usually a good eye and experience using this tool will get you a starter and flywheel replacement done without chewing up the teeth on the initial test run. Once the gears are meshing properly with just a *tiny* amount of play - you then test start the truck after hooking in your solenoid wire *only*. So you need an assistant. When they turn the key to the start position, the solenoid will push forward and mesh with the flywheel. When released, it should cleanly disengage.

Then you hook up your battery cable and test start - listening for whining, grinding, or a slow, halting start. You then add or delete shims as needed to correct the clearance and silence that motor up. Mine was a *bitch* simply because it was in a very tightly packed 4x4 and a lot of stuff had to be dismantled and moved aside. I had no shims on the old motor, so I just bolted this one up. I poked the little steel bar through the back of the solenoid housing and sure 'nuff, everything matched well. Hooked it all up and made it snug, and test fired. Vroom, baby! I then closed her up, tightened everything to spec and got a local mechanic buddy to verify my work. He gave it the thumbs up - I tipped him a few bucks for his time. Mystery solved!

I agree about he tight working area, mine is on a 4x4 too and it was unbelieveable. They gave a little peek hole area from the top just enough to force your hand down through but no way to work on from up top..

After saying a few choice words for American Car engineers, I was able to rotate the starter around enough to get to the wires.

Thanks for replying and letting me know about the pin, this forum is great.

Now I have a couple of more questions for you:

When you say just the soleniod wire is that the wire that fastens up with the bigger red cable from the battery? I had three wires to fasten, which one do I not fasten when I test the engagement?

And secondly, I got thinking about hte shims and since the starter is mounted on the bottom of the flywheel wouldn't he shims only be used if the starter didn't disengage, meaning move the bendix farther away from the flywheel? I am wondering if I just have to maybe loosen up the mounting bolts and "twist" the starter a littel closer into the flywheel? I will try the pin alignment tool though.

Thanks again...

Ooooh, you have a three-wire starter. Mine was only a two wire. The solenoid wires are the much thinner, skinnier ones. When you turn your key to "start" all the ignition switch does is close a relay. The relay energizes the solenoid. When they plunger and pinion gear are thrown forward by this action, it also closes a switch (A heavy duty one at that!) inside the starter that then draws power down from the thick battery cable to start the engine. So just test fire the starter with the two, thin wires in place to check for proper solenoid and gear engagement.

The shims are there to make a pad that can be adjusted so the starter pinion gear meshing directly in-line with the flywheel. No matter how well you shim, there is going to always be just a little bit of play so the teeth can cleanly slip in and out from between one another. Too close of a gap (Not enough shims) will make the teeth of the starter clash with not only the flywheel teeth, but may only allow partial engaging. This usually tears up both the starter and the flywheel, making a grinding noise and a squealing noise.

Too many shims, and the starter only catches on the very edge of the flywheel teeth. Though it engages fully, you will hear a squeal when the engine kicks over. This will ruin the flywheel in short order. If by adding back in the shims you already had, and the noise persists, I would blame the starter. Sometimes a part can get into the wrong box, or worse yet, something was so badly blown out of spec when rebuilt, it's not suited for starting a fist fight. ;)

One of the reasons why I *never* buy cheap on a starter - to me on my Blazer project, it was worth the 3 day wait and the extra $60 to get one sealed in the box from Bosch. No headaches. Lifetime warranty. Prevents male pattern baldness. Rainbows and butterflies come out of every A/C vent... *j/k* Etc. Etc.

Best advice I can give right now it to just get your old shim pads back un in between your block and starter and see if it works properly. They usually rebuild to factory, OEM specifications. If it still makes this terrible noise, drop and swap with your parts dealer on another one, explaining the situation. Have your reciept in your back pocket as proof of sale. Good luck, and I will try and watch this thread over the weekend - I am going to be busy. *sigh*

Ooooh, you have a three-wire starter. Mine was only a two wire. The solenoid wires are the much thinner, skinnier ones. When you turn your key to "start" all the ignition switch does is close a relay. The relay energizes the solenoid. When they plunger and pinion gear are thrown forward by this action, it also closes a switch (A heavy duty one at that!) inside the starter that then draws power down from the thick battery cable to start the engine. So just test fire the starter with the two, thin wires in place to check for proper solenoid and gear engagement.

