i digested the comments to my previous post...

this morning i drove the car maybe 1 km and the car began to hit the mid-mark, threatening to creep higher. fearful of damage, i hit the park-and-ride which allowed me to consider what a new rad/water pump would cost...

after work, picking up the car, i decide to test the temp. behaviour. within the city streets, stop-and-go, comfortably sitting below half. i hit the highway with a vengeance and the temp creeps, but only just, JUST more than half. i slow down and the gage drops.

my thinking: there's coolant. the engine cools when it is running below 60 mph/100 km...start with changing fan belt. could it be slipping at higher revolutions, without a telltale shreiking sound? how about thermostat? i am leaning away from this as the gage does not bounce madly. still...

nonetheless tomorrow is another day to observe behaviour as i will be driving to work. i plan to change the belt anyways. plus it will give me a chance to get at the trailing tach so i can test it. as always $$$ is a factor. i sure do hope it is the belt...

norman ng

 

Slipping belt's a possibility. You could also have a blocked/corroded radiator core. It's worthwhile upgrading to a 3-row core if you get a new radiator.

I probably wouldn't bother changing the water pump unless it's leaking. But, if you do decide to change it make sure you get a OEM pump with the good cast impellar. The aftermarket ones have a crappy sheetmetal impellar that are more prone to cavitation at high rpm.

You might as well throw in a new thermostat as they're so cheap and easy to replace anyway.

 

Have you put a new radiator in yet? If not it's definitely time. All cars work the same whether rotary or piston when it comes to cooling. Rotaries just use less coolant because their overall combustion temerature is lower due to their high area to volume combustion chamber ratio combared to pistons.

All 8 of the cars I have owned have all needed radiators at 10 years. They just get plugged up from deposits. I don't use that flush stuff because it can eat up your gaskets and really makes things worse. The flush frees debris that really floats through the engine and settles more in the radiator vanes.

Spend
6 bucks thermostat
130 bucks radiator
and another 20 to replace those hoses while your at it.

Your water pump will always work if it's spinning. It's a centrifugal setup so almost no resistance to motion. So don't replace it unless it's leaking.

 

greetings,

appreciate all the comments.

nonetheless i believe i will begin attacking the problem by replacing/tightening the belt and replacing/testing hte currect thermo.

why? because i really tried to drive the car HARD today -continuous stop-and-go during the morning and i even tried to get a few car to "go with me" tonight -i push a max of 100 mph albeit not more than a minute...

nonetheless the gage never went above half way. this minor/major temp. issue is driving the **** side of me bonkers. i would like to drive my rex with a free spirit until the late fall/winter when i will begin saving for a new suspension. for newbies (even "newer" than me!!!): don't drive your rx7 while wearing a white shirt and drinking dark liquids!!!

originally i thought everything was belt related, but tonite i drove w/the heat at full blast and i did not reach the half way point. at idle, i began dropping below the mid-point quickly. i am now beginning to believe that the thermostat is to blame. anyways, i will begin slowly: start with the belt on sunday, and then whatthehell (it is a low cost fix...)get/order an oem thermostat from mazda monday.

i figure low $$$ fixes first. eventually i will get to the expensive stuff (as this car is a LONG TERM commitment -as oipposed to some relationships...). comments welcome!

regards,
norman ng