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Ask Mechanic Martyn Your Own Question
Mechanic Martyn
Mechanic Martyn, Mechanic
Category: Car
Satisfied Customers: 1002
Experience:  Advanced trade certificate in Automotive engineering
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I put a new for about 15 to 20 min the car shuts off

Customer Question

I have a 1976 spider. I put a new alternator in this week and seems to work well, but after driving the car for about 15 to 20 min the car shuts off. When you turn the key there is no sound. I can then jump the car and it will run well again for about 20min. The battery is old. Do you think a new battery is the answer or could there be some electrical issue?

Charlie in Memphis
Submitted: 5 years ago.
Category: Car
Expert:  Mechanic Martyn replied 5 years ago.

Hello and welcome to Just Answer

The job of the battery is to supply the energy needed to start the car and a smoothing action for the output of the alternator.

It sounds like yours is doing neither.

Replace it with a quality brand.


Mechanic Martyn


Customer: replied 5 years ago.

I thought I did send that I accepted your answer but I would like to add some information. I am going to replace the battery, but the car will start now without being jumped. When it cuts off it is like some thing was disconnected. So, that made me think it was a connection problem, not just a battery problem. Give me your thoughts, and I will make sure I click the accept answer.




Expert:  Mechanic Martyn replied 5 years ago.
Hi Charlie. My thinking goes with an overheating coil due to the alternator voltage not being smoothed by a faulty battery. However I would reccomend due to its age that you check every connection carefully, especially the earths.
Regards Mechanic Martyn