well since i am sure that you didn't catch the problem as soon as it happened. you were probably driving it before with coolant in the oil. just check your fluids and make sure you have plenty of both of them. i don't think that another 20 miles would hurt it.
If it is in the winter make sure the radiator is full of water with antifreeze before starting the car. If this leak is not too severe it should be ok to drive a couple of miles to a mechanic.
You can drive it a little but make sure there is plenty of coolant. Don't let it overheat, not even a little. If it's leaking too fast, you might end up having trouble if you drive it, but you should be able to put in some coolant and drive it to a shop.
Where was the leak coming from? the coolant has some pathways that go to the intake. that's to warm up the air.the most important question is where the coolant was leaking from?
If it is leaking coolant. And you changed the thermostat. I would then move to this section. Flush the radiator and the heater core. This can be done at a certified shop with a reliable mechanic.
By the time the coolant has completely run out, the engine will have overheated enough to do serious damage. The heads will be warped and the engine may sieze. If the temperature light comes on, let the engine cool down before you do anything. If it is leaking badly, like a burst radiator hose, have it towed in. If it seems to be leaking slowly, you may be able to add water to drive it to the shop, but if it's winter, that's not a good idea.
Either a leaking intake manifold or a blown head gasket. You can take it to a repair shop and have a block test done. That will tell you if it is a head gasket. DO NOT drive anymore than needed as the water will destroy the engine bearings.
Have system pressure tested at local shop unless the problem is obvious. Check coolant lines (upper and lower) to see if they are leaking. Check radiator for leaks. Water pump may be leaking. Also head gasket could be letting coolant in to oil. Pressure testing will check all these components
Try to find out where it's coming from. Often coolant will leak down the front of the water pump, under the pulley. Even if you don't see the coolant, look for the mineral trace of the water. By the time you notice a leaky water pump it has usually been leaking for a while and has left a noticeable trail. If you don't notice coolant leaking there, check other places, freeze plugs, the sides of the radiator, radiator and heater hoses... Again, the coolant and water minerals typically leave a nice bright trace to tell you where it's leaking. If the radiator is leaking, don't try to fix it yourself and certainly don't put stop leak or any other chemicals in it. Either replace the radiator or take it to a radiator shop and have THEM repair it properly.
Seeing smoke from the tailpipe usually means your engine is leaking something thru a gasket. There are multiple gaskets as well that could be leaking. ou have to determine what fluid id leaking (coolant or oil (or both)). The color ofthe smoke helps tell what type of fluid is leaking. White - coolant / blue/black - oil. Coolant - usually leaks thru the intake gasket which is VERY VERY common on Alero's. They now have a better grade intake gasket available. I just replaced mine on my 99 (under warranty thankfully). It costs around $500. Oil - you could be burning oil from worn piston rings, crankshaft seal, gasket, cracked part or head gasket (where it mixes with coolant). To find out what is leaking - check the level of coolant in the reservoir and monitor the level over the course of a week or two. If it gets lower, you are leaking coolant. Same for oil. Get an oil change and then check the level every week to see if you are gradually getting lower. you can also have a shop do a compression test of the engine. Hope this helps.
what year make and model? it could be coolant or oil. take it back to the shop that fixed it and have them fix it. it is possible that smothing is loose or damaged. or it could also be a new problem.
Its Kinda` Hard To Do A Good Job At Home. If You Want To Get Serious With This Drive Over To A Radiator Shop. They Can Do It For You.
you can drive with radiator boiling but will do damage to engine if driven far better to let vehicle cool down, refill with coolant to get it to shop and have problem fixed or call a wrecker to tow it