Hello,

1985, 1.3 l , carbed, sons car. Last night he had the "add coolant light" come on. Engine getting hot. We took a quick look and there is proper coolant level.

Where do I start?

Thanks in advance.

Brett

 

Check the reservoir, make sure there is coolant in there. The low coolant light sensor is on top of the radiator. Make sure it is contacting coolant.

 

oo **** you have a gsl-se , love them ..... check resvoir ..... and give it a coolant flush and change the thermostat while your at it since you just recently bought this car ... correct?? so doing the basics wouldn't hurt

 

Check the wiring on the coolant level sensor (top of radiator as stated) and make sure its not corroded. Mine did the same thing, so I unscrewed it, fiddled with the wires, then put it back in. Hasn't done it since.

If its overheating, you may have another problem. If it only does it when the car is stationary, I would make sure the fan is engaging. Otherwise check out your thermostat.

 

Thanks guys...just figured it out and the car is fine. I bought this in the fall for my 21 year old son. Car had 107k miles but was in mint condition for upstate NY. Guy was waiting on delivery of a new Miata convertible and wanted to sell it to someone who was into RX-7's. He was asking $4500 and ended up selling to us for $2000. Through on new exhaust, plugs, wires, and it has been great. I have an 1980 RX-7 that I bought new and have babied since, no winters, 26k miles. My son has been floating on a cloud since.

Tried to talk him through the "add coolant" issue over the phone. He is just now learning anything about motors. He had capped off the reservoir per my instructions thinking it was the radiator ! When I told him to let the car cool down and check to be sure the radiator had enough coolant in it, he was checking the reservoir. I went out this morning, topped off the radiator and all is well.

I thought for sure I would find a bad water pump when I went our this morning and this was a much easier fix.

Thanks again, you guys sure are helpful! Saved my *** more than once!

 

All is not well.

You should not be low on coolant. Need to verify that you do not have any type of leaks such as a coolant hose, radiator, reservoir bottle cracked, radiator cap seal bad, etc... Still could be a water pump leaking. They do not always show up right away.

Make sure he is monitoring the level on a regular basis. If it goes down again then I recommend that you either go over the cooling system with a fine tooth comb or take it in a have the system pressure tested for leaks.

 

I agree with doc. If the coolant level is dropping, there's a cause for it. I chased one on my FC for a month until I found a tiny leak at the hose connection to the heater core. Turned out the heater core tube was out of round and not completely sealing. Another hard one to trace is a leak in the coolant recovery system, whether it be a pinhole in the rubber line between the radiator and coolant tank or a pinhole in the plastic dip tube in the coolant reservoir. When this happens, the reservoir often remains full, leading to the false assumption that it's working.

One of the most common failures is the heater hose coming off of the engine directly under the oil filter. Over time it gets oil soaked and deteriorates. Hose will swell and soften, often leading to a complete failure, rapid loss of coolant and terminal overheating. It's an expensive hose to replace, but much cheaper than a rebuild.

 

I agree with going over the cooling system, initally checking the connection for the sensor at the top of the radiator. If the hoses show any signs of deterioration replace them. I had a heater hose go on my first RX-7 and by the time I realized it went my temperature skyrocketed and destroyed the engine.

The most crucial part of these cars/engines is the cooling system, the couple hundred dollars for new OEM hoses sure beats putting a new motor in.

My personal experience is that the problem is usually the sensor connection on the top of the radiator. Just going overboard with warning you about cooling system maintenance...

 

i cleanded the connections and all is well. and i had some low coolant and toped it off. and i will also keep a look out for leaks. thanks for the tips.

 

Be very careful with that coolant level sensor and it's lead, too; the housing is plastic, and will happily break/strip if overtorqued even slightly; the lead is very exposed up on top the radiator and is easy to tear loose by accident.

The little plastic sensor is a $35 part that can take the car offline until you get one that doesn't leak.

 

hey so i still have a problem with my rx7 fb basicly the "add coolant" light is on and beeps and i cant get it to go off , got not leaks the sensors are new and it dosent seem to over heat

 

If it over heats, there is a reason. Bad water pump, bad t-stat, bad coolant seal.

Inspect the exhaust to see if it is sweat smelling/ If it is, bad coolant seal. If not, change the water pump, t-stat, and all three water pump gaskets.

UPDATE: Since it isn't overheating or loosing coolant, the sensor can be bad. Like said above, grounding the wire should make the buzzer stop, but it's an important sensor.

 

If it is not overheating, and the coolant level is not actually low. Just ground your sensor wire and the light will go away. Just routinely check your coolant level. And watch your temps.