Neilanrx7

I recently bought an 86 rx7. The add coolant light and buzzer is always going off unless I rev up the engine to about 3500 or if I drive it above about 60 mph. The overflow tank if filled to the top and sometimes after driving coolant is pushed through the top of the overflow out the breather tube. After turning off the car a small puddle of antifreeze is sittin directly under the overflow. I changed the cap that's right next to the overflow as well as changed the thermostat. Pls help me as I have no idea whats going on with my car.

Jeff5808

iTrader: (7)

When the light comes on, is it low on coolant? or is it going off when it is full?
If it comes on when its full, it could be a broken sensor, a dirty sensor, a bad connection, or air. Try flushing your coolant and cleaning the sensor.
My 3rd gen did it a few times when I first got it.

Good luck,
Jeff

Aaron Cake

iTrader: (1)

There may be a pinhole leak in the hose from the pressure cap to the overflow reservoir container.

Neilanrx7

The overflow tank is filled almost to the top of the container. Way past the full line. The level of the tank never changes even when running

porsche4786

My car won't take fluid out of the overflow tank when it needs it either, but it does dump fluid in there sometimes, and I have to fill the radiator with more fluid. I didn't notice any bad hoses or anything. The coolant has been replaced several times when I had water pump problems.

trblsmeFC

doesnt there have to be some air in overflow/resevoir for it to be pulled out to the radiator.

craig3x

It might simply be a bad radiator cap. The caps are spring loaded and when the spring weakens, it allows coolant to exit the cooling system at a lower pressure/temp. This could cause your reservoir to fill up, and your actual cooling system to deplete.

Also, make sure there are plenty of neighborhood cats around to lap up your coolant puddles. They love that stuff! haha

ericgrau

iTrader: (1)

^ You joking or you hate cats? Sorry, hard to tell.

I would guess air bubbles if the buzzer is going on and off. Try closing all caps, squeezing a hose 50 times, and add more coolant. Repeat until you can't add more coolant. This method is a pain though and doesn't quite get everything; in the future I'd get a Lisle funnel (google it).

Fill the reservoir only to "full". Perhaps lower if you've just added coolant through a radiator cap. When coolant heats up it expands and fills the reservoir. If you fill it too high then the excess will overflow.

While you're fooling around with the cooling system make sure you use only an OEM thermostat (e.g., from a Mazda dealer) and make sure it's rotated so the little hole in it is on top when you put it in.

Aaron Cake

iTrader: (1)

Make sure the pressure cap works.

Make sure there is not a pinhole leak in the hose. It is classic for a car with a pinhole leak to fill the bottle but be unable to suck it back in.