BlazeF

OMFG! This is driving me insane!!! I don't know what is causing my car to overheat so bad! I checked the thermostat and the radiator cap... the radiator itself is fairly new... but it keeps overheating and doesn't take anything from the overflow...

I am probably going to change the thermostat and run some cleaner through the system... but guys... this is driving me up the wall...

oh... a note... when I was driving my car, I would see the heat rise... but if I hit a high RPM... it would drop down sometimes... like there was a clog or SOMETHING... dunno... please help

88 SE

Replace your radiator cap and thermostat. It's relativly easy and gives you peace of mind.

Kai

I had a minor overheat problem about a month ago. I could smell the coolant leaking and burning off, and the coolant went "bye-bye" to the point where I actually heard the ungodly low-coolant buzzer (upon start-up, not while running!) My solution: replace lost coolant, and replace both radiator caps. Done. When you see your water temp drop at high RPMs, it's probably because you are going faster and more cool air is passing through your radiator. Check everywhere for leaks in your coolant system, that's probably the issue.

Juan

iTrader: (28)

Remove the radiator cap when the car is cold. Turn it on and let it warm up. Rev the engine and if you see water shoot out of there, your coolant seals are bad. This means REBUILD time

Does the car smoke at all?? Do you have the radiator fan shroud on? Does your overflow tank get full?

silverrotor

iTrader: (1)

Are you running an electric fan on your set up?

Zaxfire

Also a reminder..Don't buy a Thermostat or a radiator cap from a parts store..Go to the Mazda Dealer and Order an OEM part..The Parts store thermo's aren't near as good as oem and they have different temp settings..I bought the parts store thermo and damn near fried my engine it ran to hot..I went to the Mazda Dealership and bought the OEM parts and Walla..It fixed everything...Just a tip..

SureShot

This really sounds like a worn out fan clutch.
The fan clutch uses a silicon oil viscous fluid in two chambers inside.
The Bi-metal strip bends outward as it warms and opens the valve from the reservoir side to the clutch side.
Centripetal force provides the pumping action to move the fluid.
After 80-100,000 miles the bearing seals wear, and the bearing lube weakens the clutch fluid’s grip.
The s4 clutch increases it’s bite gradually with temperature rise.
The s5 clutch is more on-off. (It just coasts until is gets warm)

Once they are warm, the fan speed goes up with engine speed to about 4000 RPM.
As the engine revs higher the fan stays at ~4K.
If your warmed up fan only revs up to ~2500 RPM, it’s bad.

CrazyDude

I would say it sounds more like a coolant seal failure. My motor did the exact same thing... temperature would shoot up rapily (on the gauge) and act kinda wacky like that.
Leave the car sit for a day or so and see if there is any white smoke when you start it. Also, do the test that wan suggested. Another tell-tale sign of coolant seal failure is bubbles coming out of the coolant return hose into the overflow tank.

The good news is that if this is what is actually happening, your motor isnt really overheating! This happened a few times to my car and when I took the engine apart, the rotor housings were not the sickly brown color on the bottom, which is what you expect to see on a signifigantly overheated motor.
Try some of that Bar's Stop Leak or maybe some Block Weld (special procedure required, do a search on the forum!!).
StopLeak actually supressed the problem in my engine for a couple months.

OC_

you know, if you change your coolent every now and then, the system lasts so much longer...

BlazeF

OC: I add coolant in my car almost every friggin week... I've had this car for 2 months now... previous owner took *** care of it...

everyone else: I will change out all that stuff, "cap, thermostat" but I also am hearing a small leak from the thermostat housing... I used one of those "create-a-gastket" dealies... and its leaking... so I think when I change out my thermostat I should put in a gasket there as well... :/ I hate this problem so much...

also... the fan clutch... yes this is also a problem... but it wasn't overheating this bad when I first got it... so these things will be changed first then I will replace the fan clutch when I get more money...

BTW I do have pretty bad exaust when I first start my car... white smoke... what is this from???

CrazyDude

BlazeF, that white smoke is coolant burning. If you let the motor sit for a couple of days, enough coolant will leak into the combustion chamber to flood it... with coolant! and that can make it VERY hard to start.

You'll also notice that when it "overheats", if you shut it down, and then start it up again in 1-2 minutes, there will be a LOT of white smoke.... this is because there is a hole from the cooling system into the combustion chamber somewhere. When the motor isnt running, coolant leaks in. When the motor is running, exhaust gas is pushed into the coolant.
If you tear your motor apart, you'll be able to tell instantly where the coolant seal let got... its not too uncommmon for the wall of the casting of the iron housing to actually have given way.

Unfortunately, your motor is hosed. Fortunately, it probably didnt suffer overheating damage. If you are going to pull your motor apart youself, check the color of the rotor housings on the bottom.... if they are brown, then bolt it all abck together and send it to mazda for a reman and make all that warped crap not your problem!

If you are going to rebuild your motor yourself, give the folks at Revolution Rotary a call; they are very helpful and can supply you with good used iron housings (and new rotor housing at a good price). Take them by Mazdatrix (your in SoCal right?), get them lapped, you'll be "right as rain". And buy the Atkins Rotary rebuild video. You can rebuild you engine; I'm only 17 and I did mine over the summer.