Hi,

I am trying to help my parents out with a new problem that has popped up with their '97 Honda Accord Wagon. I'm not a Honda person so I'm hoping some of you might be able to give me some insight into what they might be looking at here. My folks are in their 80's and are easily taken advantage of so I'd like to try to isolate this issue before sending them out for an estimate.

I've put a recording of the sound it's making here.
http://www.youtube.com/watch?v=R4wUAVuOx-k

I had the car out for a 150 mile high speed trip last night, and it made that sound maybe half a dozen times, sometimes for as long as 10 seconds. It only occurred under one condition, when the car was revved fairly high (maybe 4K or so) and then I took my foot off the throttle. As the RPM dropped it made this very loud rhythmic banging sound accompanied by a pretty noticeable vibration which seems to be emanating from the center of the underside of the car. It's hard to say for certain though.

If the throttle is depressed again then the sound immediately stops. I have thus far been unable to reproduce the sound while sitting with the car in park, but I don't think that completely vindicates the engine. I checked the tranny fluid level, and it appears to be correct. There are no fill marks just a checkered zone and the fluid is at the top of that. It is still red, although it smells a bit burned to me (mind you I'm not an expert at reading ATF my cars have manual gearboxes). Oil level I think is normal. Again there are no words on the stick, but rather two little dots and the level is at the upper dot. Please tell me if this is not correct.

The car has 93K miles. The engine blew a seal at 80K and was bled dry, and it got a new factory engine at that time, fortunately under warranty since it was a recall that they'd never been informed of.

I've never heard a sound like this before. Does it ring a bell with anyone? Tranny, CV's, suspension, bearing maybe?

Thank You for your help!!

 

it sounds like 90% u have a spun bearing. Drain the oil, take a magnet and stick it in the oil see if you can see metal shavings sticking to it . And the worst thang that can happen is your burning to much oil and you might be melting a piston this can blow the engine, melted pistons normally use 1qt of oil every 50-100 miles. So that sound is really bad your best bet is to motor swap a new rebuilt motor . If it's knocking that bad the damage already happen . Good luck

 

You could be dealing with a defective Timing Belt Tensioner. This little beauty can make a slapping / knocking noise upon RPM decelleration in neutral only. It would (however) be more inclined to be heard directly in front of he driver (L/side of the engine)

Sorry, but it's hard to pull the noise out of the background noise.

P

 

It doesn't sound like something internal with the engine or it would happen all the time or start/stop when going from cold/hot.

IMO this is a trusted mechanic worthy issue but go there armed with the knowledge that it has to be something with the tranny or timing belt due to it only happening when you let off the throttle while under heavy load.

Keep in mind you could always drive it somewhere else for 2nd opinion so that will give you some leverage as well.

 

If it helps, the sound in question starts at about 17 seconds and lasts for about 3. Is the tensioner spring actuated or does it operate with hydraulic pressure? You say it happens in neutral only. When it happened on the highway it was in drive. Are you saying that this alone would disqualify that diagnosis?

 

I'm going to try an oil change when I get home. I gather you are talking about the small end (rod) bearings right. Are the shavings you are saying to look for from the rod? I can't imagine the bearing would be ferrous. This would be a very distressing failure with what we were told was a "new" factory engine less than 10K miles ago.

Was I correct that the oil is meant to be filled to the upper dot on the stick?

 

just a shot in the dark but anyone think it may be the carrier bearing or something wrong with the cv shaft?

 

I listened to the audio, and it really sounds like a loose splash shield fluttering in the wind. I cant begin to tell you how many cars I see going down the interstate in which you can visibly see their front splash shields flapping away. It didnt sound much like a hard, or metallic knock (at least on my speakers) so i wouldnt immedietly suspect engine, or drivetrain mechanical.

Just take a quick look under the car to make sure the splash shields are nice and tight. -At least thats a FREE fix if im right : ). As far as it only making the sound on decel after 4K rpm, maybe the pull of the car, or the twist of the subframe allows the shield to flap only under those conditions. Give this a try since its a simple diagnosis.

Besides if they just got a new engine, the previous mechanic most likely took off or at least loosened the shields to get at certain bolts, so its a possibility. And also (not to say your parents are bad drivers...) but older people tend to hit curbs, parking stops ect. so maybe a shield got caught when they backed out and the noise started when it got too loose. Good luck!