Starter or flywheel

no-mas

LifeTime Supporter
Jun 16, 2008
405
FL
So my son tries to start his '03 Subaru yesterday, and it makes a grinding noise when he turns the key... not good. Second try, starts right up.

When he got home, I tried it... same thing. Grinds first time, engaged and started the second.

This morning - started, no grinding.

Anyone mechanically inclined (cough - Richard320 - cough) know how I can differentiate between a starter problem vs ground teeth on a flywheel? What would cause the flywheel teeth to wear if that is the problem?

I plan on taking it to the mechanic, but want to have an idea of what to be looking for... Thanks for any advice!
 

dmanb2b

TFP Expert
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Apr 4, 2009
3,734
NY
To me it sounds like the starter is not fully enaging with the fly wheel and is on it's way out...but that my shade tree mechanic guess
 

lbridges

LifeTime Supporter
Nov 12, 2009
323
Indialantic, FL
There are several possible things that I have experienced.

Starter problem - not likely to be teeth on starter as there aren't that many and they would hit on every attempt to start. However, the starter solenoid may not be fully pushing the starter gear out to engage with the flywheel, In general the process is solenoid pushes gear out to engage with flywheel/ring-gear (latter for automatic trans cars), then starter motor spins. If the solenoid is "sluggish" the starter could be turning before the gears are engaged, hence grinding sound (highest probability). Hard to troubleshoot without removal and test bench (most places just do a parts swap - and keep in mind no return on electrical parts).

Flywheel/Ring-gear problem - missing or damage teeth - not as likely as they tend to be harder, but all things are possible, especially if this car had lots of attempts to start it after it was already running (if you know what i mean). Much more expensive fix as transmission/trans-axle will have to come out. Could be determined by getting car in the air and slowly turning the engine over (manually) while looking through an inspection area (usually at bottom of engine just where it joins transmission).

My last Subaru was a 1992 SVX (weird windows car). Starter replacement required disconnect battery ground cable, remove positive cable (thick one with a nut to hold it on) from starter, remove solenoid wire from starter (thin one with a spade connection), and remove two bolts holding starter to engine. Reverse to install new/rebuilt unit.
 

Bama Rambler

Mod Squad
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Jun 22, 2009
23,052
SouthWest Alabama
Hopefully Richard will be along soon, but to me it sounds like it could be either or maybe a little of both. The first thing I'd do is make sure all the electrical connections are clean and tight. That'll keep the pinion from engaging the flywheel properly.
 

no-mas

LifeTime Supporter
Jun 16, 2008
405
FL
Thanks guys. I know that a starter will be a simpler/less costly fix than a flywheel, and am hoping for the former. My son tells me that he has tried to start the car when he didn't realize it was running, but only once, many months ago. I'll check/tighten all the electrical connection this evening and see what happens. I'm not likely to try to swap a starter on my own, but certainly do appreciate y'alls input.
 

Richard320

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Jan 6, 2010
20,903
San Dimas, CA (LA County)
The only way to know for sure is to remove the starter. Make a crayon mark on the ring gear. Put a breaker bar on the crankshaft pulley and have one person slowly turn the engine over while the other looks through the starter hole with a flashlight looking for broken teeth. When you get to the crayon mark, you know you've gone 360 degrees.

Typically what you'll find are some mashed looking teeth, where the starter drive has been grinding on it. Occassionally you'll find a missing tooth, or a whole patch of teeth in a row that have been ground off to about half thickness.

The starter drive gear has some bevelled edges. They work as a wedge. When the gear engages, it should slightly bump the ring gear to allow the teeth to line up and fully engage. When the gear is all the way in, the contacts in the solenoid close and let the starter motor spin. Something's not working right with the sequence on this car. Probably weak pull-in windings.

Assuming no flywheel are teeth totally destroyed, you need a new starter solenoid. Sometimes they're not serviceable separately; I'm not sure of Subaru. And often a rebuilt starter with a solenoid is cheaper than a new solenoid. Spend a little extra and avoid the cheap places like Autozone, Kragens, Chief. Their rebuilt parts come with a lifetime warranty, which is handy, because you'll be changing them every few weeks for the rest of your life..
 

no-mas

LifeTime Supporter
Jun 16, 2008
405
FL
Richard320 said:
....Their rebuilt parts come with a lifetime warranty, which is handy, because you'll be changing them every few weeks for the rest of your life..
Ha! - Thanks for the advice