I started having a slight coolant leak @ 58,000 miles . It wasn't until around 79,000 miles that it got really bad . the intake manifold gaskets are made of plastic and the dex-cool anti-freeze corroded them, Replaced gaskets with metal gaskets that have a rubber seal to prevent it from happening again and also now using universal antifreeze instead of dex-cool, Gm should be ashamed . Dex -cool antifreeze corrodes the plastic and GM probably knows this. Of course they want their parts to go bad so we have to buy more of them, I learned this from taking the car to 3 different mechanics and they all said same thing. The highest estimate to fix the car was 850 dollars the lowest was 532.dollars.Of course this included oil change and and flush the system out and replace with the universal antifreeze.

Had work done yesterday and not a drop of anti-freeze anywhere,,,I will say i LOVE my car. I take care of it . Check fluids regularly, have had minimal problems until this, but when this one dies, i WILL NOT buy another GM vehicle. Everyone says to Buy American, Help the economy. More people would if the American Manufacturers would stand behind their products. Compare a toyota or honda warranty to an American manufacturer;s warranty . NO CONTEST!

There is an elbow-shaped plastic piece attached to the manifold located in the upper area of the engine. This piece cracked (dont know exactly how or why) and shot out coolant all over my engine. I believe this happened as soon as I started my car up this morning because I noticed coolant all over my driveway, not to mention I went out the previous night and the car was running fine.

I found the leak by putting water in my radiator (not the coolant tank) and simply looking for the area where the water came out. I did this with the engine off.

I just need to know the name of the part (elbow-shaped piece) so I can buy it and fix it myself. I never get mechanical work done at a dealship. Any helpful comments would be greatly appreciated.

Update from Aug 26, 2011: Solution:

The "elbow pieces" are heater hose fittings to distribute the coolant throughout parts of the engine. Many other vehicles use robber hoses with clamps but not the monte carlo. The pieces simply slide in the slots securely, as long as there is no debris in there. the two fittings can be purchased in one package for maybe 5 dollars. The pain part is disaassembling the main belt, the tentioners and some others parts to make access to the fittings easier.

I have had a coolant leak problem but was not significant. I forgot to check the coolant level for a coupe of weeks. Suddenly, I had the engine light came on. I took it to the shop and they pulled code P0128. They found coolant leak at intake manifold gasket. They advised to fix the coolant leak and go from there. They also recommend replacing intake manifold gasket and thermosdat. I have decided to ignore the problem and watch the coolant level. The labor is more than $800 although the pieces are not too much expensive. They also advised to sue GM for call back :))