So once again my car is trying to overheat at idle, I have a new radiator (koyo), new water pump, new thermostat, and the fans work fine. So my question is what else could it be because its starting to **** me off so any help would be grealy appreciated??? Thank You

 

do u have any leaks?? What are your temps? Have any more info?

 

You need to give us a little more info that that.....exact behavior during warm-up, what temps the fans come on, etc.

 

do u have a under engine tray?

 

just a thought! you may have air in the cooling system after the radiator install. burp the system and check further.
Jeff

 

Temps get up to about 110 c. I do have the bottom trays on. I dont have any leaks, I changed the upper radiator line when i did the radiator. I believe the fans kicking on about 95 i think that is good yes or no? I have tried to bleed air out a couple of times now, so I don.t think there is air in there but i realize the air pockets could cause it to heat up? Is there a way to make for sure that the air pockets are all out? Oh yes and when I let it warm up it seems to do fine its not untill after i start going somewhere and then get stuck in traffic that it will start to heat up and sometimes it goes a little over 110? I really appreciate the help cuz this is drivin me crazy.....

 

Stock AST ?
What are you running 50/50 coolant / distilled water ?
What type of temp gauge do you have and is the sensor mounted high on the filler neck ? It could just be trapped air like they mentioned above.

If you can live without the ac , that ac condensor covers up 3/4 of most aftermarket rads. I pulled my AC car never gets over 87c. I also wired the fans to a switch so I turn the on manualy and leave them on when I drive.

But best advice be patient, once you get all the bugs worked out these cars kick some ***.

 

Yeah ido have stock ast wich i should problably chabge for the metal one, i am running 50/50 distilled, i haven't wired the fans like you but i think i might try that this weekend. I have the greddy temp gauge and yes its mounted on the filler neck.
Yes I love this car and if i can get this cooling prob fixed man it would be great cuz this is one of the last bugs i have to work out cuz other then this it runs great....

 

You said you've replaced the thermostat, was the replacement OEM or a parts store aftermarket one?

 

did you block the air so it doesn't move around the sides of the radiator?

 

Keep in mind, with AC off, fans should rarely come on, and in traffic should have no problem keeping temps below 100C if fans are on at 95C, even with condensor on.

Make sure stock 82C 3-way t-stat was used, and have system pressure tested warm, with tee in ast line. Replace any old oem ast asap.

 

Undertray is very important, but won't make a difference at idle. Sounds like you have a coolant flow problem or air in the system. Did you use an oem thermostat and install it with the jiggle pin at the 12 o'clock position? Hoses to the ast or bypass if done and overflow hooked up correctly?

 

he said the car is overheating at idle...so:

stock or metal AST have nothing to do with the problem, same for AC, and undertray.

I am in Dallas Texas, in 98*F abient temperature/103*F heat index, with AC on, in 5 PM rush hour traffic temp never go past 95*C that is with stock AST, stock radiator. So 100*C at idle is definitely wrong.

Do a pressure check and bubble test.

 

Sounds like you still have air in the system. Bleeding the air out is a bitch.

Do yourself a favor and buy the $20 tool in this link https://www.rx7club.com/showthread.p...ighlight=lisle

Using that tool you can be sure that all the air gets bled out.

I also once had a situation where I had some fancy upper radiator hose that managed to suck air back into the system when it was running. It never looked like it was leaking but I heard it once sucking air in and saw some very small bubbles. I installed a stock hose with stock C-clamps and bled using the Lisle tool and all was right in the world.

 

The thermostat i did get from mazda so should be right one, at least it matched the number on the one i took out.. From what everyone saying it seems to be leading back to having air in system still, so i am gonna order that tool you linked me and try that, oh and the upper hose i replaced is still an oem hose i got it from mazda as well, thank you guys i will try that tool when i get it and hopefully it will work, i will let you guys know either way Thank you

 

A trick I use when filling the system is leaving off the coolant hose that goes to the back of the throttle body and squeazing the radiator hoses to help get the air out. When coolant starts flowing out of the throttle body hose the system is nearly full. I also use that funnel described above. Put the throttle body hose back on and run the car with the funnel. When the thermostat opens and fans come on coolant will get sucked it and you will need to add more. Keep the car running untill it takes no more coolant, then carefully remove the funnel and put the cap on. If it starts to boil over before the thermostat opens you have alot of air still in the system. Use the plug that comes with the funnel and shut the car off. Let it sit for a few minutes and patially remove the plug to let the air bleed. Be careful not to burn yourself. Start again.

 

Here is the current link...

http://www.lislecorp.com/tool_detail.cfm?detail=230

 

Cool Thank you....................

 

I have a KOYO and a FMIC and my temps never go over 90 deg in traffic ! Is it throwing out all the coolant through the overflow bottle ?, Last time I saw something like that it was a failed coolant O ring . To check this u can heat up the motor , then allow it to sit overnight and cool back down , next day remove the EGI fuse (so that the ECU is disabled) , the plugs and crank it over , look and see if any water is coming out of the plug holes , by the way , to help get all the air out of the system , just keep squeezing the lower radiator hose , you'll see the boubles coming out of the filler neck.

 

Do you have the stock intake box? If so, it's very likely that the thick Koyo radiator is sandwiching the upper radiator hose against the airbox. Try unbolting the airbox (leave the hoses connected, but unbolt it from the chassis of the car) and running the car to see if it still overheats.


IMHO, 50/50 is not a good coolant mix unless you live somewhere very cold. The coolant should contain 70-90% water, with just enough antifreeze to guard against freezing.


-s-

 

I can't remember what the FD thermostat looks like, but could you install it backwards? With the engine side on rad side? I've seen that done and will cause problems.

But it sound more like a thermostat then anything else. It's gotta be restricing the coolant flow. I'd pull the thermostat and put it in boiling water to make sure it's opening all the way. Just because it's new doesn't imply it's not defective. Maybe try the old thermostat?

 

I am running 50/50 right now cuz it gets cold here during the winter, and also i am not running stock air box it is completly removed i have two pipes and k&n cone filters.Also it has never over flowed any coolant at least not yet but i want to get it fixed before it has a chance to anything like that..

 

I like this idea i will try it after i get that kit i order and bleed the system so more which i hope works but if not i will try this Thankyou..

 

I am having similar issues. I have tried so many things I am starting to pull hair! I passed a leak down test and a vapor (compression leak) test.. Both you should do just to eliminate a oring failure! My next test is to check the over flow line and tank to make sure coolant is able to be pulled back in. I am hoping this is my problem as I only over heat when the thermo doesnt open during warm up due to air in the system. I am hoping it is from the coolant warming up pushing coolant out as it expands then during cooldown it is not pulling it back in causing excesive air in the system??? I will post my results..

 

man uguys suck.the rx-7 has brought us together like a family.so lets use our knowledge and experience with these cars and help eachother out im about to blow mine up.i jus need a little advice thats all. if not for me then do for the rotary.maybe we have the same problem