Heater core?
 

Hello all. I own an 88 gxl and I noticed the other day that when I turn the heater on specifically on the hottest setting I can hear the water flowing under neath the steering column to the right. I don't suspect any leak but I'm concerned as to why it's making this sound. I believe it's coming from the heater core. Is this normal? thanks in advance---------Ren

You might try this question in the 2nd Gen Specific forum to see if someone there has experienced it, but here goes;

The heater core in my 84SE and 80LS are such that they never have any air bubbles in the lines, so you can't necessarily 'hear' the water running through. If there are bubbles in the heater lines going to your core, then you may hear the bubbles going through, but not the water, IME.

Now, to find out why the bubbles are there, have you checked your radiator coolant level recently? Even a slight amount missing from there can cause bubbles in the lines going to the heater, which will then travel through the firewall and sound like they're under your dash. My 84SE has a heater core with a water valve that controls the incoming water flow. This valve piston is connected to the rotary dial on the dash that goes Hot/Cold, and when in the Hot position, opens the water valve piston to allow heated water from the lower radiator take-off to enter the heater core. If your coolant level is low, top it off (when cold, don't burn yourself by removing when hot) and then see if you still hear the water movement.

Also, be sure that your overflow tank is to the Full line, so that when the radiator cools off, it will draw the fluid from the overflow tank back into the radiator to replace the fluid level, otherwise, you'll continue to get air spaces in the radiator until it heats up. This may help to explain why you may hear the bubbles only when the car is cold (if this is your case).

I have bypassed the heater core on my 84SE because the piston valve seals went out and started leaing hot coolant on my accelerator foot on cold mornings. Then, it started doing this on hot mornings, combined with steam coming from the dash vents - a very common problem with 1st Gen RX7's, and maybe just as likely with your 2nd Gen.

Hope this helps,

It's normal! The valve that controls the coolant going in and out of the heater core is inside the car, and right next to the core. I is completly normal! As long as there are no leaks or steam that Longduck described, you are fine. Hope it helps.

You guys are awesome:) thank for your responses------ren