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Our 2003 Civic with just under 120k miles on it is making a ticking noise, especially under acceleration. It gets much quieter once the car is warmed up, but does not completely go away. I've adjusted the valves and it's made no difference. In the video the sound is relatively quiet, when I put the phone down and rev the engine you can hear it much clearer. Anybody have any ideas as to what I'm dealing with here?

Thanks in advance!

https://photos.app.goo.gl/zCoJ84FbMjZKSNTJ3

 
Rep Power: 512

My first instinct was rod knock, but it's not as definitive of a sound as mine was when it was knocking. Check for exhaust leaks? May be a bit of a stretch, but I've heard exhaust leaks that sound similar. Here's my rod knock for comparison.


future reference, you can "blip the throttle" from the engine bay. Just turn the rotor for the throttle butterfly valve by hand. You can see my dad doing it in my video

 
Rep Power: 518

Exhaust manifold cracked or otherwise leaking


I can't discern much in the video though

 
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Thank you for the quick reply! I agree, the sound with yours is much more pronounced. I've kinda suspected a possible exhaust leak, but have been unable to locate one. And yeah, it would have been easier to manipulate the throttle from the engine bay! To frustrated trying to figure out the issue to think!!

I should mention the car runs fantastic outside of being noisy! Not sure how much that matters, but the idle is smooth, acceleration is also smooth, no hitches, just that damned noise!

 
Rep Power: 512

When I had rod knock, engine seemingly ran fine, just some extra disconcerting noise. If you're due for an oil change, metal shavings will be the tell-tale that its your main bearings at fault.

Your noise did sound a lot more airy which made me think exhaust. Jack up the car and start the engine. Soapy water test on exhaust flanges will work for the first like... minute or so.

Any way you can narrow down the location of the sound? Mine, I was able to pinpoint to lower engine. Doing so over the internet is a bit harder.

 
Rep Power: 512

The more I listen to it, the more convinced I am that it's exhaust. Pull the heat shield for the mani/cat assembly. Those integrated cat/manifolds are prone to cracking. I've seen it in person/on these forums for your engine (d17a1 -- 01-05 lx/dx) as well as in person for a 99 dx. That could be another source for exhaust leakage

 
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I've been watching some videos on Youtube and was leaning in that direction myself!

Again, thank you all for taking the time to respond, I greatly appreciate it!

 
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I've got a crack in the exhaust manifold... as predicted!

Next question, has anybody used one of the aftermarket manifolds/cats from Amazon/Ebay and had luck with them? The part from O'Reillys is over $500, I can get a non-Honda part for around $150. I know, if it sounds too good to be true....

 
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the cat in the cheap one may go bad alot quicker than a honda one, could try calling exhaust shops and see how much it would be to weld it

 
Rep Power: 512

Damn it.. I had a response typed out and I got caught up telling the story of my old car on another forum and didn't hit the "post reply" button. That window got closed somewhere along the way

Anyways, holy crap, that's more than an exhaust leak, that runner (seemingly) separated from the flange.

The reason your manifold is expensive is because of the integrated cat. Cheaper cats may or may not work (or may even be a test pipe shrouded in a heat shield to give the appearance of a cat). It might work for like a month, then throw the dreaded P0420. Happened to me with a 49-state legal cat, albeit a high flow cat, but 49-state legal, nonetheless. I also just learned recently that that company no longer exists. lol.

Magnaflow makes 2 cats for the D17A1 that comply with federal regulations. One is listed as direct fit ( ) that sells for about $365 on Amazon. The other is "oem grade" ( ) and sells for $525 on Amazon. Neither of which will be "legal" if you reside in CA. I don't know what the difference is.

They also have a CARB-compliant one that's $370 on Amazon ( ), and that's 50-state legal. Why it's cheaper than the non-CARB OEM grade one, I have no idea.

All three of those should be direct bolt-on ones, since they are designed for the D17A1, after all.

 
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Stupid question for you, when you say runner you mean the portion that runs from the cylinder head to the Cat? And the flange is the portion the flat portion that bolts to the head? And finally, my father in law is a gearhead and said if that apparent crack were actually the leak that the area would be covered in carbon. Thoughts?

Thanks again!

 
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yeouch!

yeah, gasoline is made of carbon molecules and other molecules that are released after the combustion process, so you will find carbon in there, as you would in any exhaust system for internal combustion engines. Not that it matters much, it's cracked, period. Heck, it's simply separated completely...


welding them does not yield long term solutions, they are connected to the engine, it will vibrate and crack again in the short term.

replace.

 
Rep Power: 518

Holy cow.....Did he see that picture, or is he blind?
The crack is pretty freekin obvious if a person has at least one working eyeball.

FWIW the flange is blackened with carbon.
Run the engine and you should be able to feel the exhaust pulses at that crack, and smell the rich aroma of fresh raw exhaust