Jtrotor

My rx7 just started overheating and I have no idea why. It overheated, so I turned the car off and my radiator overflow bin was boiling water. So i let it cool off and checked the radiator and it was completely out of water. So i filled it up with water and it still overheated. Does anyone know what is wrong???

whereiscarmensandiego

possible block in the system,check your t stat it might be stuck closed.

but honestly in most instances it means that your coolant seals have gone bad and u need a full rebuild.

to check the coolant seals remove the rad cap and fill it to the tip top and turn the car on if u see a stream of bubbles then this is a bad sign,also u can see smoke from the exhaust and it will have a sweet smell

it boils because the hot exhaust gases are being allowed to mix into the coolant and super heating it

AWDRFTR

yes i have come to that problem aswell. i found that the my engine overheats alot, but i dont run out of coolant or water, im cheap so i have mostly water. i found that we all know our engine just run a lot hotter than the other cars with pistons in its class. i have asked around and i have gotten the same answer, the oem radiator ( espeacially the origional if still in the car) is just not efficient enough for the hot whether. i dont have a loss of fluid, nor do i have sweet smelling exhaust. my engine just gets HOTS, so i took the thermostat completely out to keep it open 24/7. i have been running it that way for about a month now, and nothing has gone wrong. when i first bought car, i took it to a mazda speacialty shop, their first recommendation is to upgrade cooling system.

whereiscarmensandiego

theres room for improvemnt but really its capable people run 400hp cars with the stock rad all the time.

and u shouldnt run without a thermostat your car runs hotter then if it was installed. even though it opens and allows coolant to flow at a given temp.it also provides somewhat of a blockage to allow the coolant to stay in the rad longer to allowing the coolant to become cooler.

without it the coolant is allowed to flow at maximum speed and the rad isint allowed to cool to its best potintial

and using plane water is bad as the chemicals and minerals in it are corrosive to the seals and block.if u really want to save money and pure water does cool better just buy acouple gallons at the supermarket thats pure there less then 1$ per gallon

TongassT

Check/replace your thermostat with a mazda unit and flush the system. Fill using 50/50 DI water and antifreeze. Don't just remove your thermostat, and don't run just water.

Zell

iTrader: (2)

Get your radiator flushed or replaced, mine use to over head after a bit of trashing once i got the radiator flushed it was all good, these cars are almost 20 years old theres alot of **** build up in the rads according to the guy who flush mine it was 80% blocked, factory thermo should be fine just keep the cooling system well maintained Mazda did do hot weather testing with these cars before they bought them out.

Jtrotor

I replaced the thermostat and flushed the radiator. It does not overheat now, but it still gets a lil bit hotter then before this happened.

V8what?!

summer time makes things hotter.

clokker

iTrader: (2)

No, really?

Your premise is faulty, your solution is FAIL and I'd look for another specialty shop to frequent.

If your car is running hot, something is wrong and you need to find out what it is and fix it.
Assuming it's not an internal engine issue...
-Pull the rad out of the car and see if the matrix is clogged with crap. Especially common if you have AC as the space between the radiator and the condenser is a ideal leaf/dust trap which can severely impede airflow.
This what mine looked like when removed...


-Make sure your fan clutch is functional, it may not be locking up when hot.

-All shrouds- bellypan and fan- should be in place and don't forget the foam that seals the radiator (which is probably deteriorated by now) to it's mounting support.

-Just go ahead and replace the thermostat and radiator cap- they're cheap and easy.

Less likely (but still possible) causes...
- Waterpump impellor is corroded- replace pump.
- Oil cooler thermostat not opening...higher oil temp leads to increased strain on the cooling system (this happened to me).
-Brakes dragging.
-Water hoses collapsing.

Since the OP didn't mention anything about the car's condition or previous maintenance, I'd recommend the "scorched earth" approach- replace the rad, waterpump, hoses, thermostat and rad cap, all in one fell swoop. It's an easy afternoon's labor, you only have to dump/replace the coolant once and you eliminate the most likely problem components at one time.
It's a lot cheaper and easier than rebuilding the engine after the coolant seals blow...

blwn rtr 89'

iTrader: (5)

if i where you,

i would
1-take motor out of car
2-take motor apart
3-clean diligently all coolant passages
4-purchace all new hoses, radiator, surge tank
5-rebuild
6-go to a BMW dealership
7-buy either G-05 or G-48 coolant......They contain neither silicates or phosphates
8- fill and replace t-stat

and btw if u do get the G-05 dilute it with distilled water.

aluminum engines... especially hot runners tend to dislike heavy partials in the discount murrys shelf brand, 2EHA works well also, the
PH level of G-05 is like 6.5, so you have to dilute it, the G-48 is a base so it all fine as is

ill spare you my maintaining procedures

wrankin

wow, doesn't anyone actually search anymore?

here's a hint, and it's been repeated too many times before: do not remove your thermostat - if you do, then much of your coolant never goes through the engine, but rather goes through the bypass channel that is normally blocked when the thermostat is installed (and warm).

-b

blwn rtr 89'

iTrader: (5)

assuming you are not an idiot, said scenario should not ever be a problem

ericgrau

iTrader: (1)

The thermostat is the first thing to check, especially after a sudden failure. Replace with Mazda OEM (e.g., from a dealer, www.rx7.com, www.mazdatrix.com, etc.). Auto store thermostats suck. While you're waiting for a new thermostat, going without a thermostat will be fine. It's just not ideal. Without a thermostat:
1. There will be nothing to block off the bypass. That means less coolant flow to the radiator for decreased cooling performance.
2. The ECU will go into open loop mode. That means you lose about 2 mpg.
3. Your car will warm up slower. That means you'll get increased engine wear if you drive hard while the car is still cold.

You can also use an auto store thermostat temporarily. Don't be suprised if it runs hot or fails quickly should you keep it too long.

If that fails try the other things people mentioned, or use the cooling system diagnostics guide at www.aaroncake.net.

Always refill the cooling system with a 50:50 antifreeze to water mixture. You need antifreeze to prevent boilover and rust. Distilled water is better than tap water, to prevent sediment buildup. 50:50 is a very rough ratio; if you add a little pure water or pure antifreeze it won't matter. In the future replace your coolant and thermostat every 12-18 months. Find a list of scheduled maintenance items for this and other important maintenance items. Try the owner's manual, a Haynes manual, the Factory Service Manual, etc.