The shims are there to make a pad that can be adjusted so the starter pinion gear meshing directly in-line with the flywheel. No matter how well you shim, there is going to always be just a little bit of play so the teeth can cleanly slip in and out from between one another. Too close of a gap (Not enough shims) will make the teeth of the starter clash with not only the flywheel teeth, but may only allow partial engaging. This usually tears up both the starter and the flywheel, making a grinding noise and a squealing noise.

Too many shims, and the starter only catches on the very edge of the flywheel teeth. Though it engages fully, you will hear a squeal when the engine kicks over. This will ruin the flywheel in short order. If by adding back in the shims you already had, and the noise persists, I would blame the starter. Sometimes a part can get into the wrong box, or worse yet, something was so badly blown out of spec when rebuilt, it's not suited for starting a fist fight. ;)

One of the reasons why I *never* buy cheap on a starter - to me on my Blazer project, it was worth the 3 day wait and the extra $60 to get one sealed in the box from Bosch. No headaches. Lifetime warranty. Prevents male pattern baldness. Rainbows and butterflies come out of every A/C vent... *j/k* Etc. Etc.

Best advice I can give right now it to just get your old shim pads back un in between your block and starter and see if it works properly. They usually rebuild to factory, OEM specifications. If it still makes this terrible noise, drop and swap with your parts dealer on another one, explaining the situation. Have your reciept in your back pocket as proof of sale. Good luck, and I will try and watch this thread over the weekend - I am going to be busy. *sigh*

Well I got back under it on Saturday, I added one shim and bumped the starter., it sounded better but still had a slight squeal. I added a second shim and got it sounded good.

It stilll seems very sensitive to keeping the key turned on any to long once it turns over. If you just bump the key and release it it sounds fine but if you keep the key turned over for any period of time after the engine turns over she squeals.

By the way my original starter did not have any shims and I still could not see where I could use the pin that came in the box.

Thanks for your help...

I would go get another starter.

It should be practically plug and play.

Or just get your own rebuilt. You knew it fit before no problems.

Well I don't have my old one any more I turned it in to get the core deposit. But maybe I will see how well auto zone stands behind the product and see if I can exchange it.

Do you know if they machine the mounting surface when the recondition? If I didn't take nay shims out originally should I have to put any in?

I didn't.

Just make sure you got the EXACT starter for your year and not for the full size blazer.

Agreed, trade it out because there sounds like there is something wrong with that starter. If you did not have shims in there before, you will not need them now. And likewise, if you had shims before, put them back in. Mine didn't have any shims. It was a direct, bolt in replacement, however I did have to state to the the lady I spoke to at the counter a few times just which type of engine I had, as their computer only really made one distinction on the 4.3 liter engines:

Horizontal rotor cap
Vertical rotor cap

See if you can read over the sales clerk's shoulder and point out the options that do apply to your truck and model year. That is the easiest way for them to match up the right parts even if it seems completely unrelated.

I am having a similar problem, a grinding noise when starting my 1990 Chevy Silverado. If I turn the ignition to "start" even momentarily too long, it makes a real grinding, squealing racket. The starter was replaced with a 5 year warranty higher quality Bosch unit in the fall of 2003. The new starter seemed to work fine except for an occasional whirring noise on failed starts where it took a few seconds for the starter motor to come to a stop. On more than a few occasions I have tried a restart before the starter came to a stop and nailed the flywheel with a high rpm pinion gear. I am hoping I didn't chip a gear or two off the flywheel. How exactly can one view the entire flywheel? Is there an inspection port, or just the location where the starter mounts?
The latest grinding noise seems to be diagnosed as a shim problem on this board, but this noise wasn't there when I first did the replacement. I put the new starter in with no shims, just like the old one came out. Why would I need shims now if it didn't grind when I first replaced it? Can the bendix get lazy over time and not retract?

That's usually caused by the pinion plunger/torsion rod inside the starter hanging up. Perform the swap again if still under warranty. And I need to correct an error in an earlier post, the round tool in the box is a round feeler gague. Leaving the main battery lead off of the starter and the shorud off, have an assitant turn the key. This throws the solenoid plunger and the torsion bar forward, kicking the starter pinion into it's engaged state on the flywheel. Insert the rod between the teeth of the pinion and flywheel. If it just fits, you're shimmed right. If it's tight and drags, or does not insert, add the smallest shim in the box. It will be stamped with it's gage on it. If the round feeler gague hangs loose in between the top of the pinion teeth and the gap between the flywheel - you have too much clearance, and this will usually make a grinding noise. Delete a shim or re-shim with the smallest one in the box, mixing and matching shims until the feeler gague is snug between the teeth. Sorry about my previous error.