Starter, Alternator, Both?

My 1995 Subaru has decided that it’s just too cold this winter - or something like that. Even though the battery is only 1 year old, it is dead. OK, I thought, I’ll bring it back and get a replacement. But when I try to jump start it, it just barely cranks. The lights dim, the jumper cables get hot, and the car still just barely cranks - and does not catch. So now I’m thinking I need a starter. But then why is the battery dead? That would suggest the alternator, but a bad alternator wouldn’t keep it from starting, would it?



So before I have it towed and spend more than the car’s book value to replace the alternator, starter and battery, any ideas as to what is really wrong?

Why do you think the battery was DEAD? Was its voltage down to 4 volts, or less? Maybe it was just discharged to less than 10 volts? Yes, the difference between DEAD and partially discharged makes a LOT of difference. A battery which just barely makes the engine groan can still put out 100 amps. That’s why a jumper battery is also called a BOOSTER BATTERY. It BOOSTS the charge of the other battery. Make sure that all corrosion is scraped from inside the loops of the battery cables and battery posts are shiny.
What size are the jumper cables? If the gauge is too small, they may have too little capacity to carry a starter’s need.
It’s possible for a battery cable to be touching the body of the starter solenoid and losing charge that way. The solenoid body and the starter body can have electrical shorts. Check the cable connection at the starter.

I wouldn’t blame the battery, starter or alternator until the battery was fully charged and you see what happens. You may have a bad connection, or have something that is constantly draining power from the battery. Is the top of the battery clean? Once it starts, does it run fine? If it runs fine then your alternator is probably ok. And if you have a very discharged battery, it may take 10 minutes or more sitting there letting the jumper car charging the battery of your Subaru, epecially if you have cheap small guage cables.

The battery did not even have sufficient power (prior to jumping) to light the dome light in the car, much less turn provide enough current for the starter to turn at all. The battery cable connections are good and the jumper cables have been used successfully before, so I don’t think the problem lies there. After unsuccessfully trying to jump start the car, the battery has some current - the dome light now shines dimly.

So the battery was at least very badly discharged, and the starter would seem to have a problem, since I couldn’t jump start it. It’s particularly odd, since the last time I drove the car (a couple of weeks ago) everything was fine. An electrical short might explain both situations - the dead battery and the inability to jump start - but without a diagram I think I’ll have a hard time tracing the cables.

The jumper cables getting hot is not a good sign. Your cheapest approach is to buy a new battery, or a battery charger, the kind you plug in. Sounds like the battery is the problem in spite of the newness.

For ShadeTreeMech77, “Once it starts, does it run fine?” No, the whole point is it doesn’t start.

The car is almost 15 years old so it must have a good amount of miles on it. Make sure the engine is not starting to seize up. With a car this old the engine should be so loose that you could probably crank it by hand. You might be lucky and it is the starter - if the starter is as old as the car.
I restore old muscle cars and when I initially start a newly rebuilt engine the starter works so hard it starts to overheat the starting circuit. So, as you can see, if there is a part seizing in tat engine it wil overwork the starter. A real quick check to do is to take the radiator cap off and see if there is any coolant in the radiator. You might have what is called “Hydro-static lock.”

Norm!! You’re all over the map here, Budday! The car either is seizing up or is so loose you can crank it by hand (crank it, honey!)?

You restore engines, but not the starters?

By all means, the OP should check for radiator fluid, but wouldn’t “a real quick check” involve the gas tank?

Here is an excellent article for diagnosing a battery that runs down: http://www.aa1car.com/library/battery_runs_down.htm
There is no way around using an electrical multimeter in troubleshooting electrical systems.
Go to www.autozone.com to get the wiring diagrams for your car. You need those, also.
As stated, recharge the battery before trying to start the car. Then, you can chase any electrical drain.

Thanks for all of the advice. I decided to try 2 sets of jumper cables on the theory that if the cables were getting hot, they must be providing too much resistance. It worked, and the car started and ran fine for a half hour drive. At the end of the drive, I shut the engine off and was able to restart it - but it didn’t turn over too convincingly, so either the battery needs more charging or needs to be replaced.

I’m guessing that since the car ran fine and the battery charged somewhat that the battery itself is the problem, so I’m going to bring it back since it’s only a year old and still under warranty. My only remaining concern is whether there’s some kind of short that caused the battery to discharge. How would I test for that?

Steve,

Have a full load test done on your charging system (in car), so as to rule out possible bad cable/wiring/connections.

Poor wiring/connections in the ignition system, between the alternator and battery to the starter or a bad ground connection will cause charging problems.

Check the ground between the engine and chassis too. They ALL have to be clean and WRENCH tight.

In case you also have a parasitic discharge, ensure all power drawing components are off when the ignition key is turned off.

For example: when the glove box is closed is the light off?, same goes for the trunk light and underhood light and interior lights.