330,000 km on car. I drove 45 minutes when battery light came on on and car engine stalled when making a left turn (fuel light had just come on too but not empty) and restarted on own, drove 10 minutes and it stalled again, so I pulled over and restarted. Drove 45 minutes home. No issues since. Shop says 10 year old battery and alternator are testing fine, though they suggest replacing alternator as it may be going. Could there be other electrical issue since the issue is more intermittent? Car would not stall immediately if alternator failing I would think - should run on battery for a bit and not restart. Drive maybe 400km per month and it sits for 10 days at a time. Thx
I’d replace that 10 year old battery, just out of principle
Then check the charging system . . . you’ll probably need the alternator in the end, also
Make sure your alternator drive belt and tension are good
The alternator’s brushes are probably worn down to nothing, which means you probably need an alternator . . . because you probably won’t want to rebuild it yourself, right?
That 10 year old battery should be replaced.
I worked eight years in retail auto parts. I was the Single Point of Contact (SPOC) - battery ‘expert’ - in my store. Average life of a battery in the USA is 58 months (~5 yrs). A ten year old battery in good condition is rare but not unknown. Oldest I saw was 12 yrs pulled from a farm tractor.
If all your battery connections including grounds to body and frame are in good condition then your battery could be suspect.
As another possibility, it could be your fuel pump and/or filters. The fuel pump is on the left side of the fuel tank. Going around the left hand turn would slosh the fuel to the right hand side. With a lower fuel level and a partially clogged fuel pump inlet filter or weak pump, your car could have lost pressure starving the engine for fuel making it stumble. This could also cause the alternator to slow enough for the circuit to turn on the battery light. (The ‘battery’ light really tells you nothing about the battery but indicates that you have insufficient/no alternator output.)
Replacing the fuel pump and its filter in my '94 Corolla wagon is through an access port under the rear seat and doesn’t require dropping the fuel tank. The pump by itself can be replaced without replacing the entire assembly. Always replace the suction inlet filter when you replace the pump. Normally, the filter is only replaced when the pump is replaced. Although I did have to replace the filter in a '95 Corolla wagon that I bought that had sat for a year.
There is also a fuel filter on the left side firewall in the engine compartment. It is cheaper than the fuel pump, easier to get to and should be replaced periodically anyway.
Also keep in mind that the fuel pump sits in the fuel. If the car is consistently run with very low fuel levels, there is little or no fuel in contact with the fuel pump body to help cool it. Over the long term in severe climates or severe use this combination of factors can decrease pump life.