My daily driver V70R finally died and I've been driving my 1990 rx7 for a few months now.

A short while ago I let the car sit for about a three weeks while I was out of the country. When I got back, I had to crank it for a long time to get it to start. It finally started and has been running fine since.

This past weekend I washed the car and topped up the oil. When I cranked the car up (about 8 hours after driving it the night before), the car was hard to start. It ran rough and I got lots of white smoke mixed with a little bit of blue. Once all the smoke was gone the car felt fine (plenty of power, engine sounds smooth when it revs). I drove around for a bit, but I discovered that if the car was off for more than 5-10 minutes, I got tons of smoke again (all white -- the blue is completely gone).

I've been driving the car for a few days and the quantity of white smoke has been decreasing. There is very little smoke emitted when cranking the engine. However, the engine is very choppy for about 20 seconds when it cranks, then after that it's fine.

I don't know if the exhaust smells sweet (hard to crank the car and stick my nose in the exhaust at the same time -- need to get a friend to help). The amount of coolant in the reservoir has not been significantly decreasing.

I searched the forums for "white smoke" and got lots of results. Apparently there are many different causes?

One post suggested taking the radiator cap off and starting the car cold. I did this and saw no bubbles.

What's the next step for diagnosing the problem?

Is the car safe to drive in this condition or am I likely to damage the engine if I am burning coolant?

Thanks,

Paul

 

white is coolant, blue is oil.

if your engine is burning coolant, it doesnt matter if you're driving it or not, its "already" damaged and requires a rebuild.

 

So coolant (antifreeze plus water) entering the combustion chamber won't further damage the rotors or rotor housing beyond the point of being rebuildable?

Also if I am burning coolant then why do I not see a decrease in the reservoir? How much coolant does it take to produce that much smoke? And why did I see so much smoke the first time it happened but not so much now?