PLEASE HELP: Overheating problems... radiator fans? cap?
 

So im breaking in my new engine and im having overheating problems..
not sure where to start or whats important to know so im gonna list everything that could be possibly related....

mods
half bridge ported engine- 250miles on build
greddy 2 row FMIC
custom intakes with greddy/trust filters
koyo radiator
peak 50/50 anti-freeze
radiator cap it the one with the spring.. it says 0.9 on it
AST delete

so i drove the first 20 miles trouble shooting...
the next 80 miles it was running on the hot side.. cruising at 2500-3000 rpms at about 80mph and water temps were at 103, peaking at 110ish?

took out the thermastat and tested it, perfect working condition... re burped the system from the coolant line behind the UIM.. (also messed with the idle pins, idk if that effects anything)

next 100 miles car drove pretty well, temps stayed at 93 in town...

now all of a sudden it over heats, this scenario happend twice... its reached up to 126 and i had to stop and pull over for it to cool down... then the coolant light came on.. so i cooled the car down and filled it with coolant.. ended up putting a gallon in BOTH times.. im checking around the car NO leaks, and if there is nothing enough to leak out a gallon TWICE in one day... no leaks, no mixture in the oil, no clue where its disapearing to..

now when this happens it smokes out of the resivior tank... keep in mind when i bought the car it did not have the resivoir neck or cap....

the known bad. i have dual fans for the radiator.. ONE of the fans isnt working, i have to flcik it before it starts spinning and it spins slowly... ive swtich the connectors and stil same outcome. so its deffinately the fan, not the wiring. but i dont believe that ALONE should be a change in water temps by 30 degrees?

this usually happens when i boost. i stay in vaccum 98% of the time... so im assuming when i boost the heat rises and the pressure builds pushing against the raditor cap spring allowing coolant to escape into the resivior tank and thats causing me to run out of coolant...

i know there are many variables to this but can anyone shed some light or suggestions or ideas that can help me diagnose this problem? my mechanics out til tomorrow so im trying to eliminate all possible problems as soon as i can...

also anyone know where i can buy new fans for my radiator? its a koyo rad.. bought the car modded so idk if its a stock fans or what not...

thanks in advance
-benny

i am having close to the same problem.

1. I would check and see if the belt is slipping. I am running a greddy underdrive pulley kit and had the air pump taken out. my belt slipped so bad that it has taken of the finish on my pulley kit. The belt never made noise either.

2. Next question is do you have an aftermarket engine management system. ie power fc, aem? If so what temp do you have the fans coming on? stock is around 200*F. I would set them to come on at a lower temp.

3. read this and see if it helps---------> https://www.rx7club.com/3rd-generation-specific-1993-2002-16/high-oil-coolant-temps-help-850671/

actually, matter of fact i do have greddy underdrive pullies as well and i did mess around with them while checking my thermastat... also the finish of the pulley that provides tension on the belt was already worn off when i first bought the car...but how does the belt slipping effect my water temps/loosing coolant?

i have the air pump delete and im running an apexi pfc, im pretty sure i have the cooling fan mod aswell so they both come on sooner? any way to check that??

come to think of it i do think my belts are loose... im a rookie at how things work and didnt realize how tight they should be... but doesnt explain the loss of coolant?

thanks for the tip, about to read that thread now..:icon_tup:

If the water pump belt is slipping then the water pump is not pumping water though the system. causing the water to heat up. I dont know if it will cause you to loose water but this happened to me. dont over tighten the belt

read this------------>https://www.rx7club.com/showthread.p...t=idler+pulley
then this---------->https://www.rx7club.com/group-buy-center-69/air-pump-deletion-idler-pulley-kit-807734/

thanks a lot! good reads... i think that is definately one of my problems a long with the undertray... but now im wondering why is my coolant disapearing?:dunno:

you said smoke is coming out of your reservoir... could that mean that coolant is boiling off through there.

You really should find out exactly what is coming out of there.

im positive its the engine coolant bubbling/steaming out of the resivoir.... how do i handle this? higher pressure rad cap?

When the car runs cooler the water is not going to boil off. I never got the car that hot. I hit 215 by the coolant fill (radiator cap) with my defi water gauge, and 108 on the power fc and lost coolant. I didnt loss that much coolant though (about a cup or two). What is your oil temp? do you know?

no oil temps or oil pressure... yeah.. bad i know...

im thinking the over heating is due to one of my rad fans not functioning and water pump pulley slipping (even tho i dont think i can tighten it anymore)

other issues...
Cap.. what psi rating should i be using? i have a 0.9 cap whihc i believe translates to 13psi...... should i be running a 16psi cap? where can i get one? autozone/pep boys ones good enough?

where can i get stock rad fans?

also what is the round black circular connector that connects to the water pump? its right under the green connector that sends water temps...

another things.. should my reservoir tank be filled up with coolant when cold?

ps... my friend told me if i check my plugs and they look clean that means its a coolant seal since they act like a steam cleaner... can anyone confirm this? i checked my plugs and there is definitely signs of carbon (i havent been boosting nor revving high due to breaking in the engine)

is your radiator mounted in the stock location, or is it upright like in an FMIC install?

its mounted up right like a FMIC install but i angled it slightly forward

Might be a mix of of your Front mount, stock bumper, and one running fan adding to the over heating.

Okay, so i ruled out its a coolant seal bc my plugs are covered in carbon (i believe im running rich since im on a basemap to break the engine in) if it was coolant seal the spark plugs should be clean and or have a white rings/spots on them...

Overheating problems.
1. DEF bc only one of my fans isnt activating.
2. the black circular connector broke that activates the fans at high speed.

now the only question/ mystery i have left is where is all my coolant going? my ONLY guess is my pressure cap isnt holding its seal?

i dont think your car is overheating due to the waterpump pulley in your scenario because the belt usually begins to slip at high rpms.

Make sure your caps are all good.
Fans are extremely important and you should really make sure there running at 100%
Run 70% water 30% coolant
If that fails try buying a new thermostat. mine seemed fine but when I replaced it my temps dropped. (you may even want to consider drilling a few holes in the t-stat)

well when i boost (going into higher rpms) my temps sky rocket so thats why i assume the belt is slipping...

i need to check my cap...
i need new fans..
i am running a 50/50 mix but ive add plenty of water..
thermastat is good, did the check and i BELIEVE its an oem one aswell

once again over heating isnt my concern as i have a few things that should cover it.. but can anyone shed some light on the disapearing coolant?

I'm having a similar problem with my FD overheating when it wants to. I have to replace coolant every morning due to the Boil-off from the overflow tank. I seems not to mater how hot the car gets or how much driving I do. I can cruse around for 1-2 hours and park the car and the coolant gets stupid hot (temps on the engine read normal) and bubbles out of the overflow and AST. However I drive 20 mins the next day and all my coolant all the sudden boils off and the car screams toward overheating! I don't know what is causing all this:dunno:...But in the case of the missing coolant, it's prob just evaporating off and boiling out as you drive so you don't notice it.

Failed coolant seals.Confirm by performing the so called "champane bubble "test.If you continue to run the motor you will render your rotor housings unusable due to warping,infact they may be scrap already.