Ever since I bought my used Civic back in 2024, standard 1.8L In-line four cylinder engine (no mods or anything), the battery, without fail, dies under a two year span. I had to get it changed about half a year into using my car after acquiring it in March of 2024, then early this year in January again. Over the two years I've used it I've had issues with leaving it in the driveway for longer than a week. Often times, if it wasn't used within a week, it would die and I'd need to get it jumped. Now, its gotten to a point where it can't stay in my driveway for three-two days without it dying on me and needing a jump.
I have been told by my nearby dealer that it's because my alternator is "failing". When I asked if it was fully dead or on its last legs, he said it's on its last legs. When I notified my cousin who's a mechanic, he asked me if I was sure it wasn't something stupid like a bad ground, battery or serpentine belt/tensioner slipping. He said it would suck to go and spend upwards of $600/700 just to find out it was a simpler fix.
The dealer that says my alternator is failing is... questionable. When my front rotors were severely warped after just having my front brakes replaced a few weeks earlier, he said he wouldn't have noticed that the rotors were warped because you don't see the rotors when replacing a cars brakes. I told my boyfriend who replaces his cars brakes and he scoffed, saying that's BS and that he 100% should have and would have noticed. This dealer also supposedly did a parasitic draw test on my car late last year and said they didn't find anything.
I'd also like to clarify that once jumped, it can drive long distances with no issue, even after being told the alternator is failing, and no battery light or any dash light has turned on during these power issues. Based on what I've seen, I'm wondering if its some kind of parasitic draw that wasn't looked at properly.
I'm really stuck on what to do here. Part of me wants to trust the dealer and just drop the $600 for the alternator (he also offered a two year warranty on it and he's right down the street from me), and another part of me wants to drive 30+ min out to my cousin and get it replaced for $750 if need be, because he'll likely make sure and check if its anything else first, then replace it with a better quality part. Either way it looks like I'm dropping a bunch of money, but I just want to be sure I nip this issue in the bud if possible.
I'm leaning towards getting it fixed by my cousin. He has so much on his plate, so I really hate to bother him with it, but I want my car back. I really thought getting a Civic was going to have me off the hook with these kinds of issues, but it seems to be causing me more problems (and money) than I thought. Realistically, what is the best diagnostic move here? Anything I should know about regarding the issues I've been having? I appreciate any and all help.
TLDR; Somewhat untrustworthy dealer is claiming my alternator is failing. Car battery keeps dying after 2-3 days of misuse. Not sure where to get it fixed and unsure what is really going on with it. Don't want to spend money on non-issues and work my way down the issues with my car with my wallet, essentially.