1988 Mazda RX7 NA Manual Transmission 25x,xxx miles, engine #2 according to the previous owner, a buddy of mine

Hey guys, long time no see! It's been about six months since I've driven my car due to it no longer starting:

I was getting onto the highway and traffic wasn't really letting up to let me into the lane, so I had to check several times to make sure I was clear not to hit anyone upon my exit lane as I speed up and make a spot for me. I glanced at the cars behind me once last time before I moved over, and by the time I looked back at my RPM to shift, I was in the red with the needle dancing...

Now, this didn't blow my engine, but over the next several weeks I did notice my coolant temperature gauge rising occasionally on normal drives. I checked my cooling system to discover that the radiator had I don't know how much coolant in it. So I promptly filled it back up, bled the air out, turned the heat on max, etc

A couple weeks later, the same thing happened, after filling my coolant system again however, the following mornings I noticed that my car would make clouds of white smoke (steam?) as it would warm up, then disappear after a minute or so. Also I noticed my exhaust was quiet momentarily (there's a recent exhaust leak at the closed end of the stock Y pipe. This car is stupid loud) and sort of cough or fart out the blockage and return to "normal" volume. No such problem was present during actually driving the car. It only seemed to do this after it had been sitting a while and the engine cooled.

Eventually, it started doing the same white smoke 100% of the time the car was on, so I decided not to take it out and catch the bus that day. Again, no leaks under the car. The engine no longer turns over (still cranks). I haven't looked into it much because money was tight, but I feel as though it's leaking internally... So, is it time for a rebuild?

 

If it's leaking internally, don't let it sit to long that way. Drain the rad and engine.

 

coolant pressure test from autozone or other rent-a-tool places?
if has internal leak and want to have engine rebuildable a not full of rust drain the coolant from the block including the drain plug on the block.

I had a FC with coolant leak issues, replaced hoses, pressure tested and found copper crush washer on turbo banjo bolt was leaking after 20 psi but fine under 15psi. anyhow fixed that and still had "bubbles in coolant system".
Replaced stock plastic capped radiator with koyo and now seems to be fine~200ish miles.
Put front of car up on jackstands to make radiator cap the highest point and jam/put a funnel that fits the coolant fill neck tight-fill and burp hoses multiple times then fill a little bit more and run car with heater on full.
sounds like you did the get bubbles out the system before.
rx8 buddy used alumiseal stuff and has had no issues for about 500miles at least AlumAseal® | Stop Leak Products for Radiator Repair like $7 i think
found thread
https://www.rx7club.com/1st-gen-arch...-maybe-750774/
seems like good results give it a try if on a budget, buy some time to save for a proper rebuild/replacement engine

 

Certainly sounds like you are burning coolant, white clouds pretty much confirm it with your other symptoms. If you let the engine sit with coolant in the chambers there wont be much left to rebuild.

 

Alright guys, many thanks for the tips! I've drained the engine and coolant several days ago. I'm down for a rebuild, although I wanted to get one last hurrah of natural aspiration before I reach that point of no return (turbo). I'll do some searching on the forums to see what all I can give this car for horsepower

 

Drain the coolant and put a couple squirts of oil in the spark plug holes. Turn it over a few times. This will preserve what should be a rebuildable core. Thank me later