Battery, alternator or something else?

Here is what I’ve been currently dealing with with my 2004 Honda CR-V with 255k.

Temp gauge reaches its peak if I’m idling for too long (usually 3-5 mins), cools down once I begin driving again.

After driving for a good amount of time (15+ mins) and turning my car off, it struggles to turn on again shortly after (even if temp gauge never got to a higher temp than normal). It will crank but not turn over. I often have to wait 20-30 mins before it will start again.

Yesterday while in stop and go traffic, my car battery somewhat died. Radio turned off, lights turned off, dash had tons of messages lit up (battery light was flickering) but my engine was still running and I was able to still drive safely to a place to stop. Before I had a chance to even turn the car off, everything came back on, so I continued home with no problems (making sure to be at idle for the least amount of time as possible).

During my last oil change, I was notified that they could not get a read on my battery, so there is a chance it’s a battery issue. But is there a chance it’s the alternator instead or as well? I also thought one of my fans may not be working and thought that was the cause of my engine overheating while in idle.

Any thoughts or suggestions would be greatly appreciated!

kind of sounds like you need to replace your alternator. If you want to keep the car that is. It also sounds like there is something wrong with your radiator or water pump.

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You need a voltmeter and a little diagonistic time. Car off, at rest the battery voltage atthebattery terminals should read above 12.3 volts. Engine running, the voltage should read 13.5 volts or above but less than about 15.5 volts. Lower than that may be a bad alternator. Have the battery tested, at least, for free, at an auto parts store. If it is bad, buy a new one and see if it fixes what I think are mutiple problems.

You didn’t say if you check engine light, or battery light on the dash are on… so are they? If the check engine light is on, what are the codes?

If you don’t have tools like this or don’t feel diagnosis is something you can do, don’t just throw parts at the car hoping to fix it. That rarely works.


If you don’t find the problem(s) following @Mustangman advise the next step is to check your battery cables and cleaning them is a must. If you still have overheating, you can check the fan. It should turn on at idle when the designated temperature is reached. There are multiple ways to check it so a web search for your specific car should guide you through the process.

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Check engine light is on, but has been since I got it due to needing an O2 sensor replaced. I’m sure there are more codes being thrown at this point, but I haven’t had the chance to check. I’ll go and get the battery tested but when I went for an oil change, they said they couldn’t get a read on it, so I’m not sure if the auto parts store will be able to either. I guess we will see!

Are you using a ‘quickly lube’ type place for oil changes? A legitimate shop would have told you more than they “couldn’t get a read” on your battery.
Seems you have several problems, postponing repairs does not help.
As far as the when warm, crank but no start, crank shaft position sensor.
Getting hot when at idle, could be fans, could be partially clogged radiator.
Time to bite the bullet, take it to a mechanic, pay to get it diagnosed.


Overheating your engine repeatedly is likely to damage it. Today’s engines are easily damaged by that.


If you are using a quickly lube that is a big NO NO and may cause more problems.

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The battery and charging system test seems the number 1 priority. Making sure the engine compartment fan(s) are working is probably next. If those don’t spin when they should you’ll get overheating in stop and go traffic or idling, but ok when driving at 35 mph+.

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