vibrations/rattle around 3-4k

[SharpAndy]

I am a Honda tech, and my project this week has been a 2023 integra with the rattle at 3500-4K. This vehicle is a manual transmission, and it only happens at that RPM range. I just found it yesterday. We found it to be the heater core rattle against the heater box. Also found that the heater box’s mount was broken. The whole dash is out, and we are waiting on parts now. You can see if this is your issue by revving the car to the point it makes the rattle and have someone wiggle the coolant lines that come out at the heater core.

I noticed that my Integra JUST started doing that about two days ago. So I now have three completely different squeaks and/or rattles...this new rattle sounds like it's coming from under the dash and occurs between 3000-4500 rpm. There's still the squeak from the bezel around the HUD, and the hatch rattles. So it's definitely not a quiet ride at any given time. I guess I just couldn't hear the newest one until I took the roof bars off, because they will drown out even your most inner thoughts.

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[bpebler]

number 9 is the heater core pipe retainer. they call it a stay. The top tab was broken off allowing the pipes to touch together.

Is this also to say that it may likely happen again with the same kind of fix & parts until Acura/Honda find a better solution towards a forever fix?

 

[starter_hart79]

Is this also to say that it may likely happen again with the same kind of fix & parts until Acura/Honda find a better solution towards a forever fix?

In my case I don’t think it was a part issue. I think it was an assembly issue.

 

[zachristo]

I’ve found that turning the heater on full for 10 seconds or so then returning to the desired temp alleviates the rattle usually for the length of the drive. That will hold me over to the next service where I can bring it up with the dealership. Maybe that trick can help others being driven crazy by this.

 

[starter_hart79]

I’ve found that turning the heater on full for 10 seconds or so then returning to the desired temp alleviates the rattle usually for the length of the drive. That will hold me over to the next service where I can bring it up with the dealership. Maybe that trick can help others being driven crazy by this.

That to me sounds like an issue with the blend door or the blend door actuator.

 

[AceRaiden]

Hey guys, I have the same issue on my 22 Si. Goes away when I do the full heat trick. Did you ever find a solution

 

[starter_hart79]

Hey guys, I have the same issue on my 22 Si. Goes away when I do the full heat trick. Did you ever find a solution

Do the same thing, but this time start with the heat on the lowest setting and keep the blower on the lowest setting too, and rev it up. Then turn heat to highest setting with blower still at lowest setting. I think your issue is a blend door rattling in a certain location. I don’t think it has anything to do with the actual temperature or the blower action. Could be wrong though.

 

[AceRaiden]

Do the same thing, but this time start with the heat on the lowest setting and keep the blower on the lowest setting too, and rev it up. Then turn heat to highest setting with blower still at lowest setting. I think your issue is a blend door rattling in a certain location. I don’t think it has anything to do with the actual temperature or the blower action. Could be wrong though.

Good idea! Will give it a try and report back.

 

[Palut]

You can get to the blend door actuator mechanisms with a little work. Removing the lower driver side trim and knee airbag gets you in on that side, while removing the glove box and lower dash trim gets you there on the passenger side.

My car had a lot of play in those mechanisms when I explored down there, but I didn't actually make any adjustments to them and my car is quiet. I may have been lucky.

 

[starter_hart79]

You can get to the blend door actuator mechanisms with a little work. Removing the lower driver side trim and knee airbag gets you in on that side, while removing the glove box and lower dash trim gets you there on the passenger side.

My car had a lot of play in those mechanisms when I explored down there, but I didn't actually make any adjustments to them and my car is quiet. I may have been lucky.

For a 22 i would just take it back to the dealer. But it helps the dealer when you go in with all the info possible.

 

[Rz2Gd]

I am a Honda tech, and my project this week has been a 2023 integra with the rattle at 3500-4K. This vehicle is a manual transmission, and it only happens at that RPM range. I just found it yesterday. We found it to be the heater core rattle against the heater box. Also found that the heater box’s mount was broken. The whole dash is out, and we are waiting on parts now. You can see if this is your issue by revving the car to the point it makes the rattle and have someone wiggle the coolant lines that come out at the heater core.

This is exactly what happened to my 2025 ITS and how they had to fix it. Straight from the dealer sale, discovered the noise on the way home, and straight back to the dealer where I was without my new car for almost a month.

 

[4Dparadox]

I am having a similar issue on a 2025 A Spec 6MT… they told me something about needing to remove knee air bag and fixed the heater core rubbing against something… after seeing this tear down to do that job I might live with the rattle. There is low chance anyone is putting that dash back together with care in that time allotment Acura is paying. I would be worried of more rattles coming from broken clips or elsewhere on reassembly. Does this job actually need to take the entire dash apart or was that just done to find the issue?

 

[nateb55]

I am having a similar issue on a 2025 A Spec 6MT… they told me something about needing to remove knee air bag and fixed the heater core rubbing against something… after seeing this tear down to do that job I might live with the rattle. There is low chance anyone is putting that dash back together with care in that time allotment Acura is paying. I would be worried of more rattles coming from broken clips or elsewhere on reassembly. Does this job actually need to take the entire dash apart or was that just done to find the issue?

If the heater core or one of the pipe is rubbing/chaffing on something, I'd be more concerned with it developing a leak over time and possibly causing more damage. Imo I'd take the risk of slightly more/different rattles over coolant damaging any electronics in the area or soaking the carpet

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