1996 Honda Accord Engine Knocking

[kschachn]

I'll try and keep this short. I just (a week and a half ago) acquired a 1996 Honda Accord (4-cyl F22B2 non-VTEC engine, 126,000 miles) and it has either just developed or had a knocking sound in the engine. It is a long story but I was unable to listen to or see the car before it was purchased (a gift from an in-law for my daughter). The car has had excellent maintenance on it by the original owner, all scheduled work was done (and documented) and the oil was changed an average of every 3200 miles (conventional Trop-Artic 5W-30). This week I adjusted the valves, replaced the spark plugs and changed the oil to GC and a M1 filter.

Anyway, the noise is pretty loud. It is more noticable when the engine is cold (it sounds diesel-ly, like piston slap) and it does NOT disappear when warm - but it is reduced a lot. I took it into the Honda dealer yesterday for a diagnosis and they said it sounded like piston slap in the #4 cylinder. I tend to agree but the only thing that has got me unsure is that the sound doesn't go away when warmed up. This along with the fact that the previous owner took such good care of the car. Can piston slap happen even with good maintenance and can it still be heard after the car warms up?

I need to make a decision soon. Either we are going back the seller and look for a refund/adjustment or I'm going to live with it. It sounds junky though in the morning, like a car where the owner (now me) never changed the oil. And I hate being seen in a car like that.

When I adjusted the valves the engine looked VERY clean inside. Some varnish but no deposits whatsoever. It doesn't appear to use any oil and the compression test I did came out 189, 184, 185 and 190 - well within the Honda specs. I just can't believe it is something due to poor maintenance.

I've been poking around on it for three days using a stethoscope and I can't pinpoint the source of the noise. I'm pretty much with the dealer's diagnosis that it is coming from the block, and specifically the #4 cylinder.

Any advice is appreciated

 

[mechtech2]

You'll never be sure or happy with it.
Get another car, unless this one is real cheap.

 

[Bulli]

I HAVE a 1995 HONDA accord with 120k miles i am the second owner and i bought it in November and i also heard a engine noise. pretty big after i changed the oil. the guy probably pu tin thicker oil to quiet it down. I also took the valve cover off to replace a leaking spark plug seal and found the engien to be clean. It does not use a drop of oil. I adjusted my valves myself and i might did that wrong. i got a upper valvetrain rattle tick again. Also i hear a knock when i listen down into the oil pan. Proabably a slight rod knock. My engine runs fine though. i speed with it alot and i see no problem. Pretty quick car but the noise does worry me. 5 months in now and since its getting warmer i am planing to diagnosing it.


if u can post a video of the noise that would be great i can compare it to mine and i will do the same to you.

ps. did honda charge you anyhting to diagnose the problem?


I dubt it is piston slap since that goes away when the engine is warm and all metals have expended. I know if its the last cylinder # 4 the oil pump is crapping out on you.
Be sure to check you oil pressure. I dont know how but i want to do it sometime.
Also i switched from 5-30 to 10-40 and the knock is reduced by alot.

my i can sadly say i have 3 noises coming from the engine and my clutch (manual) is weird.

If there is no worn bearing or nothing serious i am happy i made the purchase. 2300 for the car. 200 tune up and 2000 exhaust.

 

[PT1]

Originally Posted By: kschachn
This week I adjusted the valves, replaced the spark plugs and changed the oil to GC and a M1 filter.



Did it make this noise before you adjusted the valves? Or added the GC as that may be too thick of an oil. If so try a thinner oil like PP to see if it changes. Double check your valve adjustment and swap the coils from #4 to #1 and see if the sound moves to #1.

 

[kschachn]

OK, here is a video of the engine. You can hear the noise especially towards the end. It is lounder when the engine is under load but I wasn't able to do that by myself:

http://myfreefilehosting.com/f/e11dcc3bc9_17.54MB

To answer a few of the questions, it cost me $55 at the dealer which was 1/2 hour of their time. They spent considerably more time than that, several techs came over to listen to the noise.

It did make the noise before I adjusted the valves. I can't swap coils on this engine (it is a distributor) but I could swap wires at the cap.

I could check the oil pressure. I have a gauge but the sending unit is on the upper back side of the block - not real easy to get to since my ramps are too tall (they hit the bumper) and there isn't any convenient place to put jack stands without removing the underside splash shield. But I was thinking of doing that anyway so I'll see what I can do.

 

[ThirdeYe]

I know in my Integra I always thought I had piston slap. It sounded almost like a diesel when it's cold, and had great maintenance by the previous owner (I have all of the receipts from every oil change at Acura) and there's no varnish, sludge, etc., and returns great gas mileage and comes back with stellar UOA's every time thus far. What I'm starting to think is that maybe it's my fuel injectors. I hear Honda fuel injectors can be really noisy and make almost a piston-slap like noise. A really loud clicking sound, that's more pronounced when the engine's cold but will still be there when warmed up. That would be my slightly uneducated guess, I could be wrong though. I would think that if my engine was piston slapping it would show up in my UOA's but the aluminum came back as no wear at all.

 

[kschachn]

ThirdeYe:

I can hear the injectors for sure. They are loud - but not that loud. This sound (as you probably heard on the video) is more of a deep knock. A lot like a diesel sounds.

