For the past two days my car has been overheating. There were no leaks anywhere and i had a flush about 3 months ago. My thermostat and radiator cap were fine too. So i decided to change my water pump. After i changed it , i drove it around and it still overheated. I opened the hood and the usual smoke was blowin from the radiator cap. The weirdest thing is my radiator is pretty cold. Shouldn't it been hot? what is goin on ?

Please any help will be appreciated.

 

when you changed water pump, how did the old one look? did the blades look OK? was it leaking from weep hole or around gasket?

you need to make sure the fluid level is ok and remove all air from system. look in manual or search forum to find directions if you dont know how.

and yes the rad. and upper hose should be hot. make sure thermostat is opening when it warms up. when engine is hot and then you turn it off, is it hard to turn the big fan?

 

if your rad is cold then change your thermostat.

buy a "mazda" one from a dealer. not one from a local parts store.

 

I second that!

 

i concur

 

What about a rad cap, mazda or whatever the local store has?

 

Is the entire rad cool, or just parts. If the heat is uneven, then your rad is blocked of gunked up somewhere.

 

I think for a rad cap, anything is alright, but don't get a piece of **** as doesn't it need to be able to hold a certain amount of pressure (or am I thinking of something else)?

 

Yep, I just removed a Victoria British thermostat on my S4 T2 engine. Noticed that it didn't have the little jiggle pin. I presume that is important to allow the air to bleed from the system.

I wouldn't take any chances with the thermostat--get an OEM one for like $19.

 

Hot engine + cold radiator = bad thermostat..

By the way, do not run without any stat.
There is a bypass hole in the housing about 1" below the stat seat.
The Mazda stat has an extra spring loaded disc to cover that hole.
If you ever have to run without a stat, block that hole.

 

I have found this out.... EVERYTIME I decide to cheap out on a RX-7 part..... it is the WRONG IDEA... The rotor gods are ever watchful and will smite you down with serious ferver should you put that autozone radiator cap on the car!!! Actually, some aftermarket caps can plug up the overflow hole and now allow the expansion tank to work right.

PS... if you get this fixed, and find that you car is hard to start after its been run hard... Welcome to the "I'm a dumbass and thought that that little overheating problem really didn't do anything to my coolant seals" club.