I've noticed it in the last year (2013) that my 2008 Jetta with the original OEM battery would be taking a little longer to start than before, sometimes (but very rarely) not starting in the amount of time I try to have it start through my reflex of using it for 5 years.
It was all still good, even in the freezing temperatures, until today -- I haven't driven the car in about 8 days (it was stored in a garage around 32°F), drove it to a gas station today, then to uni; as I drove to uni, I've noticed that there's some kind of slightly burned smell coming out from the heat (but I kinda thought it was normal, since I've been using the windscreen vents most of the time earlier, but was using the driver/passenger vents today), then I notice that the front lights were kinda flickery as I spent a couple of seconds idling at my destination, and idling was slightly uneven.
Subsequently, the car didn't start back at this destination -- at the uni. I kinda panicked, and attempted to start it several times in a row, only then realising that I better apply the manual break to turn off DRL, and then it finally started on like 6th time (after having to wait a minute or so from the prior attempt of trying to start it right after the DRL went off), but idle was very uneven and the lights flickery, plus the engine light was on.
I drove it for a while, and idle was still very uneven and lights were blinking; I then realised that I better turn off the heat (and also radio, just in case), I drove the car like that for like 10 miles around town (to recharge the battery), trying not to idle it, still with the engine light on (but idling was now very stable since turning off the heat), then left it off for one or two hours in the freezing temp (20°F) at a Walmart.
After that, the car started just fine at the Walmart -- no issues or delay whatsoever, however, the engine light is still on, and I am kinda getting the impression of receiving somewhat of a weird burned smell from the heater (I've tried to only keep it on when driving on highway), however, upon my arrival at home, and opening the hood in the garage, there was no burnt smells from within the hood whatsoever (the smell from the heater was weak, but I haven't noticed anything like that before; although, to be fair, I haven't drive the car in 8 days). I've inspected the top of the battery, and it's also just fine.
- Any ideas what's going on?
- Is starting the car with the low battery damaged the engine?
- Is there some problem with the heater?
- Is the check-engine light being on due to a more-than-usual dying state of the battery?
- Do I have to change the battery, or is it just the extra cold weather and several days of not-driving that gave it a hard time?
I'd like to stress again that the very last time I've used the starter (at Walmart), after recharging the battery by driving 10 miles without heat, there was absolutely no signs of the battery being dead (alas, I did have the heat, DRL and radio off during this starting), so, I'd rather not replace it now if it can still serve me for a while.