So getting my 7 back up and running after about 7 years :/ . everything going okay, slow but okay. i am running parallel turbo setup, custom saldana radiator closed system, no AST, no reservoir. Just installed brand new OEM thermostat, using bleeder funnel i cannot get the thermostat to open. I will be trying a couple more ideas to get thermostat to open and water level drop to add more h2o. Going to try jacking front of car up tomorrow and bleeding, heard try and fill coolant line from rear housing to throttle body, been told "just remove thermostat" lol. , and finally heard mention of my heater core possibly being bad. My Power FC reading and holding @ 82C degrees. Gauge needle on cluster sitting right in middle and staying there . HEater Core is what kind of worries me, i search everywhere online an no one selling, no mention anywhere it seems. Any thoughts, ideas, experiences are appreciated. Just need to get this probem resolved so i can move onto next problem

 

at what temp should the stock thermostat open? i cant remember. maby its not hot enough yet
eh just saw you said holding @ 82deg..hmmm

 

82 Celsius, incase you didnt catch that, which converts to 179.6 F.
Stock Rx7 Thermostat supposed to open @ 176 F im pretty sure.

 

but are you sure the t stat is functional? put it in a pot of water and turn it on high with a thermometer and watch if it opens...

 

Yup, done it, it works.

 

I find with my car if I just leave it idling it will sit at 82 forever and ever. If I want the thermostat to open without driving I need to hold the rpms up for a bit to make the temp rise and get the coolant flowing.

-Geoff

 

When you fill your coolant to full, and then it heats up, where is the expanded coolant supposed to go? You say you have a closed system with no overflow. Why?

 

Thanks Geoff ill try that.

Adam- if I'm not getting heat in the car the thermostat isn't opening i need the coolant to go through the system, if it was going through system i wouldn't have the issue. As far as my system setup not having ast or reservoir i have seen guys do it before, it is a custom saldana dual pass radiator without cap or nipple to direct overflow anywhere anyways.

 

Update ....tried jacking front of car up and bleeding which did not help. Today temp holding but holding @ 84°C. :-( fan wired temporary constantly on.

 

Coolant expands when heated. It has to go somewhere. If it isn't allowed to go anywhere pressure will build, and it will blow something apart.

If your coolant temp is staying at 82, then coolant is flowing, and your t-stat is opening.

My heater doesn't work because the airmix door doesn't function.

 

Keep your foot on the gas at about 3k rpms until the temps rise some more

-Geoff

 

Adam - a little bit of heat is coming out the vents just very minimal. And if the thermostat is opening it would regulate a lower temp than 84°C.

Geoff- kind of weary holding at 3k for too long the motor has literally zero miles on it and approx. 15minutes collectively of run time. Think it will be okay?

 

^ Try just driving around the block maybe?

 

Yeah guess i could try Geoff's idea then that. Maybe this evening or tomorrow. Thanks

 

My car cane without a thermostat installed but I didnt like the idea of not having one so I put one in. I noticed that the car in general ran cooler. I attribute this to the radiator not getting so heak soaked. With the thermostat out the coolant always runs through the radiator evently making it inefficient, when I put the thermostat back in once the thermostat opened the temps would drop and it maintained my temps better. My temp with a thermostat were lower and more consistent. I would run the thermostat for those two reasons.

 

^100% agree.

So i got temps up to 83°C and held rpms between 2500-3000. Now here is a curve ball.....cabin heat got warmer like i hoped for but bleeder funnel didn't drop water level....meaning thermostat still hasn't opened. So now I'm lost. Unless its some grand canyon sized air pocket

 

If your t-stat doesn't open, the car will overheat .............. period!! If your car is staying at 83 for several minutes, the t-stat is opening.

 

did you drain all the coolant out of the engine block also or only the radiator?
if only the radiator your probably full and all good.
drive it and see what happens..just watch your temp which im sure as hell you would be!

 

Just rebuilt engine so no fluid was in engine

 

water level shouldn't drop in funnel. it actually goes up as the car gets warmer since water expands as it gets hot, that's why the cars come with the coolant expansion tank.


and like they said if the thermostat wasn't opening your car will overheat, since the coolant inside the motor will have no where to go.

 

Let the car run until it gets to 83 for a couple of minutes. Feel the radiator hose. It will get warm. That means the t-stat is opening.

 

Yes upper hose gets very hot. But feels empty

 

Cooling systems on cars are engineered to run at maximum pressures. When the system exceeds the maximum pressure, a release valve (normally a pressure cap) releases the pressurized coolant into an overflow tank. When the pressure goes down, the coolant is sucked back in. If there is no release valve, the system will over pressurize. Coolant will be forced to escape wherever it can. It will blow up hoses, hose clamps or whatever it takes to relieve the pressure. Worst case, the pressure will blow thru the coolant seals in your engine. This will mean rebuilding your engine. You cannot run a closed cooling system.

 

Guys on here have ran closed systems. There is even a wrote up stating that only 1993 fd thermostat hosing and neck can do it because its a different design. I understand the logic completely, but even if i decided to reverse this setup how would i even go about it? I don't have and way to relieve pressure from Radiator only inlet and outlet on radiator.

 

To go back, just get a 2 piece water neck housing and an AST delete kit from Ray @ Malloy Mazda.