# engine turns over slow when hot



## khinton (Jun 22, 2008)

My 68 gto starts and runs great but after a 30 minute or so run it turns over very slowly when trying to start again like stopping and turning the engine off to get gas. When It's cold it turns over normally. :confused


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## Rukee (Feb 8, 2007)

Welcome to the forums.
I`d say your starter is heat soaked, bad battery cables or you may have too much ignition timing.


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## khinton (Jun 22, 2008)

Thanks, timming was checked and is right on--new battery and cables show no corriosion. What is starter "heat soaked" and how do i fix it?


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## 05GTO (Oct 6, 2004)

khinton said:


> What is starter "heat soaked" and how do i fix it?


Heat soak is when your wires and/or starter are overheated causing excessive resistance and does not allow enough current to start the engine. Best way to fix would be to inspect all wiring and route away from exhaust manifolds. May also be a starter in the early stages of failure.


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## VettenGoat (Jun 19, 2007)

I used to have the same problem with my 68. Its fairly common particularly if you are running headers. A heat sheild between the solinoid and exhaust will help some, but my guess is you'll be replacing your starter soon. Mine got so bad I had to wet it down with cool water just to get to start, replaced it shortly thereafter and fabricated a tin shield for the solinoid. Worked fine after that.

Mike


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## MPR6679 (Jun 25, 2008)

I had the same thing happen a few years ago with my '66. At at cold crank, the starter pulled around 250 amps. On a hot start, it was around 650 amps and was very slow to crank.

The battery was quite weak, and the cable ends had quite a bit of corrosion. A new battery was installed as well as heavier gauge cables. These repairs did NOT fix it, though it did crank marginally faster when hot. The starter was removed and inspected, and found that a combination of heat and excessive resistance caused the contacts inside the solenoid to become severely pitted.

The starter was rebuilt, and it fixed the problem. I added a heat shield afterwards to try to prevent future heat-related failure.


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## Rukee (Feb 8, 2007)

^^ Good job ! Welcome to the forums.


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## ppurfield001 (Jan 21, 2008)

Rukee said:


> ^^ Good job ! Welcome to the forums.


Rukee, your car looks sweet and surely will turn heads this summer. Glad to see that you recovered from the rains. Regards, Paul.


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## 70455goat (Nov 5, 2007)

*Got the same problem on my 70*

Funny!!! I have the exact same problem on my 70. I am pretty sure I know what it is. In fact, I already have a new starter soloniod sitting on the work bench.

Had the exact same thing happen to my son's chevelle and it was the starter solonoid. Replaced it and the problem was gone. He has headers that was heating up the solonoid. One of these days, I want to put shorty headers on it.

I still wouldn't rule out some of the other ideas: timing, wore out &/or loose wiring, headers heating up the starter/solonoid.

Good luck,
Dale



khinton said:


> My 68 gto starts and runs great but after a 30 minute or so run it turns over very slowly when trying to start again like stopping and turning the engine off to get gas. When It's cold it turns over normally. :confused


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## binaryartisan (Aug 21, 2008)

I used to have the same "heat soak" issue, but replaced starter core with a bar-wound armature. Solved the problem. Costs more though, check with a rebuilder.


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## Rodman (Mar 23, 2011)

i have a 70's gto with new starter and heat shield, any ideas on how to fix this hot start problem? The battery is new but im not sure about the cables, they might need to be replaced. thanks in advance for all help.


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## freethinker (Nov 14, 2009)

Rodman said:


> i have a 70's gto with new starter and heat shield, any ideas on how to fix this hot start problem? The battery is new but im not sure about the cables, they might need to be replaced. thanks in advance for all help.


which starter do you have? it hasnt been mentioned on this thread that there were two starters for gm products back then. the bigger engines got a high torque starter. smaller engines got a low torque starter. most of the rebuilt starters floating around are the low torque variety.
the way to tell is look at the solenoid to starter brass connection under the battery cable connection. if it bolts right to the solenoid its the shorter low torque starter. if it has an extension of about 3/4 inch it is the longer hi torque starter.


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## dimitri (Feb 13, 2009)

Is it corectly shimmed? Inline tube sells a shim kit that comes with instructions, shims, and a gapping tool for $12.00. Best twelve dollars I ever spent.


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## 6tee7 (Feb 24, 2011)

I had the same problem with a chevelle, I bought a remote solinoid kit from a company called Madd Interprises, fixed the problem. Found out later it is really just a solinoid for a Ford, but it sure worked.


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