I have an 04 Accord EXV6 with 237K miles. I have recently replaced shock absorber assemblies and all 6 motor mounts / transmission mounts, which resolved most of the loud “clunking” noises. However, I now have more of a “rattle” sound which I hear when one of three things happens…First, when the engine is started (typically when the engine is cold). Secondly, when shifting between park, reverse, and drive (also, more common when engine is cold). Lastly, when driving over rough roads or potholes at slow speed. The sound is the same in each of the 3 conditions, and appears to be coming from the right side. It doesn’t seem to me that any bushings, control arms. etc. would be the cause since the same sound is heard during startup or gear shifting while the car is sitting still. I have reached the end of my expertise, and any help is appreciated.
Look at your muffler clamps!
+1 on muffler clamps.
Also look at the muffler’s heat shields. They often rot through where they are mounted so you may not be able to mount it properly.
If you find one, just snug a large hose clamp* around it.
*Home Depot plumbing department.
Motor mounts are typical problems as a car ages.
Thanks for all the comments thus far…hope there are more coming. I checked muffler clamps, all good. Motor mounts / transmission mounts have all been replaced in past 3 months, and they were definitely in need of replacement. Some of the other hard “clunks” were resolved when the mounts were changed, now the only sound left is the low pitched “rattle”, or “rumble”. It happens when I startup the vehicle, typically only when it’s cold, and when driving over rough road, speed bumps, etc. I am about to change some of the steering / suspension parts, including lower control arm bushings, as they are shot. I am hopeful that will resolve this, but I am stumped as to if or why that would make a sound when the car isn’t moving. Any more suggestions, keep them coming. Once (if) I figure it out, I’ll definitely post the resolution. The picture attached is of the front right control arm bushing, i believe it shows the cracked rubber. Does anyone think this could cause a rumble sound when the car is started?
Get under the car with it well secured against rolling, and vigorously shake all the various components and subassemblies including the sway bars and exhaust system. The sway bars have been twisting within the rubber bushing that hold them to the chassis for eight years now. It’s entirely possible that they’ve worn the holes big.
Post back with your findings.
Also realize that vibrations travel. Anything, including a sway bar bushing, could be your culprit.
I can’t tell from the photo, but cracks in the periphery of a bushing are more often than not only on the surface and don’t affect the integritu of the bushing.
This morning, I removed the wheel, and while the car was being held by jack stands I took a pry bar and raised the lower control arm on the side in the picture and wedged some shims into that space, started the car, and the sound seems to be less prominent. Either way, the bushings need replacing, which I will do. I am attaching another picture showing the amount of separation, they are definitely cracked all the way through, similar to what the motor mounts looked like. On another note, the swaybar bushing seemed to hold the swaybar tightly, no apparent rattling / movement there.
OK everyone, I hope you’re still around to listen to this. I finally thought this through and realized that posting a video of the sound might help, so here’s a 3 second video. If you can ignore the beeping, note the sound just after the turning over of the engine when it’s being started. You should be able to hear the rattling, or knocking, in question. This sound is the same I hear when driving over rough roads, but I thought it best to show it while car is not moving. I have more videos I could post that are a little longer, but wanted to start with this. Be sure to turn up the volume. Appreciate all comments.
Is this an automatic?
Here’s one stray to grab onto: maybe the bolts that hold the drive plate to the flywheel have walked loose and there’s now play in there somewhere? So every time you start or change speeds, it kinda flops around a bit? Not saying that’s it but it may be worth checking.
You should be able to inspect those bolts by finding the inspection hole and manually turning the engine so you can look at them.
it is automatic. hate to sound dumb, but does an automatic have a flywheel?
Well, you’re right - technically it doesn’t because it has a the torque converter but serves a similar purpose. The torque converter is the part that had the teeth on the edges, much like a flywheel, so the starter can start the car. It serves a similar purpose, among the other things it does.
The torque converter is bolted to the drive plate. Those bolts could have loosened.
I know it makes for quite a weird intermittent racket when that happens.
OK thanks. So, you’re saying I can view this without having to take anything apart, is that correct? As far as the rattle goes, it’s about as annoying as can be, and is pretty much continuous when driving rough road. I just thought it was important to point out that it also happens when the car is not moving, so as to eliminate suspension issues.
Yeah, I think the noise being there with you sitting still pretty much eliminates it being suspension related. It would be hard to imagine your car shakes that badly that the suspension is affected to the point of it making noise.
I’m pretty sure you can get to the inspection hole on top of the engine. It usually has a rubber plug in it that just pulls out. From there, you manually turn the engine and watch for the bolt to appear in that hole so you can make sure it is indeed tight.
Again, I’m not suggesting this is definitely ‘it’ but do know a loose driveplate bolt can make some weird noises so it is worth a look, if you can get to it easily.
Found a couple plugs on the passenger side of the engine, hard to see in them. I am hoping to get more suggestions on this so I’ll have more than one to check out once I have a chance. If the longer (driving) video will help, I’ll post it.
By the way, I am far from a mechanic type, I would call myself more of a “figurer outer”, and get satisfaction in doing so. So, how is it that I turn the engine? Do I remove the serpentine belt and turn the crankshaft bolt?
Just turn the crankshaft bolt.
Most of us are “figure outers” - I try to be, anyway.
OK will do. Also, I am hoping to get more comments from my video, I’d like your thoughts. My original post got several comments, do you think I should start a new post to get more input? I’m not sure how you, or any of the other commenters, are notified. Any advice appreciated.