Hello, I'm new here, and I hate introductions. Call me Mag, Magnum, or Connor if you like. I live in Worcester County, Massachusetts.
Anyways, I've had my Civic (a 2007 model) since April, and I've done three oil changes (I changed the air filter last June and I'm really surprised it hasn't needed changing since). The First one was in July, and I had no problem then. The next one was in October, and initially I didn't have an issue. But, after a month, I had to drive out to Ohio, and by the time I got to New York, the engine was making noise, a sort of constant rumble that was noticeably louder than normal. It didn't sound like exhaust noise to be sure. This was 1000 miles after the oil change in October. After I got back from Ohio, the engine was still making the noise, and continued to do so for another 2000 miles (a total of 4600 miles after the oil change). After that the noise pretty much disappeared. I did an oil change about 10 days ago, and I've been to Albany twice since then. The first trip was 300 miles round, and no noise. I put on another 200 miles in the week between, and then this past Sunday, on the way to New York, I notice the noise is back but not quite as loud. I put on another 300 miles, a total of 800 miles since the oil change. While the noise is annoying, it doesn't sound destructive, but I would like to know if I should be worried. Also, I use only Shell 5W-20 Full Synthetic, Bosch oil filters, and I've added Advanced Auto Parts oil additive to both the October and this past oil changes. I believe it may be that additive, but I hope it isn't since I've picked up a couple MPGs since I've been adding it and it makes the morning start easier. Should I be worried about this noise or should I ignore it? And if it is fact that additive causing the problem, does anyone have any recommendations for a good additive?

 

I could only make guesses at what the noise might be. Diagnosing over the internet is impossible. As far as the additives go, save your money and spend it on something meaningful. You're using a quality synthetic oil so nothing is needed, there. The oil already has additives in it from the manufacturer. If you use a good quality brand gasoline, additives aren't needed there, either. I'd get the car into a good, reputable shop when it's making that noise and find out what it is. Something is definitely going on and it could be something minor, or it could cost you an engine. AND, it may have nothing to do with your oil changes. Good luck.
Duane