First off...

-79 RX7 117k original miles.
-2gdfis, BUR7EQP leading, BR8 12a plugs on trailing, almost brand new NGK wires.
-79 style Sterling Nikki, OMP, RB intake/foam filter.
-Unknown heat wrapped header, RB full exhaust.
-Emissions completely removed.

The problem have had with the car ever since I have owned it is on a cold start it has a steamy smokey haze coming out of the exhaust until the car has been driven a few hundred feet or it has idled in the driveway for a few minutes. The car performs quite well as far as power and gets roughly 20-23 MPG. I have noticed that the coolant level goes down a tad every couple months.

The smoke smells like a mixture of sweet coolant, oil, and gasoline. It will make your eyes water for sure. The car sometimes has a little hiccup on a cold start, but always starts up easily. It usually spits out a little backfire
after it has been driven for awhile.

Now I'm wondering if this is in fact a coolant seal starting to deteriorate? I don't think it leaks from anywhere else. I have blocked off the O rings on the intake manifold so it shouldn't be leaking from there. BTW the coolant is perfectly clear and bright green so no oil or gasoline is mixing in I take it. Does not appear to be any water in the oil either, unless my oil pan vent line is sucking it all out.

Should I try the Alumaseal trick?

 

I would guess that it's oil seal o rings going bad. This is the weakness of early 12a's that have sat for any amount of time. If the smoke is not too bad after driving for a few minutes, keep going. I ran my engine for close to 90,000 miles that way.

Do you lose any coolant? If it's a coolant leak, you'll be filling up the radiator every day or two.

RXDad

 

Often on a good running engine this is something one learns to live with. Most common source for start up coolant smoke are bad intake o-rings and/or very humid/cool nights. Since you have your's blocked off, it may not hurt to check that they aren't leaking. This is more likely since the coolant is clean. If it is a coolant seal, exhaust gases could be forced into the cooling system, giving the coolant a dirty look. Simple way to test for that is take it to a shop that can test for hydrocarbons in the coolant. Last possibility is residual pressure in the cooling system forcing coolant into the housings after shut down. If that's the case, a cooling system sealant may help.

 

Well, I don't doubt that the alumaseal would stop the seepage. The question is whether or not this is an issue worth resolving at all. That would probably depend on how fast you lose coolant. Since the alumaseal uses aluminum flakes rather than copper, I don't see how it could really hurt anything.