My water pump failed on christmas day, 2008. luckily, there was a lot of traffic so i was only going about 20mph and my pistons were not damaged. after my water pump was replaced, i noticed a "diesel" sounding noise when i accelerated when i arrived home. my water pump was installed at 7000 ft in elevation, and i live down the mountain. i can only hear the sound where i live, and when i drive up the mountain, the noise disappears. this is what made me believe it had something to do with air intake. it makes this noise very loudly when i accelerate onto freeways and up hills, and it seems more sluggish than it did before. it's even worse when my a/c is on. in fact, i was in a drive thru earlier today and noticed that when it was idling with the a/c on, i could hear the noise. when i shut the a/c off, the noise when away when i was idling. when i'm accelerating however, it's always there. my dad (who's also my mechanic) thinks that it doesn't affect anything. i've never overheated and my fluids are fine. i maintain my vehicle every 3000 miles, and this is the only thing that is really wrong with it. i can't put my finger on it. i also don't want it to get worse because i didn't take care of it. i cant figure out what i need to take care of! can anyone help?

 

I'm willing to bet you're hearing spark knock/detonation due to the timing belt being off a tooth (or more) and thus your valves are not opening/shutting when they're supposed to.

Who replaced the water pump?

Are you familiar with how to check your timing? Not just ignition timing with a timing light, but physically checking to see if your timing belt is installed in time?

 

BTW:

If my theory is correct it explains the noise, the loss of power, and why it's worse when the a/c is on as well.

It can absolutely destroy the engine if the detonation is strong enough - it can actually put little craters in the piston tops and even crack a piston ring landing. the noise you're hearing is little explosions due to the mistimed valve opening/closings.

If you lived in a really hot climate you'd be hearing it much worse too. I'm not sure how elevation affects it, but that can't be good either.

 

^ dude knows

 

my dad works with a guy who used to be a mechanic for honda. he is the one that replaced my water pump. i called my dad and told him what you suggested, and he assured me that the timing belt is on there perfectly. steve (the guy who used to work for honda) DID say my valves need to be adjusted on my next service. could this help any? since no one can really diagnose it, the only suggestion i've been offered is "it's an old car, it's gonna make noises it didn't before." i have a 98 civic lx with 131,000 miles on it, which is way below what it's supposed to. i'm thinking of taking it to a honda specialist (i have one near my house) and see if they can test drive it for me. also, wouldn't the check engine light come on and throw up a code if the timing belt was off or if there was something wrong with the engine? the only time my check engine light has come on is when my water pump first failed.

 

well if the car was running good before is something he did wrong. i agree timing belt off by a tooth.

 

well, today when i was taking it up to my dad's to see if he could look at it for probably the last time, my car overheated BEFORE the bottom of the hill. It was in the 90's and there was traffic. i was trying to not run the a/c the whole time, so i didn't waste gas. i noticed that my temp. gauge was a little higher than normal, so i shut it off. then it higher. i pulled over and sat for a few minutes. because i was impatient, i turned the car back on about 10 min. later and turn the heater on. it immediately cooled back down. i headed back home and told my dad what happened. i didn't want to risk getting half way up there with no phone signal and a dead car. i decided to call the honda specialist i mentioned in my previous post. i asked him how much it would cost to listen for a noise i'd been hearing since my water pump was replaced. he said it wouldn't cost anything and to bring it in. i took it in, and his first hunch was the a/c bearing (?). he explained it needs to be replaced usually every ten years, and mine was older than that (it's a 98 civic). he used the stethiscope and it sounded just like the noise i was hearing when it was in gear! next, he thought it could be the brake wear indicator. he said my brakes were the cheapest around and that the "metal-to-metal" sound i was hearing could be the indicator rubbing against the pad (i think). he said the indicator was close, but was not touching. lastly, he asked me if i had noticed the sound after my timing belt was replaced. i asked if you have to change the belt and the water pump at the same time and he said yes. i told him i'd been hearing it since the day i got my car back after the repair. he said he could time it, but he wouldn't be able to tell if the belt was off a tooth or not without taking the belt off. he timed it, drove it around and came back and said "it actually goes "vrooooom" now! test it out and let me know if you still hear the noise." sure enough, i drove it around and immediately i could tell it was back to normal. i was so relieved! thanks to you guys i was finally able to fix my problem...and for free, no less! with it being timed incorrectly, that explains the sluggishness, the crappy gas mileage, the overheating, the noise and hiccups from a dead stop. THANKS GUYS!!!!!

 

Sorry to reply so late, and i have a feeling the OP might not be back to read this any time soon, but I thought it important to say this:

I'm not seeing a correlation between timing being off a tooth and overheating. In theory the poor timing could have been causing enough spark knocking, lean burning, and detonation to possibly cause overhating, but it's just not very likely IMO.

My hunch about timing was correct in that it took care of the diesel noise, but I would not have suggested timing being off as a cause for overheating...that's just odd.

I'd suspect something more along the lines of a thermostat sticking shut at random, vausing overheating.

 

Another possibility is that the cooling system was not properly bled after draining and refilling the cooling system for the water pump replacement.