A little smoke ...

[Brixius]

Hey guys,

I was the guy who had the airlock in the cooling system of his 1986 SE Fiero. I took the cap off of the radiator overflow and saw that after a while gas bubbled out and out of the container ... I think it solved the knocking noise it caused.

However, my question is that my Fiero seems to smoke after driving it a while -- not a whole lot, but it seems like it is running hot (my temp gauge's needle has fallen off). Could this smoking have been caused by the airlock in the cooling system? I haven't driven it since I tried to fix the airlock ... in addition, my radiator overflow seemed to empty every week or so.

Thanks,
Mike

[Ragtop_Renegade]

If the smoke smells "sweet and sticky", you could have antifreeze leaking onto hot engine parts. Otherwise, yes, air trapped in the cooling system will cause overheating. To release the air from the system, run the engine with the waterneck (t-stat housing, it's on the engine, the cap looks just like a radiator cap) pressure cap off, the overflow tank doesn't do the job. Don't keep the cap off too long, though, or it can boil over. As the air burps out, add fresh water/antifreeze mix, as air escapes you need to replace the space with coolant.

[Mines69Olds]

You could also have a head gasket leak. The coolant could be dripping into the combustion chamber causing a little white smoke. It would also cause your coolant to be low and your car overheating.

[Brixius]

"To release the air from the system, run the engine with the waterneck (t-stat housing, it's on the engine, the cap looks just like a radiator cap) pressure cap off, the overflow tank doesn't do the job. Don't keep the cap off too long, though, or it can boil over. As the air burps out, add fresh water/antifreeze mix, as air escapes you need to replace the space with coolant."

Do I add the antifreeze mix into the t-stat housing? Will it be obvious when the air burps out?

Thanks,
Mike

[MrPbody]

Yes, add coolant there. Also, try jacking the rear of the car up as high as you can safely get it, with the cap off. Sometimes, this can aid the air bubble in finding its way out. While running (at idle), pour in coolant there.

Jim

[Ragtop_Renegade]

Yes, that's what I meant. Jacking the car up is indeed a good idea, but if it's not easily doable for you parking the car on an incline with the nose pointed downhill (chock the wheels!!!!!) is helpfull too. Is the white smoke comming from the exhaust tips or the engine bay? White sweet smelling smoke comming from the tailpipe(s) would in fact be a head gasket leak, and can cause catastrophic cylinder damage if not addressed RIGHT AWAY. A little antifreeze will burn off ok, but a small gasket leak will at some point become a large one, dumping quart after quart of coolant into the affected cylinder(s). Coolant make a terrible lubricant for piston rings. The effect is not unlike pouring a handfull of sand into the spark plug hole and starting the engine. A leaking head gasket would also explain how air got into your cooling system in the first place... Just as coolant is drawn into the affected cylinder by the vacuum of the intake stroke, the compression stroke pushes fuel and air into the cooling system. Check for the scent of gasoline in the coolant, a telltale sign of a bad gasket. Fuel contaminated coolant also appears a nasty brownish greenish color, but this isn't a reliable sign as old dirty anifreeze is also a nasty brownish-green. Furthermore, that temp gauge needs to be repaired. Without it, it's impossible to know if you are damaging the engine by running it hot. Temp gauges can also show air is trapped in the cooling system - the needle will bounce between normal and redline as air bubbles move past the thermistor sending unit.