Which Sterter Solenoid?, Looking to remedy the infamous hot-start issue Options

[JDW914]

Hi all! I recently took my first long road trip in my 914 (700 mi round trip out to Peoria, IL to finally pick up a replacement windshield) and while the car performed beautifully, I had my first encounter with what I've learned is the "infamous hot-start issue." Happily I was caravanning and, when unable to find a clear reason as to the car's failing to start after a pit stop for lunch, we tried jumping it, assuming the battery had gone bad, which resulted in enough current to pop the solenoid and start it up. This was necessary a few times during the trip. While it has never caused me trouble before (I've been driving the car pretty regularly for 2 years since its restoration has been "finished") I'd prefer to remove the issue so that it doesn't come back to bite me, especially now that the car has proven itself as such a good road-tripper.

Now in my research since encountering the issue, I've found much documentation of the issue and its solutions, in particular a Ford starter solenoid or a Bosch hot start relay kit. I'd like to go about it with the replacement starter solenoid as this seems a simple and straight-forward enough change-out, however, I've not been able to determine what solenoid it is in particular that will fit into an old VW starter motor. Is there a particular part number or set of models/years that use it, or does Ford have enough standardisation that any old solenoid will work?

Thanks for any enlightenment you can provide!

[JDW914]

To be clear, my car's problem is that at high running temperature (several hours of ~3000rpm in hot weather) the solenoid on the starter motor does not deploy when the key is pressed to the start position; I get a quiet, rapid ticking from the starter and nothing else. This is a brand new Bosch starter and a direct replacement for the original.

I *had* been under the impression that the Ford solenoid fix was a replacement of the solenoid on the starter, but apparently that is not the case? What does the relay circuit do that improves current flow to the starter

[Mark Henry]

To be clear, my car's problem is that at high running temperature (several hours of ~3000rpm in hot weather) the solenoid on the starter motor does not deploy when the key is pressed to the start position; I get a quiet, rapid ticking from the starter and nothing else. This is a brand new Bosch starter and a direct replacement for the original.

I *had* been under the impression that the Ford solenoid fix was a replacement of the solenoid on the starter, but apparently that is not the case? What does the relay circuit do that improves current flow to the starter

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