3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.

93 JDM RX7 Heating Issue

Old 01-28-19, 08:28 PM
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93 JDM RX7 Heating Issue

I just replaced the radiator and AST. Drove the car around for awhile and it was fine until one day it started over heating.

It was low on coolant due to 1 of the new hoses not having a good clamp. Filled it back up but now..
it over heats everytime I drive it. ( I dont drive it far enough to overheat a ton so im not worried about motor) but I can let the car idle for 20+ min and its fine tho.

I noticed the fans were not going off when it started over heating when I took it around the block. Besides a posible new coolant fan switch is there anything else I should look at?

Overall replaced.
Radiator, 2x hoses, AST, new thermostat

Last edited by Justin.K; 01-28-19 at 08:33 PM.
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Old 01-28-19, 08:42 PM
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Make sure all the air is bled out. The method I use was one of the lisle funnels, filled with front of car in the air and throttle body coolant hose off. Once thats done, start it and let it warm up until tstat opens and then fans come on. I let it idle for quite some time.

Do you have an aftermarket gauge or ECU to read exact temperatures? The factory gauge has a huge range before it moves and not something i'd rely on.



My fans will come on idling but never while cruising.. And they're set at 90 C

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Old 01-29-19, 05:18 PM
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Everything has been burped several times. Starting from the front as the front was jacked up.
I just got done ripping everything out and from the ast to overflow has a plastic nipple connector that was kinda crusty inside so its cleared out now. Got a coolant temp switch on its way just because.
Fans are off the radiator, no broken wires, all the relays looked fine but ill switch them around and see what comes of it once the parts come in.

The rest of the hoses seem to have been fine.

There is no aftermarket gauges or ecu or any of the sorts.
Its nearly 100% stock with the exception of DP, Radiator, Exhaust and suspension.
I reground the entire car several months ago and it ran better after I did that.
Ill keep the thread updated once the parts arrive and I mess around with her a bit this weekend.
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Old 01-29-19, 06:46 PM
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If you bled it with the lisle then you're good. It helps if you let it idle and unplug the fans as soon as they come on. Let it idle for a few minutes after that and then shut it off and let it sit overnight. All with the heater on of course. The system will be as bled as it ever will be. In stock form, bleeding the system can be a little tricky. There's a lot of hoses and pathways that air can get stuck.
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Old 01-29-19, 10:25 PM
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Ill give it another shot, maybe I just had air somewhere in it still.
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Old 01-31-19, 01:06 PM
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Make sure your fans are running as designed.
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Old 02-02-19, 01:20 PM
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Seems like none of the fans are running at all.
Took it for a 45min drive and then it started to get hot. Sounds like the water is boiling but I think its because the fans arent kicking on at all. I pulled over and they werent on.

Im not very electrically incline, is there a way I can run wires from the cooling fans to the batter just to see if they run? I tried looking but like I said electric is not my thing and couldn't find something I could understand.
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Old 02-03-19, 09:09 AM
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Just a quick update.

I havnt been able to test much of anything but I did notice my passenger floor is soaked ( left side, car is JDM ) .

I did have the heat running when I had the car going, So this tells me the heater core is shot and leaked all into the cabin which would explain why I smell coolant in the car at times.

Does this mean since the air is entering the system, that the air is getting hotter causing the coolant to sound like its boiling but not kicking in the fans?
Might be taking it to a person who works on them in my area as I dont have the tools to do a majority of the work anymore.
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Old 02-03-19, 10:20 AM
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Read up on it, there is a test connector for checking the fans. If it's running that hot with no fans you need to stop driving the car until you sort the problem out.

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Old 02-03-19, 12:09 PM
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Originally Posted by Justin.K View Post
Just a quick update.

I havnt been able to test much of anything but I did notice my passenger floor is soaked ( left side, car is JDM ) .

I did have the heat running when I had the car going, So this tells me the heater core is shot and leaked all into the cabin which would explain why I smell coolant in the car at times.

Does this mean since the air is entering the system, that the air is getting hotter causing the coolant to sound like its boiling but not kicking in the fans?
Might be taking it to a person who works on them in my area as I dont have the tools to do a majority of the work anymore.
you are correct. A coolant leak will introduce air into the system gradually which will ultimately cause overheating. Luckily the heater core can be bypassed very easily in the mean time without consequence. You can cap off the heater in and out on the motor and try again. If you follow the lines from the heater core, you'll see what needs capped. Use SILICONE caps and not rubber. The rubber ones will 100% fail and then you loose everything
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Old 02-03-19, 01:18 PM
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Thanks, will try that either later today or tomorrow. Still in th process of shop vac-ing the damn floor
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