I have a 97 Prelude, automatic, just over 100k on the car. It makes a weird noise when the engine is slowing down from between about 1700 to 1000 rpms. If I rev it up to 2000 rpms and let it drop back to idle I hear the sound every time. Also if the throttle is held open the exact right amount, around 1000 to 1200 rpms, the sound can be heard constantly and consistently. The CEL is not on. I recently adjusted the valves because I thought they were the cause of the noise but I was wrong. Two of the valves were way out of spec and I am assuming that could have been the initial cause of the noise but not sure now. Its a kind of clattering noise, maybe a slapping, not very loud but loud enough for me to be concerned. I am pretty sure it is coming from somewhere in the head maybe the cams or valve train somehow? Any of you have any ideas? What should I check and look for? Any and all insight is appreciated.
yeah it's really weird sound. I was gonna adjust my valves this weekend to see if that was the case, but seeing yours is still doing it makes me worry now. I will still adjust my valves and check it out.
OK, here's the vid. At around 11-12 seconds, 14-15s, and 20-23s it is making the noise. That is me reving it and letting the revs drop slowly. I kind of held it steady as it dropped for the 20-23 second part. I think it does it a little at the end too.
ya the bolt got stuck and broke off he said it crossed thred and thays why they got a replacement engine so is there a why to fis it are do i need a new crank
OK, here's the vid. At around 11-12 seconds, 14-15s, and 20-23s it is making the noise. That is me reving it and letting the revs drop slowly. I kind of held it steady as it dropped for the 20-23 second part. I think it does it a little at the end too.
They are called lost motion assemblies. Lost motion assemblies are devices that really just supress the noise of the VTEC rocker arm rattling around when not in use. On occasion the go and when they do they cause massive rattling in the engine. I had a b18 that had broken LMA's and it sounded like a horrid valve tick; kinda likke what you have in the video but not as aggressive.
Okay, there are a few things going on there from what I can hear.
1) you need a valve adjustment or fresh oil, or both VERY BADLY!!!!!!!!!!!!!!!!!!!!
2)I hear the noise as the revs fall. I'm gonna say that's a bad autotensioner. If you are more than 80k miles and the timing belt hasn't been replaced yet.....there it is.
Also, if you adjust your valves, and they don't quiet down, either you did it wrong, or your Lost Motion Assemblies are bad.
To me though, that sounds like a T-belt slapping around, like it is slack. The infamous autotensioner noise is always heard on the falling revs or upon downshifting, so it fits your circumstances.
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I hope for your wallets sake it is just the tensioner or valve adjustmetn man as the lost motion assemblies are fairly expensive i think, i know they were for the GSR. Dunno about the lude man. Also the LMA'S need to have the head dissassembled to be remover and replaced so lots of labour on top of the intial part purchase.
I hope for your wallets sake it is just the tensioner or valve adjustmetn man as the lost motion assemblies are fairly expensive i think, i know they were for the GSR. Dunno about the lude man. Also the LMA'S need to have the head dissassembled to be remover and replaced so lots of labour on top of the intial part purchase.
Sorry about that video I posted earlier today. I was at work and I thought that was the same video I've seen in the past. It looks like someone took it down though.
The noise in YOUR video is the tensioner/timing belt. It's pretty common and should be done relatively quickly.
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Easy fix?, How much are they?
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