I know that is what you said your car sounded like, but geez, these would have to be the mother of all noisy injectors if that was the case.

 

[ThirdeYe]

Yeah, I just listened to the video and it sounds a little different than mine... I can try to make a recording of my engine sometime so you can see what mine sounds like, if that would help at all.

 

[TexasHonda]

I have heard a similar noise on other cars. It does not sound like a rod knock (too high pitched). A rod knock has a deep resonant sound that is umistakeable. It could be piston slap, as you suspect.

Have you tried using a heavy weight oil, perhaps Sae 20w-50, to see if that quiets the sound? Heavier oil will help a rod knock, but may not help w/ piston slap.

Perhaps a loose exhaust pipe, catalytic converter, or heat shield could cause such a noise? Might be worth putting up on ramps and inspecting exhaust system.

My daughter's 1997 2.2CL has a somewhat similar noise that I notice on hard acceleration in first gear. A hard rattle that occurs at high rpm, hard acceleration in 1st gear (manual trans). The car runs perfectly otherwise, and I don't hear anything at idle or cruise.

You might try putting the car under load, pulling a steep hill while staying just above shift-down point. Noise in this condition would suggest something loose in the engine.

good luck

 

[RH+G]

That dont sound bad at all. All F-series motors are kinda noisy. I would triple check your valve adjustment.

 

[ThirdeYe]

I made a video of my car at warm idle, I'm uploading it now. Unfortunately the microphone on my digital camera isn't the greatest so you hear a lot of other ambient noises such as the accessory belts, fans, etc. but it might still help -shrugs-, I'll edit this when the video is done uploading. I don't think your engine sounds bad though, for what that's worth. These aluminum block engines tend to be a lot noisier than their iron brethren.

 

[ThirdeYe]

Edit time expired, d'oh! Here's the vid:
http://www.youtube.com/watch?v=xLl12acX0nA

Hope it helps somewhat, sorry for the bad mic. Valves were last adjusted about 14,000 miles ago. Checked valve clearance about 3,000 miles ago, all within spec. I think most of the noise you hear in the vid of mine is the fuel injectors. Also, my mic makes the noise a lot louder than it really is. Listening to it in person, it's actually fairly quiet. The mic just seems to amplify the noise.

 

[addyguy]

Its a Honda. It doesn't matter what noises the engine is making, it will will run forever, even on no maintenance. I don't how many Civic and Accords I've seen that have next to no oil in them, and they keep going strong for years. Or engines that are redlined all-day, every day, and don't complain.

Don't worry about it, and enjoy the great mileage it will get...seriously.

 

[PT1]

Originally Posted By: RH+G
That dont sound bad at all. All F-series motors are kinda noisy. I would triple check your valve adjustment.


+1 That sounds like top end or exhaust valve knock to me. Like the other guy said go get some Valvoline 20w50 (< $20)and try it in there. But check your adjustment first. My brother used 20w50 in all his older accords to shut them up.

 

[Bulli]

http://myspacetv.com/index.cfm?fuseaction=vids.individual&videoid=32055018

there is mine.
let me know if it doesnt work for non myspace users

 

[ThirdeYe]

Sorry, this is a private video.

 

[kschachn]

Thank you for all the advice. ThirdeYe, I agree, your noise is mostly injectors - pretty normal stuff.

I stopped by Autozone after work and picked up four quarts of Castrol 20W-50. Wow, I half expected to need a grease gun to get that into the engine, but it went in. The car sure noticed the difference, it seems a lot more sluggish and slow.

But alas (or maybe good) it made little or no difference in the noise. It's hard to tell but I would say that if the knocking was a "5" with GC then it is a 4.5 now - no better than a 4 for sure. So whatever it is the oil doesn't seem to have made much of a difference.

This weekend I am going to tear the exhaust system apart and check it out. I just want to eliminate that as a potential cause for the noise. At this point I don't really know what else to do.

So any final thoughts if the oil didn't make any difference?

 

[Bulli]

you can always take the oil pan off and check for loose rod end caps and such.

 

[-Clayton-]

That noise sounds horrible, I'll do you a favor and take the car of your hands for $100.




Seriously though that doesn't sound like anything to be concerned over, Ditch the 20w50 run some good FI cleaner through it and call it a day.

 

[Quest]

saved the avi file and repeatedly listened to it a few times.

Sounds like a rod knock or piston slap.

Don't discount the possibility of either 1 of the 2 mentioned ones for it may still happen to engines that was, at one point in their serviceable life, been neglected somewhat.

If thicker oil in cold startup doesn't help in taming (buffering) the rapping noise, it's very likely a piston slap. Normally on Honda cars, unless the engine was assembled wrongly (with wrong diameter pistons), otherwise, the likeliness of experiencing a single piston slap is rather remote. That being said, however, abuse/neglect such as heavy load when engine block is dead cold, improper viscosity oil used(during cold start) and/or excessive piston skirt to cylinder clearances to begin with, will worsen over time and nothing can help but to do a partial engine disassembly in order to find out. Also: pistons will lose their ability to expand/contract as mileage accumulates (for those expand-to-conform type) and that may case rapping noise also.

Good luck! also consider Bulti's advise of pulling off the pan and perform a quick rod bearing clearance check.

Q.