Won’t restart with hot engine
Drifting
Joined: Jun 2025
Posts: 1,672
Likes: 582
I'm no EE.
Permanent Magnet Starters draw aka require Less current than older 10MT starters do; because 10MT starters have both field coils & pole shoes and those coils Require current to create a magnetic field. PM starters have Permanent Magnets (in lieu of any field coils); thus require No current to produce a required magnetic field. Both starters Require current for their armatures; Permanent Magnets don't. Furthermore, Field Coils are negatively affected (by heat) on electrical impedance-resistance while Permanent Magnets' Fields are Not so affected.
As a result of the PMGR starters' improved design, the PMGR starter produces More work with Less current than old 10MT design. GM got it right, again.
Most GM V8's delivered over past 30 years were delivered with PMGR starters. Compared to the previous 10MT era, I speculate the present PMGR era experiences a considerably reduced percentage of starter failures.
The old 10MT was a great design, but time and design-manufacturing capabilities move forward; often to our collective benefit. And I can't recall hearing or reading about a gaggle of '95 thru 2002 pickup owners replacing their OE PMGR and retrofitting a 10MT.
Permanent Magnet Starters draw aka require Less current than older 10MT starters do; because 10MT starters have both field coils & pole shoes and those coils Require current to create a magnetic field. PM starters have Permanent Magnets (in lieu of any field coils); thus require No current to produce a required magnetic field. Both starters Require current for their armatures; Permanent Magnets don't. Furthermore, Field Coils are negatively affected (by heat) on electrical impedance-resistance while Permanent Magnets' Fields are Not so affected.
As a result of the PMGR starters' improved design, the PMGR starter produces More work with Less current than old 10MT design. GM got it right, again.
Most GM V8's delivered over past 30 years were delivered with PMGR starters. Compared to the previous 10MT era, I speculate the present PMGR era experiences a considerably reduced percentage of starter failures.
The old 10MT was a great design, but time and design-manufacturing capabilities move forward; often to our collective benefit. And I can't recall hearing or reading about a gaggle of '95 thru 2002 pickup owners replacing their OE PMGR and retrofitting a 10MT.
Melting Slicks
Joined: Oct 2012
Posts: 2,156
Likes: 273
From: Dunedin NZ.
My 1974 Corvette has a hot start issue I’ve been unable to resolve. It starts without fail when cold and I can push start it when hot. All other electrical comes on but when I turn the key after the engine warms up the starter won’t engage. I’ve pulled the starter and had it tested. No issues. I pulled the solenoid, cleaned the leads and replaced it with a new one. I pulled the starter ground and battery ground to the frame and cleaned them up. I’ve replaced the battery and I placed a heat shield around the starter. I checked wiring as best I could and tied it away from hot areas as best I could. It still doesn’t restart hot. Does anyone have suggestions on where I go next?
