Ive been searching the forums to help fix this issue for the last couple of months and nothing has been working so i am making my own

i bought a 1986 RX7 GXL back in November and 2nd day i started driving it its had a overheating issue there was a coolant leak on the radiator and on the water pump housing i have replaced the water pump and gasket and replaced that gasket that is in between the water pump housing and block which stopped the leak. I have also replaced the thermostat with new gasket and put a Koyo Radiator in. i have replaced the pressure cap too I've replaced everything in the cooling system except the fan, the hoses, and the block itself. we did a block test on it (don't know how useful that is for a rotary) and everything seemed fine i don't have lots of white smoke coming from the exhaust only a little now and again if its humid out so i don't think the coolant seals are blown. my last speculation is the fan itself i know the clutch fan works i hear it turn on sometimes so unless that it isn't fully engaging i have no idea what the problem is i put coolant into the system and i bleed the system with a little plug that is on the top of the radiator near where the hose connects which is also on the stock radiator but the coolant for some reason is being pushed into the overflow tank and out of the tank with a hose coming off of it like it is stock i don't know why its doing it and i would very much appreciate it if anyone had any things to look for or any solutions

 

My first guess- and guess it would be- would be the clutch fan.
I hate those things, which must be admitted up front, but will concede that when new/working properly, they keep the car cool enough.
The clutch never fully engages nor disengages, perhaps it seems OK but is actually slipping under load.
Worth investigating.

Also worth noting that a goodly percent of your cooling comes from the oil system...have you looked into that?

You also appear to be having bleeding issues, which is fairly common.
Make sure your heater temp control is set to HIGH (so coolant flows through the core) and use a Lisle-type funnel.

 

First, when does it overheat? When you are driving, when you aren't moving, always?

Also, you mention that coolant is coming out of the overflow tank, if I read it right? The coolant should expand out of the block/radiator into the overflow tank, then get sucked back in when it cools off. Is it just going into the overflow tank and staying, then it keeps filling up until it spills out?

 

welcome to the board.

my first thoughts are:

1. what cap did you put on it? you can maybe start playing around with those.

2. have you actually checked the chambers for the presence of coolant or checked the coolant for the presence of combustion gases?

 

I too have chased the puking overflow issue for years (well not really years, just I only touch the car about once every few years!). To get a warm and fuzzy, do the "champagne test". You leave the filler cap off and start the car. If it bubbles like you just popped a bottle, then you've got internal seal issues. If not, it could be a number of stupid things like the radiator cap or a leak somewhere in the system. I'm still searching for that stupid thing, but it doesn't appear to be the engine.

Good luck.

 

I didn't get the bubbles until my coolant seal was REALLY bad, so that's not 100%. You can rent a coolant system pressure tester from auto parts stores to see where a leak is. Just as an FYI, the one I rented wouldn't fit correctly, so I had to improvise.

Also, I know OP mentioned the block tester. You have to follow the directions very carefully to get an accurate reading. I haven't used one on my RX7 (didn't know they existed until early this year), but on my Miata it took 2-3 tries before it correctly showed that the head gasket was blown (functionally the same as a bad coolant seal). I can't remember specifics, but you have to let it get up to full operating temperature to open the thermostat, then pull out some of the coolant so there is an air gap.

Also, if it only overheats when driving, even cruising, make sure that the lower radiator panel is in place. If it overheats when stationary but goes back down when you move, check the fan is working and the fan shroud is in place.