scottguitarzz2002

K im gonna rack everyones brain to get some more ideas how to fix this....

I replaced the motor, and then just got a new radiator, also replaced the thermometer, the temp gauge isnt working for some reason? but i can watch the water temp on my power fc...

basically it heats up to about 60 c just from normal warming up... then after a few minutes, it shoots up really fast to like 70 then 80 then stablizes around 90-95 for a minute or so, then it starts going up again... if it hits 100c i turn it off and let it cool down...

ive tried the burping method, i even replaced the thermostat again... i even completely flushed out the radiator, got all of the coolant out of the ast and even emptied the over flow tank....

im stuck and dont have any idea what could cause it to not cool down... ANY IDEAS?

Rocking Rotary

iTrader: (14)

Hows the water pump? Do you have a diffrent IC? The only thing I could offer you since I cant see the car is (if its stock) make sure all the pastic ducts are there and the fans are turning on.

scottguitarzz2002

I dont really know how the water pump is or even a way to check it.... it worked fine before my motor blew... its still the stock IC and i dont have the air duct for it, but I should be getting a front mount in about 2 weeks...

scottguitarzz2002

oh and the fans turn on but not until i hit like 100 c or so... Im getting my ecu tuned for them to kick on early and getting a basic map loaded to componsate for the street port... i really need to get this cooling system worked out so i can actually drive it and break it in... its only got about 150 miles on the new motor

Rocking Rotary

iTrader: (14)

I would hold off on the front mount till you get your cooling issue done. Enless you like putting engines in your car.

Front mounts decrease your cooling efficantcy by 1/3 so your cooling system is going to be working double time.

I would deffently say that you need the ducts on before you go anyfurther. Also see if there is any gap between the sides of the radiator and the body if there is block them. One other thing to replace while your at it is your coolant caps. Sounds dumb but they do have a purpose.

Thats just my .02 and I hope you get your issue resolved.

scottguitarzz2002

Yeah i replaced both of the radiator caps... The new radiator i got is a little bit bigger and doesnt quite fit right... What would a gap between the radiator and the body of the car even do?

IRPerformance

iTrader: (41)

100C is not that hot. The car will hit that easily while sitting. When it approaches 120 I worry.

Rocking Rotary

iTrader: (14)

Directs air around the radiator instead of threw it. Becouse its the path of least resistence.

scottguitarzz2002

makes sense... what would u recommend using to block the sides? and out of coureosity what is like the normal temp it should run at?

ArcWelder

You may be trying to troubleshoot a problem that you don't have. A car that is just sitting while running will continue to heat until you get air flow through the radiator. The fans don't even turn on until 100degC. This is the temp that Mazda engineers found to be acceptable, so it's nothing to worry about. You can make the fans come on at 94degC by turning on your parking lights or turning your interior fans to position 3.

scottguitarzz2002

Im actually gonna tune my power fc to have the fans kick on earlier... But the car heats up a whole lot faster while driving... I think it just needs a burp... Now Ive heard several different ways... Tell me which is the best.... turn car on for 5 minutes then shut it off and immediately remove the radiator cap on the filler... not the ast... or warm the car up... let it cool down.. then remove cap... basically does anyone have the best over all recommended way to do this?

a3dcadman

iTrader: (1)

I have a thread currently running that deals with a similar problem to yours as well as a few other issues.

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/troubleshooting-problems-new-rebuild-537034/

When I was trying to run my brand new engine, I wound up shutting it down at 230F and didnt get to run it more than a few minutes at a time. I put a very large high output fan underneath the radiator (car was up on jack stands). In addition to that, I have the mod that allows me to turn my cooling fans on with a switch. This is really handy in hot weather when youre stuck in traffic. Despite running all the fans full blast and checking and doing everything possible to rectify my cooling issues as well as reading just about every post that pertained to this problem, my temps went to the max on my aftermarket temp gauge. The other problem I had was that my stock temp gauge for some reason was not working.

Got the problems solved and I put 300 miles on it this last week.

Another thing you can do to burp the system is to loosen the hose clamp holding the cooling hose going into the top rear of the throttle body and let it bleed out a little coolant and any air that may have pocketed back there. Do this shortly after starting the car. Dont wait till the car get too hot, if it blows off youll get scalded. I have a pair of special long handled pliers that grab around the hose and allow me to gently twist the hose and still control it while purging the system.

Are you sure there are no obstructions anywhere in your system?

Are you running excessively retarded timing?

Are your devices for registering your temps working properly?

What ratio of coolant to water are you using?

To check my coolant temps I jammed a large funnel in the fill hole on top of the thermo housing. I let the car run until I saw the level coming up in the funnel. I shut the engine down and then took a kitchen cooking thermometer and checked the temp. At the same time I also took the aftermarket temp sending unit and placed it in the coolant with a grounding wire attached and checked the gauge. Kitchen thermo read 190 and gauge read 260. Stock gauge which was not reading was fixed with a new sending unit. New aftermarket gauge and sending unit coming.

chuck

FLA94FD

100C in Utah sound about normal with the stock setup. I would hit 106C in traffic and 103C on the highway with all the OEM stuff.

scottguitarzz2002

what would anyone recommend using to block the sides by the radiator?

ArcWelder

Now that's a different symptom than described above.

A couple of notes;

You'll have a more of a problem in Salt Lake City because of it's altitude of 4000+ feet. Lower air density, less capacity for cooling.

When changing the thermostat, make sure the jiggle pin is towards the 12 o'clock position to allow trapped air to pass.

For burping from a first fill, I remove the coolant hose on the throttle body, fill until coolant comes out, then jack up the rear of the car and fill again until coolant comes out. Reattach hose, top off overflow tank, run car in garage until thermostat opens, let car cool completely and refill at thermostat housing and overflow tank. That should get you pretty close assuming that you don't have a pressure leak in the coolant system.

To close off the radiator it's of course necessary to run the undertray. To close off the sides I use some high temp spongy foam and stuff it in the gaps.

scotty305

iTrader: (2)

From the 3rd Gen FAQ located at https://www.rx7club.com/3rd-generation-specific-1993-2002-16/faq-3rd-gen-other-useful-links-68640/
,

Coolant Burping Tool/ Radiator Cap Funnel
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/radiator-cap-funnel-eliminate-air-bubbles-342309/


I recommend this tool. After filling slowly and burping carefully, the Lisle funnel removed a LOT of air from my cooling system. Also, I recommend running a 70/30 water/glycol mix for coolant.

-s-