MK
So I've had this project going on for a while now, only recently has it become drivable, but after some down time (school starting, moving, rugby...etc) things slowed down a bit, recently I just installed a new guage cluster- autometer tach, and mechanical equus triple all together where my old cluster was... get it cranked up, runs alright- think my starter is sticking slightly after the motor turns over- but go to drive it (sat at 164 for about ten minutes... ) and it starts to over heat, reached 160 fine, then it jumped to 180 mmmk, it got up to 205 and I cut it...any ideas??
I just installed a brand new radiator- oem replacement for the time being...
went to go check the thermostat after it cooled down- and there wasnt one???? or is it not in the upper radiator hose housing? obviously I missed this key ingredient on the replacement of old parts...but wouldnt that make it run cold instead of hot? any ideas? whats normal ot for a 12A? Any help is greatly appreciated!!

-zach

 

this is also after driving it an hour and a half up to school from atl- all on 75N without incident...

 

HHmmmm,,, when my old one started to creep like that. It was a water seal on the inside. Not saying that's your problem, just sounds similar. She isn't smoking white is she? Not even a little?

 

Nooo, lack of a thermostat will make it over heat. if your missing the thermostat then you need to pick one up. Also remember that these cars run hotter then piston cars. THough Im not sure what the over heat temp is.

 

https://www.rx7club.com/1st-generation-specific-1979-1985-18/water-pump-684416/

 

morey- no smoking at all, not even a little,
spyride- far out-will do before next drive, but im well aware that the rotary runs hotter...
doc- thanks as always- are you suggesting that it might be my water pump? is there an easy way to see if my impeller came off without removing the housing?
**also of note- I have a fair amount of rust in the coolant, not flakes or chips but rather its rust colored on the inside of my new hoses...

 

Sorry, not water pump. I thought you might of read all the way thru where I informed the member that it was not his problem.

T-stat needs to be in the engine especially in warmer weather. Without the T-stat to regulate the coolant flow, it will not stay in the radiator long enough to cool down. Which means that you are just picking more and more heat up from the load of the engine without allowing it to drop the temp. When you idle and there isn't the same amount of ram air coming thru the radiator the temp can rise dramatically.

It is a given that you need to install a T-stat. That's not the end of the checking.
You need to verify that the fan clutch is doing it's job. With the engine at operating temp there should be a fair amount of resistance when you turn the fan(Engine not running of course). If the fan generally free wheels then the fan clutch is bad.

Since you have stated that you see rust in the cooling system it needs to be serviced also.
Action plan;
Drain system. Get flush for radiator. Flush system thouroughly.
Install T-stat.
Bring engine up to operating temp and shut off.
Test operation of fan clutch as posted above.
As a precaution also, I recommend to pick up a new radiator cap.
Report back.

 

sweet- most definitely will do, picked up a new t-stat already, flushed out the radiator, drained the system, will flush thoroughly tom through block, will grab a new radiator cap, by fair amount of resistance what do you mean? (i know its hard to define with differences in force applied etc...) but should it be hard to turn? or should it just not spin after i lightly spin it by hand? will definitely report back tom pm....
thanks a whole bunch Doc! - do you see rugby injuries? ha

 

I completely agree with rxdoc. Solid plan!

 

by resistance i would say close to turning a tight bolt with slight rust. It shouldn't spin like a pin-wheel when you try and turn it.

 

try warming it up with the radiator cap off, check for coolant flow, there should be significant turbulent flow.

Also when the temperature gage is showing over heating sprinkle just a few water droplets on the block. If it is overheating , then they will sizzle. If not, then your temperature gage is giving you a false temperature.

Good luck

 

If the water pump and tstat don't change things check the oil lines if you have a FMOC. If they are very old replacing them may help your temperature problem. It did for me.

 

I don't know where you got this idea, but coolant temperature wise, they do not run hotter, nor are they supposed to. Yes, they can produce more heat, particularly through the exhaust, but coolant temps should run around 180*.

 

so, this project of mine has been roughly coming along for a while now, and today my motor took the dump of its life. i drove down to atlanta from school yesterday and then back today, car ran fine all the way up today right at about 175-180F, but this afternoon when i went to start it, it made a *HUGE* cloud of white smoke upon cranking, and smelled like coolant, but cleared up within a minute or two and ran fine. so i get up to school (its like 1.5-2hour drive) and turn the car off at my buddies dorm. go to start it up to drive back to my place and it wont crank, pop start it and it spews a fair amount of coolant out the exhaust, along with heaps of smoke. drive it back to the house again at normal temp, but yea- this means my motors fried right? at least my soft seals, or maybe the car sat at the previous owners place for too long and the coolant ate through the aluminium? either way teardown is in order correct? ive got a sp 12A ready to go in, was just going to wait a while til fall break when i could devote a week to it, but obviously my motor thought otherwise....thoughts, comments, snyde remarks?

zach

ps- anyone have a cherry picker i could make use of in east tenn (around cleveland area?)

 

Fall is in 6 days, so close enough i guess. get started and enjoy your new motor. keep a careful eye on this one. that would be the snyde remark, evgeryone else, be helpful.