No re-start when hot.

sjmst said:
Starter engaged but slow, labored cranking. Not ever the case when car is cold.
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Following this latest discussion of starter VS solenoid, I happened to come across your earlier comment (quote above) again. That statement leads me to think more 'starter motor' than 'solenoid switch'. Old worn starters build up greater resistance which reduces cranking speed and torque, eventually to the point they stop turning completely. Heat increases resistance even more, so it will compound a worn starter's problems making it intermittent prior to finally dying for good. The "tap on it to get it turning again" is usually a sticking solenoid. Without the solenoid moving freely the starter won't turn at all or just "click". The tapping frees it up. In your case it is turning but slowly (especially when hot), so more likely its the starter motor than the solenoid switch. But as Rod says they usually come together as a unit, so both will get replaced at the same time. Do some tests as mentioned earlier to confirm it is indeed the starter/solenoid unit first, and not some other issue.
 
I had a Ford Escort which would turn over very slowly when hot. Turned out that I was advised that something was tight in the engine when hot although I never found out what. I changed all the usual suspects with no joy. It was a pain in the neck at a time that I could not really afford it.
 
I had a hot restart issue with my 84 X. Would start fine when cold but after driving around and stopping would take a lot of cranking to get restarted. In my case it was a bad fuel pressure regulator.
 
I may have found my problem. The negative battery wire clamp was worn/loose. Not sure why driving as opposed to idling affected it but I replaced it and so far so good.
 
Might be worthwhile buying a new cable - the terminal clamp should be crimped to the cable- the American-style clamp over wire to terminal posts are a really bad design & prone to failure. Very easy the replace the negative cable as a whole.
 
Also I've found a lot of cables with deterioration somewhere within the cable itself, not just at the terminal. So if the ends look bad, the entire cable may be as well.
 
Then most likely it gets back to what we were discussing earlier. The motor is wearing out and when it gets hot resistance goes up, slowing it down.
I have a old air compressor that I keep as a back up. It still works but due to its age the tank has corrosion inside, the various air connections on it leak no matter how often I reseal them, and the electric motor builds up a lot of heat. The longer it runs the hotter the motor gets until it shuts down (overload protection). In the past I replaced the bearings inside the motor (they were cheap and easy to do), but that did not help. I even tried cleaning all of the motor's internal components and connections, but no improvement. Its the electrical windings inside that have aged and increased in resistance.
Similar thing happens when starter motors get old.
 
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