So first off i have roughly 1250 miles on my Rotary Resurrection rebuild in a 88T2. And a couple times I've had problems with it getting real hot. I drove the car for over 100miles last night and encountered no such problems, but today when i went to go to blockbuster the gauge was half way up and the coolant was boiling after about 10 minutes.

I tried to turn the heat on and at first luke warm air was coming out, then when i felt a surge of hot air i noticed the gauge falling. I just recently replaced the thermostat and radiator cap so I don't believe it to be either one of them. Also last night I was putting some boost to it and not experiencing it getting warm at all, but today I had been easy on it, I was also not seeing any clouds of white smoke.

 

Properly bleed the cooling system.

Also, see http://www.aaroncake.net/rx-7/cooling.htm

 

Did you put the CORRECT radiator cap on it...... there are links about this you have to use the factory style cap or things will go nutty on ya!!!!

 

Ok so this seems to be only an intermittant problem. I bled the system per service book recommendations. (bleed screw at top of rad.) I drove it all sunday without it even threatening to go above 1/4.
Then yesterday I go to drive it to school and 5 minutes later the temps are sky high and the coolant is boiling. When this happened there was no warm air blowing out again. Today i take it for a spin and the same thing happens, but at one point i did start getting hot air and the temps went down.
I think i hear a SMALL air leak towards the thermostat housing or the top fill cap. So i'll try and hit that with some gasket sealer tomorrow.

 

have you replaced the thermostat?

 

yes. not sure if it's OEM or not. So going to order an OEM one tomorrow unless someone recommends something else and it works.

 

I presume you got a new water pump on the rebuild...If Kevin put a new t-stat on it I'm sure he would have used an OEM one...I'm with Aaron- make sure it's bled properly...how's the radiator?

 

oem only

 

The radiator looks good. I thought i remember reading something that some lines might be blocked if thecar doesn't blow any hot air.?.?

 

yeh, the heater core, maybe, if the coolant system maintenance wasn't kept up...

 

How do we check the Heater core?

 

Based on the syptoms, I think it's pretty likely something is blocking coolant flow through your entire engine, not just the heater core. You noticed that when the heater started blowing hot air, the coolant temps dropped. It's very likely that coolant started flowing again at that point, since just the addition of cooling via your heater core would not be enough to go from boiling coolant to running at 1/4 gauge.

I think your best bet is checking/replacing the thermostat. Even if it is a fairly new Mazda thermostat, that doesn't mean it's impossible for it to fail. If you have a spare thermostat, cut out the center of it and install it in place of your current one.

 

well last night i followed ReTed's flushing link. Last night running just the prestone clean out stuff, and water it didn't go past 1/2 way. Then i filled it up w/ regular coolant today and it has run fine so far.

 

what is the danger zone for temps on a TII?
I've had mine rise up as far as half and I didnt worry TOO much about it, now its sitting down at 1/4 and hasnt risen up above that since.
I've also felt the temp of the rad and it seems quite hot, is that normal?

 

sorry its not really hot, just warm. I figured the rad should be cool at all times