In my 2000 Altima, I recently replaced the engine with a mint, low mileage KA24DE.
While in drive and not moving, I have a rattle from the passenger side floor board. When you accelerate from a stop, it eventually goes away once RPM's increase to about 2500. No noise on the highway. Just low RPM's. If I put the car in neutral at a stop light, the rattle disappears.
I can't find the rattle. Any suggestions. It's pretty loud.
I had a small crack in my exhaust flex pipe, and the resonator, and the exhaust has been addressed: new manifold, new flex pipe, removed resonator. Exhaust is good.
I replaced all three motor mounts as well.
Rattle is still there. I know the nature of the I4 motor, it's gonna shake when engaged to the transmission and it smooths out when in neutral at a redlight.....but I've only experienced this rattle since the recent swap.
In the car, it's fairly loud and sounds like it's coming from the passenger side floorboard. With the hood up, peaking inside the engine bay, sounds like the rattle is coming from the center firewall area....between the engine and the firewall.
I've been chasing this for several weeks now. Any suggestions would be greatly appreciated.
There's a rear engine, a front engine, a side engine, and the transmission mount.
Crap...how did I forget about the tranny mount. Jeeez!!
Whether it's good or bad, I just order it from RockAuto. I'm such an idiot. I'm sure this is it. At least I hope.
Especially since, like most 4 cylinders, I get way more vibration when it's in Drive vs. Neutral or Park. And the rattle only occurs when the tranny is linked to the engine.
Thanks Stanza.
BTW....is this the mount that's basically under the intake and battery?
Crap...how did I forget about the tranny mount. Jeeez!!
Whether it's good or bad, I just order it from RockAuto. I'm such an idiot. I'm sure this is it. At least I hope.
Especially since, like most 4 cylinders, I get way more vibration when it's in Drive vs. Neutral or Park. And the rattle only occurs when the tranny is linked to the engine.
Thanks Stanza.
BTW....is this the mount that's basically under the intake and battery?
Does the vibration increase with revs? if you put it in gear with the brake on does it rattle worse? if it does then your exhaust is touching the frame of the car somewhere especially up front just after the flex there is bracket and there isnt a lot of room there it could be barely touching. In park or neutral my car is smooth in drive even with brand new mounts ALL fwd cars rock back pulling the exhaust slightly forward and in my case touching that darn bracket. My exhaust resonator has been removed also but my exhaust is temporary fixed and it keeps touching the frame in D with brake on but as soon as i hit the gas and get up to speed quiet as a mouse. Hopefully yours is just the mount. The only reason i mentioned the bracket is because you modified your exhaust at the same place i did.
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"Explain to me why lowering it would down grade the car. Whats wrong with a lower center of gravity? If you say ride comfort, I will smack you through my monitor."
Does the vibration increase with revs? if you put it in gear with the brake on does it rattle worse? if it does then your exhaust is touching the frame of the car somewhere especially up front just after the flex there is bracket and there isnt a lot of room there it could be barely touching. In park or neutral my car is smooth in drive even with brand new mounts ALL fwd cars rock back pulling the exhaust slightly forward and in my case touching that darn bracket. My exhaust resonator has been removed also but my exhaust is temporary fixed and it keeps touching the frame in D with brake on but as soon as i hit the gas and get up to speed quiet as a mouse. Hopefully yours is just the mount. The only reason i mentioned the bracket is because you modified your exhaust at the same place i did.
Yeah, it idles in park/neutral with no rattle. Once you're in gear, with the brake, it rattles. It rattles under acceleration until you hit about 2500 rpm's. Then it's gone. Quiet going down the highway at 70 too.
My exhaust guy removed all the heat shields, and super-checked for any rubbing or anything of the exhaust as it was in Drive with the parking brake on. I didn't see any brace under my car near the flex pipe. I'll have to look again tho. There is an exhaust hanger about 2' after the flex pipe, but I never seen any brace or bracket. hmmm....
There is a brace that's about at the rear seat floor boards, that I bent down too. The exhaust was close to that, so I made a little room for it.
With my car running in gear and stopped, there is a big vibration on the power steering reservior and on the fuel assembly "thingu" clear up in the passenger side corner against the firewall under the hood. The assembly is mounted to a bracket with rubber grommets, but it's thumping.
New transmission mount went in today. All 4 mounts have been replaced. Rattle is still there!! I'm gonna pull my hair out. For real.
What is causing the rattle? My mechanic now suggests that the exhaust is pushed too far back, taking all the flexibility out of the flex pipe. Really? Anyone hear of such a thing?
He thinks I should cut an inch out of the exhaust, downstream of the flex pipe, and move the rear of the exhaust more forward.
There are no heat shields on the exhaust anywhere. They have all been removed. The exhaust isnt touching anyhing. Rattle still only occurs when in gear. Mostly at a stop or moving slowly.
Just now on my lunch break, I put the car in gear with parking brake engaged (now it's rattling good), and grabbed the exhaust in the middle of the car. Moved it several inches to the left and to the right. No change in the rattle. Went back to the tail pipe and pushed the exhaust a few inches forward and pulled it backwards...no change either.
Could it be in the tranny? Cracked CAT maybe (CAT material rattling around)?
I can't find hardly anything at all from Altima owners who have had catalytic converters crack or break up and cause a rattle in our cars. Of course, there's plenty on the 2002-2004 Altimas with the 2.5L. Yikes.
Has anyone experienced a broken CAT from our cars? I'm thinking of gutting mine, to see if the rattle goes away. And then either replace the CAT or just put an anti-fouler plug on the rear oxygen sensor to prevent the CEL light from popping up.
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