Just started the car, White smoke is back! Stops after car reaches operating temperature. Coolant is still OK but appears down from my last check of two days ago. Pulled oil stick and I can't see any moiture contamination. The smell of the smoke is almost definietly moisture.

But when I say White Smoke, I mean White Smoke and lots of it.

So let me recap!

The problem started about two weeks ago when the smoke first started. Started car one Sunday AM after sitting for about 2 days and the White Smoke came bellowing out. Prior to the smoke, I was getting a lot of AntiFreeze on the garage floor and coolant was going out at about 1 gallon per month. Found a leak in the Radiator, so replaced the Radiator. As well, replaced 4 injectors on passenger side due to miss at idle.

Idle corrected with injector replacement, but returned at start up to miss for about 30 seconds then it smoothed out. Miss is still there at start up.

Following this service is when I heard the loud Thwack sound emanating from front of car. Smoke returned shortly after the injector replacement and so replaced the Transmission shift sensor. Felt that ATF was being sucked back into the system causing smoke. Eliminated the Cam oiler which might have occurred at injector replacement. Seemed to subside and then it returned. Not all of the time but every once in awhile on start I would get a lot of White Smoke. Again at operating temp it stopped.

Took car back to shop. Seems that the cooling system had significant pressure so replaced thermostat.

Following all of this, car expereinced another thwack sound at start. Not as loud as before but the same sound. This time I didn't need to restart as car started simultaneously with the noise. Previous 2 times it took 2 starts to get it to go following the noise. When the key turned, car would give nothing except a slight Starter turn. Everything lit up and after 2 tries car started.

Today on initial start White Smoke returned. Again at Op Temp it went away.
On return from clearing the smoke, pressure is up again on the cooling system.

Can find no leaks under the hood, garage floor almost dry. Not even any Air Cond overflow.

I must have more than one problem. The mechanic I use has always been really good. Never threw parts at a problem always went thru step by step diagnostics. Still does. Wouldn't replace the Trans sensor until we proved that nothing else seemed awry. I know this is contrary to the previous but he is a sharp guy and I trust him. I just think he is a buffaloed as me. Problem is that it seldom smokes for him, and he hasn't experienced the Thwack noise. Naturally the car performs well after warm up and runs better than ever.

Sorry to keep posting but I'm really at a loss.

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1988 560SL
Black Pearl/Palamino