lateralus

iTrader: (1)

I just started noticing a weird sound that is like running liquid when I crank the car or give it gas after not giving it any for a bit....

It is most noticeable when I am starting back up from red-lights after sitting for a minute or two...

The sound seems to be coming from back behind the glovebox, and definitely sounds like some kind of running/sloshing liquid. If I slowly give it gas with my foot on the clutch, I hear the sound for a couple of seconds when the engine gets around 2k rpm.... Other than that, the car is driving fine and I don't have any warning lights on.


Anybody heard the same noise or know what it might be?

Thanks

carbonRX8

iTrader: (1)

Air in yer coolant lines. There is a method to flush this on here some where.

War eagle.

Bigbacon

iTrader: (4)

my car has always done that.

lateralus

iTrader: (1)

Is it going to hurt the engine to drive before I get it flushed out?

carbonRX8

iTrader: (1)

Too little coolant could, but my understanding is that driving normally with these air pockets will do no harm.

lateralus

iTrader: (1)

Good deal, I was planning to change out my coolant anyway pretty soon since I bought it used and don't know what the guy before me did, so if its not gonna cause a problem I'll probably just top it off for now and be sure to flush it good when I change it.... Thanks


And hell yes War Eagle. You from around Auburn?

carbonRX8

iTrader: (1)

Search for the thread, but I was never quite able to get rid of the sound completely even when I followed the method to do so.

Graduated Auburn in 1995. Love that place.

lateralus

iTrader: (1)

Well, I haven't gotten around to flushing out the coolant yet, and it looks like I may have to go ahead and do it soon because that noise has gotten a lot louder. Especially on start-up...

If the car hasn't been driven for a while, when I crank it I can now hear a definite pretty loud flowing liquid sound from around behind the glove box. The only thing that has changed is that it has gotten significantly colder outside. So unless temperature would do something to it, I don't know why it has gotten louder...

Does this still just sound like air in the coolant line or could it maybe be something else?

-Thanks

Ross Roberts

I have experienced the same sound,

Kind of a slight sloshing/bubbling from the same area, engine is getting rebuilt this month so it is something i will ask them to take a look at,

If I hear anything in regards to this i will let you know.

RIWWP

iTrader: (2)

Ross, that guy asked that question 3 years ago and hasn't been on the forum in over a year.

The diagnosis above is correct though, it is simply coolant rushing in the heater core. You can have the dealer fix it by installing a set of baffles in the heater core, but it's going to cost you an arm and a leg. There is zero harm from the noise, zero performance impact of either your engine or your heating system.

It's present on most Mazdas from that age, and all RX-8s that haven't have the baffles installed.

Ross Roberts

Hey, thanks for the update, guess I should look at the post date more prudently in future!

psyentific

Yeah, I had this problem too - Rotorsports in Santa Clara, CA installed an official Mazda retrofit part, a brass orifice that goes into one of the coolant lines somewhere, and the problem was solved. Orifice is about the size of a nickel and was under $20.

I have the p/n somewhere & will add it later.

One thing that disappoints me about this site is that there's no attempts by admins to merge similar threads, plus there's no attempt at keeping an updated summary on the more popular threads. I guess that's two things...

psyentific

F100-61-E09
ORIFICE, HEATER HOSE

USD $5.66 online at many locations - here's one:

ORIFICE, HEATER HOSE. HEATER. Mazda RX-8 (2004 - 2008) # F10061E09

I'm imagining that the install included some bleeding of the coolant system as well, but I'm not sure what exact method they used. Anyone know if there's a method specified in the Mazda shop manuals?