heat exchanger buzzing

[richmccolman]

I think that I've isolated (via stethoscope) the buzzing noise I'm hearing from my coupe when revved to 4,000 rpm or above to (ta da) - the heat exchanger. Miles has suggested that such noise could be due to a loose or broken aluminum fin inside.
However, one thing that I haven't mentioned is that it appears the car's heat exchanger has no sound deadening material whatsoever coating the outside sheet metal. (I'm guessing that a previous owner must've had the original sound deadening material sandblasted off.) I'm wondering if the lack of sound deadening material could be contributing to the noise.
Also, if I were to attempt to re-coat the heat exchanger, what would the experts here recommend? At one point, I think that someone suggested the heat exchanger's sound deadener was essentially the same as automotive undercoating. The concern I'd have, though, is whether the heat generated by the undercoating would cause the undercoating to really stink when the car is running. (Automotive undercoating that I'm familiar with tends to be stinky stuff as it is, even without getting heated up.)
Any thoughts on whether coating the heat exchanger could dampen the buzzing? And what about using undercoating?
Thanks,
Richard

[Eric Geiger]

I sandblasted off all my heat coating and have my header and heat exchanger ceramic coated.  I have no buzzing noises.  I don't think your heat coating being missing is going to effect anything.   Also I think undercoating is a bad idea as it would never hold up to the high temperatures its exposed to.
Eric J. Geiger
---------------------------------------
PRG Nocturne
XXX-XXX-XXXX phone
XXX-XXX-XXXX fax
XXX-XXX-XXXX mobile
egeiger@...
www.prgnocturne.com

On Oct 3, 2012, at 6:35 AM, "richmccolman" wrote:
I think that I've isolated (via stethoscope) the buzzing noise I'm hearing from my coupe when revved to 4,000 rpm or above to (ta da) - the heat exchanger. Miles has suggested that such noise could be due to a loose or broken aluminum fin inside.
However, one thing that I haven't mentioned is that it appears the car's heat exchanger has no sound deadening material whatsoever coating the outside sheet metal. (I'm guessing that a previous owner must've had the original sound deadening material sandblasted off.) I'm wondering if the lack of sound deadening material could be contributing to the noise.
Also, if I were to attempt to re-coat the heat exchanger, what would the experts here recommend? At one point, I think that someone suggested the heat exchanger's sound deadener was essentially the same as automotive undercoating. The concern I'd have, though, is whether the heat generated by the undercoating would cause the undercoating to really stink when the car is running. (Automotive undercoating that I'm familiar with tends to be stinky stuff as it is, even without getting heated up.)
Any thoughts on whether coating the heat exchanger could dampen the buzzing? And what about using undercoating?
Thanks,
Richard

[richmccolman]

Thanks, Eric. The undercoating applied to the heat exchanger seemed odd to me too, due to the heat (like putting tar on a hot frying pan). That's one reason I asked. Since someone (can't recall who at the moment) mentioned undercoating, I figured I'd check. I also appreciate the info about your heat exchanger without the factory heat coating not buzzing.
Richard

--- In
anzhonda600owners@yahoogroups.com
, Eric Geiger wrote:
> I sandblasted off all my heat coating and have my header and heat exchanger ceramic coated. I have no buzzing noises. I don't think your heat coating being missing is going to effect anything. Also I think undercoating is a bad idea as it would never hold up to the high temperatures its exposed to.
> Eric J. Geiger
> ---------------------------------------
> PRG Nocturne
> XXX-XXX-XXXX phone
> XXX-XXX-XXXX fax
> XXX-XXX-XXXX mobile
> egeiger@...
> www.prgnocturne.com On Oct 3, 2012, at 6:35 AM, "richmccolman" > wrote:
> I think that I've isolated (via stethoscope) the buzzing noise I'm hearing from my coupe when revved to 4,000 rpm or above to (ta da) - the heat exchanger. Miles has suggested that such noise could be due to a loose or broken aluminum fin inside.
> However, one thing that I haven't mentioned is that it appears the car's heat exchanger has no sound deadening material whatsoever coating the outside sheet metal. (I'm guessing that a previous owner must've had the original sound deadening material sandblasted off.) I'm wondering if the lack of sound deadening material could be contributing to the noise.
> Also, if I were to attempt to re-coat the heat exchanger, what would the experts here recommend? At one point, I think that someone suggested the heat exchanger's sound deadener was essentially the same as automotive undercoating. The concern I'd have, though, is whether the heat generated by the undercoating would cause the undercoating to really stink when the car is running. (Automotive undercoating that I'm familiar with tends to be stinky stuff as it is, even without getting heated up.)
> Any thoughts on whether coating the heat exchanger could dampen the buzzing? And what about using undercoating?
> Thanks,
> Richard