thecivicguy2003

Hey everyone,

I have a 2003 Honda Civic LX with the 1.7 SOHC engine with 199k on it. The engine has an oil leak that has gotten worse recently. I wasn't doing a good job of checking the oil level, and because of that the engine ended up getting run low on oil by 2 quarts.

I found out it was low from a noise that developed. It started clattering for about the first minute after starting from cold. At first I thought it was an exhaust leak since I only heard it when hitting the throttle more than about 1/4 or more, and it went away once warmed up. I thought about it more and decided it sounded more mechanical than exhaust. I then checked the oil to find out just how low it had gotten. I filled it back up to the normal level and the sound went away.

I had the oil changed that day to make sure any shavings were removed. I sent a sample of the oil to black stone labs for analysis. They said all of the metal levels in the oil were around the average for that engine.

Almost everytime I cold start the car now I get the same noise, but not as loud. It will happen for about the first minute, but only when hitting the throttle more than about 1/4. After a minute, the sound goes away completely. I've driven it about 5k since then and it has not gotten worse.

I basically have two theories about what is wrong with it. One, a bearing in the bottom end is worn, and the load from 1/4 throttle causes it to surface. Two, something is worn on the valve train and the throttle body opening causes me to be able to hear the sound.

The car is due for a timing belt in 10k, so I'm trying to decide what to do with it. If it's something in the top end I feel like I should be able to fix that by adjusting the valve clearance, which I'd probably do anyway when replacing the timing belt and fixing the oil leak. If it's the bottom end though, I feel like I should skip the timing belt and see how far it goes...

I'm capable of doing the valve adjustment, but I don't have a garage of my own to work in right now. If I had my own place, I would just adjust the valves and see what happens. I have friends with garages and I could ask for space to work in, but i want to have a good idea that it's going to work before asking to use the space.

What do you guys think is up with the car? Any advice?

Thanks in advance!

ezone

You'll have to use your own ears to figure out where the noise actually originates.

Probably cracked exhaust manifold. Usually makes a loud snapping noise during acceleration or load, quiet during deceleration. Plus raw exhaust smell.


Bearing noise/bottom end noise would tend to be quiet and hidden when cold, then get more noticeable as the oil heats up and thins out.

thecivicguy2003

The noise it makes is a loud snapping like sound like you said. It has a sharpness to it like there is metal banging around. Kind of hard to describe.

I know for sure i have some sort of an exhaust leak. It has the typical puttery sound that comes with that. I haven't noticed any smells though.

Its possible the low oil level has nothing to do with the sound. It being low could have been just a coincidence.

I'll have to see if i can figure out where the sound is coming from. Do you have any tips on reproducing the sound while not driving down the road? Maybe hold the brakes while hitting the gas?

Do exhaust manifold crack sounds usually go away after a minute of driving?

Any chance an issue on the top end could cause the sound I'm hearing?

thecivicguy2003

One more thing i noticed. There was one time when i parked the car for about two hours. When i started the car and drove away, the noise occurred. The temp gauge hadn't gone all the way down yet. So i assume the engine was at least a bit warm still. I suppose that could be an indication of an exhaust crack, since the exhaust is smaller an less dense and I would assume would cool down faster than the engine. Although, maybe the engine itself had cooled down enough for the sound to come back. Hard to say.

ezone

Have a helper sitting in the drivers seat to do all that (stand on the brake pedal while tapping the gas pedal briefly to make noise happen, but don't do it more than a couple seconds at a time or you can cause damage to the transmission if you do it too long)
while you hunt for the noise source.

Use a length of tubing held to your ear as a stethoscope, probe around with the free end to locate the area where noise is the loudest....
Yes. The exhaust manifold heats up extremely fast once the engine is running, and as the large casting heats up it also moves and can close up gaps/cracks.

Wankenstein

I was going to suggest the same thing. The cheapo auto stethoscope at harbour fright http://www.harborfreight.com/mechani...ope-69913.html works well too and you get stereophonic sound which, is almost as high-tech as quadrophonic sound that the Beatles recorded in..LOL.

I keep thinking I want to make a recording of the cylinder head area through a stethoscope and use it for sleeping background noise..it's very soothing. Maybe when the day comes that I have grandchildren I will play it for them while they sleep and raise some potential racing mechanics.

Also, couldn't the exhaust manifold (most likely area of leak) be sprayed with soapy water at cold start and look for leaks/bubbles? OP.. use your nose too as you might get some good ole' rotten egg smell from a cracked manifold. However, I'm not sure if that's the case further down the exhaust.

This is why the soapy water test could be limiting. Could have a helper turn the ignition on and off while the exhaust is sprayed and inspected to prolong warm-up.

OP: you could do a valve adjustment in an empty parking lot within an hour as long as you have:

Stock scissor jack to raise driverside front
One jackstand to support driverside front
Socket extension(s) long enough to extend from crank-bolt to beyond driverside wheel well
Correct socket for crankbolt (possibly 17mm or 19mm.. I can't remember)
Feeler gauges
Flathead screwdriver
Wrench for adjusting valves (10mm .. IIRC)
Inch/Pound torque wrench for valve cover gasket (or Ezone's built-in torque by feel sensitivity)

May not even need to raise the driver's side front if the left tire is out of the way enough during full-lock left turn.. to reach the crank bolt through wheel well opening.

ezone

http://forums.stevehoffman.tv/threads/albums-that-were-recorded-for-quadraphonic-sound.342374/

I went to school with a dude who had a quad-8-track home stereo and a few quad tapes.

I once worked for a shop owner who had a quad-8-track in a .....maybe a mid 70s Lincoln Town Car or similar. He had a demo tape, a bird chirping and flying all around the interior of the car.



If manual transmission, I could just stick it in a gear and rock the car to roll the crank to wherever I need it to be.
Used to do this a lot back when manual transmissions and manual valves weren't so rare.

thecivicguy2003

Just realized I never posted where I ended up on this one.

The more I listened to the sound, the more i figured it had to be the exhaust. It wasn't rythmic enough to be mechanical. Also, now that it is summer it makes much less noise.

The sound doesn't really bother me, so I'm probably going to leave the manifold as is for now.

I ended up bringing it to a shop and having the timing belt job done as well as the valves adjusted. The shop didn't notice anything wrong with the head when they looked at it.

Thanks for all the help and advice everyone!