ok my brother's old radiator blew. he installed a new fludyne unit and we flushed the system and filled it with coolent and water. the car has overheated 6 times in the past two days!!!! his friend installed the koyo unit last night and today he overheated and in both cars the end result is a dump of most of the coolent. my brother took his car to a local mazda dealer and the service people did a number on his car. put two bottles of radiator stop in, drained the ac coolent, cut the boost line to the turbos and then when he brought it back the next day because it ran like ****, they told him that he blew his motor and that he had to sell the car to the dealer so he won't be burdened with the high cost of getting the engine rebuilt. after a bunch of bs they supossedly drained and filled the radiator with straight coolent and no stop stuff. well 6-8 months later his car still has a ton of that **** in his car. we rant the hose through it for 30 straight mins and it was still coming out. it looks like a thick rust mixed with a foul smelling substance. i ut some of the stuff in a zip lock bag that i was going throw at someone and i couldn't get me led flashlight to shine threw it!!!!!!! but enough history. the problem at hand now is how to keep his car and his friends from overheating and dumping the coolent. i think that the themostate is bad. could it be something else? could the new higher capacity radiators be causeing another problem? i was going to upgrade in a little while but now i'm not so sure. has anyone else had this problem? thanks.

 

huh?

 

Yes, it probably is something 'else.'

No, most people upgrade to a Koyo and have no problems (except maybe fitment issues, filling coolant to the 'max.')

 

my brother has the 93 touring model and i've got the r1 and our buddy has the base model. is this common???? it really is confusing me. i thought that the bigger radiator is supposed to help keep the engine cool. could a coolent sensor be bad? I bought a couple of thermostats to replace my brothers and to keep one on hand in case something comes up. what could cause this?????

 

Though the stock radiator has plastic tanks, it will usually not "blow" just because it got weak. The reason they "blow" is because the engine seals start to let some compression pressure from inside bypass into the cooling system like a bad head gasket on a piston engine. It starts off small and is hard to notice but grows over time. Eventually enough pressure resides in the coolant system and the weakest link lets go, the stock radiator.

Replacing it then doesnt fix the actual problem, if the problem was the engine to begin with.

Not saying that IS the case, but it is something to be considered. Anytime you have unexplained coolant loss and/or overheating and cannot seem to keep the system full, yet the components of the system appear to be in good condition, you suspect the internal seals.

Be sure your fans turn on between 205 and 215, be sure there is no blockage leading to teh radiator, be sure you have the plastic undertray, replace the thermostat with a mazda oem version, be sure your water pump isnt leaking at the weep hole under the pulley, and other than that, there's nothing special about the cooling system.

 

the local mazda dealer put two bottles of radiator stop in my brothers car when he took it in for just a drain and fill. i think that stuff may have gummed up the thermostat and god knows what else. the engine was rebuilt like 20000miles ago and it's always ran strong. i'll try to keep him from freaking out about a blown engine.

 

why in the hell did you go through all of this bs? you have mzm performance right there in austin, and Gotham Racing and Rotary Performance right up in dallas/fort worth. People that don't know how to work on their FDs should let professional shops do the work. In the process of trying to save 100 bucks it would appear that you have ruined a perfectly good FD. I hope that the motor is ok.

www.mzmperformance.com
www.GothamRacing.com
www.rx7.com

 

it looks like the thermo switch is bad and we're going to replace the t-stat as well. we noticed the fans weren't kickin on and as long as the car was moving the temps were good. we'll probebly replace the top caps for the ast again and the filler. my brother took out the overflow bottle and gave it a nice simple green bath and a tooth brush scrub to make sure there were't any cracks in it. he's draining and filling it to get any crap out of it untill we get the new switchs put in. needless to say we are VERY PISSED at the madza stealership that he took his car to. I curse at it everytime i pass it on my way to work. but i'm figurein the t-stat and the fc thermo switch mod should fix this problem. i've heard different ways to do the fc switch install, what's the best?