ok hear goes. finished puting motor in on thursday drove car some friday and was realy going to put some miles on it today after about 30 miles the uper tank explodes the question is ,is this something that was just gona happen or do i have some major engine problem ?

 

Nothing your engine does should make the radiator blow apart. Even if it was running hot, your coolant system would just vent the extra pressure into the overflow tank. The plastic endtank on the radiator was probably just old and weak.

Now, if you ran the engine for a while with no coolant, you might have an engine problem. But its not what caused the radiator to fail.

 

I had the same thing happen on an '88 N/A. Ruined the engine, even though I shut it off and coasted for the shoulder the instant I saw a white puff come from under the hood.
If you look at the radiator in the '88s, the top is plastic crimped in place on the brass radiator body. What a crappy design. That design is so bad, it's a failure just waiting to happen - not a question of why; it was going to happen some time regardless of what you do.
Anyway, the '87 radiator is soldered brass throughout. I'd suggest a salvage replacement from '87, or - as I did - an aftermarket replacement (new) which is all metal.

- k -

 

Stock FC radiators suck, that's why it happened. ;P

Although it sounds fishy that you weren't pushing it or anything... something had to cause a higher pressure in your system for it to literally blow up, but if it just cracked I hear that's normal. Yay Mazda.

--Gary

 

My radiator also cracked at the top. I replaced it with a metal stock replacement radiator and went on my merry way.

 

Stock radiators do not suck. You can't complain about a 17 year old part failing.

There are two possible causes. One is the tank failed due to age (old plastic gets brittle), the other was that the radiator cap failed to regulate pressure as is should and excess pressure caused the tank to fail. Personally I'd replace the cap as well as the radiator.

And before you run out and buy an expensive aftermarket radiator, remember that the stock radiator lasted 17 years and new one will probably last just as long. The same radiator can keep modified Turbos cool, so unless you're racing or in a really hot climate, additional cooling capacity is not required.

 

thanks guys the car had been siting about 3 years and it did crack. any sugestions on were to get a good after market unit . these mississippi summers are murder on cooling systems anyway . thanks

 

Man, those are some damn good points!

James

 

Hi. I have a rx7 turbo 11, front intercooler with 550 cc injectors and with a walbro 255 lph fuelpump in tank and a fuelpressure regulator from rx7 jear 1993 (batman). My problem is wen I run for a while my turbo become so hot that it become red of color. The temp. of the motor is good. It's not running hot. What is the problem.

 

The heat coming out of your engine is over 1700F. And the turbo is just absorbing all of that heat.

It is normal.

Unless it happens just at idle...theny you could have issues.

James

 

Yeah sure, great point. That's why our Volvo's radiator is still perfectly fine.. '91, my dad's Acura's is fine, '91, my sister's Jetta, '87, my dad's old jetta, also '87... all never had radiator problems.

Whatever excuse.. they suck, even if you take care of them. Forget it if you want to run the car hard.

--Gary

 

Besides all that stuff above........Here is my theory.......based on what happened to mine. My situation is very similiar to yours.

Your old motor may have had seal problems that allowed the coolant to seep into the rotor housings when the pressure got too high. Now that you have a new block, the weak areas are surfacing.

 

well mazda's radiator is $551.30 is it realy $401.00 better than an aftermarket with brass tanks ?

 

^^No, the stock unit is inferior. You can get a very nice all-aluminum one for cheaper.

You mentioned that motor work had just been done to the car. In the course of working in the engine bay, it's very easy to lean on the upper radiator tank and damage the brittle old plastic.

 

thanks guys i cant justify spending 500+ for mazda rad thay must have lost there mind .
will have to go aftermarket this time .