CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Starter grinding BAD '85 K5 Blazer

I’m hoping someone here can tell me what my issue is. I have a 1985 Chevy K5 Blazer, the starter was grinding horribly so I replaced it with a brand new last night and it started perfect. I wake up amd start working on it today and its grinding just as bad as before horrible loud grinding and the whole blazer shakes, I didnt install any of the shims but the feeler gauge was pretty close to perfectly spaced, the bolts are nice and tight so.i know it’s not moving. What’s the deal? The blazer has been sitting for 18 years so could it be a problem with the flywheel instead? Theres not missing teeth and it isn’t locked up as I can spin it by hand. Someone help!

You need to use the shim kit. It’s cheap and easy. If this keeps up you WILL be replacing the starter motor and possibly the flex plate also. The latter means the transmission has to come out.

1 Like

What can you spin by hand?

Maybe the flex plate has cracked or rusted through near the crank flange.

The flywheel, I can spin it by hand towards the driver’s side.

What would be sign’s to look for in that case?

Shim it even though it gauged properly?

I would remove the splash shield and check to see if the flex plate moves front to back when the starter is cranked.

1 Like

Let’s clear up something, please

I’ve read this entire discussion, and the other one, as well . . . the one that’s now locked

And I’ve read the term flexplate and flywheel

It’s either one or the other

If you’ve got an automatic transmission, you’ve got a stamped steel flexplate

If you’ve got a stick shift, you’ve cat a cast iron flexplate

stamped steel flexplates are known to crack from time . . . usually where it attaches to the crankshaft . . . so then you can have a situation where you can manually bar over the engine, from the front, yet the actual ring gear isn’t moving. And when you hit the starter, the ring gear turns, but the flexplate, and of course the engine itself, does NOT turn. Thus, no start

2 Likes

Db sorry about that I think it’s just one of those things that has become interchangeable with most people over the years but I do indeed have an automatic th350 trans thus I have a flexplate and the engine will start but it grinds more than it starts, let’s say roughly 9 out of 10 starts it will grind.

Thanks for the information

I now agree with the others . . . you need to use the shim(s)

Please make it clear, can you actually turn the flywheel/flexplate with your bare hands? If so how freely does it turn?

From the hip I am guessing that you installed the new starter with too little clearance or unevenly and then started the engine resulting in shearing the flex plate around the crankshaft hub.

You don’t even have to fully remove the starter to add a shim. Remove one bolt, loosen the other, and try one of the thinner shims as a first step. If grinding still persists then go with a thicker shim.

Back about 1980 a friend of mine bought a new Camaro Z-28. In the first year he went through 3 starters and 2 flexplates; all under warranty. Apparently the Chevy dealer here of all people was unaware of the shim issue…
The last flexplate failure is what caused him to get rid of the car and be done with it.

So I installed shims, I tested the 1/8 clearance that is commonly used as the guide, same grinding. I removed two of the shims (I needed 4 to get the 1/8 clearance) and it started perfect without a single sound. I started the blazer about 10 times going through a fuel pump issue, I go to start it for roughly the 10th or 11th time and grinding again just as bad as before. Any ideas?

Yes, the flexplate turns using my bare hands and it takes a little effort but really not much at all. If you grasp the flexplate with both hands and turn the flexplate and torque converter both rotate towards the drivers side of the blazer at the same time.

There would appear to be a serious malfunction somewhere if you can turn the flexplate if it is intact and attached to the crankshaft. The only similar situation that I have ever come across that wasn’t a sheared flex plate was a crankshaft broken in the rear main boss.

I checked the flexplate and torque converter and there is no signs of any missing, broken or chipped teeth and no signs of any bending, cracking or breaking anywhere. How do I pull the starter gear out so i can double check the fitment that way? I tried putting something in there to hook in and pull it out but can’t get a good grip

Disconnect the positive cable from the starter, when you activate the solenoid the starter drive will extend but it won’t rotate.

I don’t get the multiple shims part of this. I’ve shimmed many of them and never had to use more than one shim. Start with a thin shim and if the noise persists remove that shim and go with a thicker one. Wash, rinse, repeat until grinding is gone. Just the way I’ve always done it and I’ve never concerned myself about the 1/8 clearance. And no comebacks either. Comeback being mechanic speak for screwup…

Just some food for thought since this is a 35 year old vehicle. Any chance the crank thrust main bearing could be worn out and allowing the crank to walk back and forth? Maybe pry the harmonic balancer forward and then force it backwards. There should be very little noticeable movement.