The mechanic who said to leave the rad cap off and watch for bubbles was on to something, even if he was an idiot.
Bubbles are an indication of a warped block in a rotary engine - a cracked block or head in a piston engine - that is letting water into the cumbustion chamber. If thats the case, you should see white-green smoke from the exhuast and smell antifreeze in the exhaust.
I'm leaning toward the blocked rad theory, but once a rotary is warped, its junk. Even overheating for a few minutes can do it.

 

Info so far on over heating engine:
- upper rad hose hard as steel when car has been running as opposed to it being very pliable when the engine is cold

- upper rad hose is supper hot (cant even touch for a few seconds.!) after idling for a while.

-when i shut off engine the clutch fan continues spinning a dozen or so times till it looses all momentun.

- between clutch fan and the engine is the hottest part of the engine bay?!?!?.

- i keept my overflow bottle empty purpously

- when it overheats by the overflow bottle.

- oil cooler gd shape

- rad missing alot of little fins and is a POS in general(but is not leaking)

- car running rich (till i get o2 sensor)

so those are my symptoms anybody else have these, we might have the same problem.

 

i overheated the **** out of my rotary and it still runs fine (I had no choice i was going up a bridge and my rad hose busted)

 

GSL-SE, there's no point in getting all worked-up about the engine failing internaly. The best approach to this problem would be to replace the parts you suspect are causing the problem one at a time. Start with the termostat. Take it off the car and hang it in a pot filled with water (make sure the thermostat doesnt touch the pot!). Slowly boil the water until it opens fully (~95ºC, 203ºF). If it doesnt open, then there's your problem. Make sure to put it back on with the spring side inside the water pump and the jiggle pin (or little hole) UP.

If that checks out, I'd go for the rad. Just go all out and replace it with a Mazda or an aftermarket RX7 rad. Yours is fried anyways right? You need to replace it one way or the other. You'll also have to replace that fan clutch, but dont worry about that too much... it helps cool things down, but a bad clutch should not cause an overheating problem.

If the thermostat works, and the rad is new, and you still have a problem, then you have a real PROBLEM. Hopefully one of the above parts will prove to be your problem.

 

Forgot something... the thermostat should start to open around 82ºC, 180ºF.

 

Making some progress, the old radiator looked much worse, once I got it out. Going to pick up a replacement radiator at lunch!

What have you figured out so far on yours Johnny_84_GSL?

 

It was pretty easy to get the radiator out!

Darn, I have a picture, but it's not showing up wierd! I'll try 1 more time.

 

Let me try it again!

Well nevermind!

 

O.K. Lets see.............

Mr. Moderator sir, can you clear out my failed attempts?

Thanks,

 

Another way to check for a bad water seal is to get in the car when its totally cold.

Squeeze the radiator hose to make sure there is no pressure.

Then get in the car and turn te engine over a few times.

Squeeze the hose again. If its pressurized already, combustion pressure is getting into your cooling system.

I don't think that is what is wrong with the POS Racer though, sounds like the radiator. Good thing you got a new one.

I'm not sure about GSL-SE's car though.

Pull the cap off and see if it does this:



"Note: The engine was NOT running, this was just cranking the motor over trying to get it to start. "

Hopefully it doesn't. I had a 13B that had a bad water seal, and it didn't mix oil and water. I have one outside that did though.

 

What's the worst thing that could happen if someone leaves just water in the cooling system?

The prior owner of my -SE sold the car to me with just water in the radiator. Clear as drinking water! I don't know how long he had it like that, but I'd like to know what I should be on the look out for in case corosion is creeping around my housings.

No over heating problems, thank ol' mighty!
It's August, and around 100 degrees some days.

Do you guys mixed distilled water with the Radiator fluid, and is the mix still 50/50?

Anyone use water wetter like Redline?

 

Antifreeze acts as a lubricant as well as a coolant in an engine. It can't possibly be good for an engine to run with only water.

 

Your symptoms sound exactly like what the POS Racer is/was doing!

Also take a peek at your fan belts, I had replaced the ones on the POS Racer just a couple weeks ago, but hadn’t inspected the tension on them since. While putting the new radiator in I noticed the Air Pump and Alternator belt we both a bit loose. I have a feeling this in combination with my trashed radiator may have been causing my problems. Didn’t quite finish the project tonight; hope to get it done tomorrow evening.

 

Rotary-MG,

Water will cool the motor better that the std. 50/50 antifreeze mix, but it has no lubrication for the water pump. It will not hurt the motor, but hte water pump my not live as long. All road racers run 100% water with some pump lubricant added (Redline water wetter is a lubricant and work great!) because the water will not cause a wreck if you blow a hose in a race (antifreeze is slick stuff). Just make sure you use distilled water.

later,
B

PS - anyone have a spare running 6-port 13B?