I realize this issue has been discussed so I am here to post a thread about the problem and how I fix it.. just as a general helping hand to those who may encounter the same problem.

The other day I noticed a substantial amount of coolant leaking from the front, driverside side of the engine bay. Upon further inspection I realized that it was nearly impossible to pinpoint the leak without some minor uninstallation .

The Problem:
The leak is inconsistent as far as how far I drive compared to the severity of the leak, so I've come to the conclusion that is depends on the time of day (ie how hot it is outside). It appears to only leak during the daylight when it's 100+ hear in Oklahoma. I figured if it were a hose or clamp , it'd leak more consistently and more often so I am assuming the issue is the thermostat? I'm guessing the the malfunctioning thermostat is telling the truck it's runing too hot and sending coolant when not necessary, thus causing the reserve resevoir to fill up and overflow, causing the "leak".

I picked up a new thermostat from NAPA for $8.56 today and am about to swap it out for the old one. We'll see how that goes.

Any Blazer querks I should know about? I'll wait a day or so and see if the leak stops and post the results!

 

If the overflow bottle is overflowing, then it could be a few different things.

The thermostat may not be opening up properly to allow the flow of coolant out of the engine block and into the radiator which can cause high temperature in the block, overheating the coolant, causing it to boil and push past the radiator cap into the overflow bottle. The temperature gauge inside the truck should show higher than normal engine temperatures if this is the case provided the coolant level inside the engine stays as a liquid and does not flash to steam.

Another problem could be a failing or weak radiator cap. If the system is not maintained at ~16psi, the boil point of the coolant in the system drops. This can allow the coolant to boil at a lower temperature, thereby increasing the pressure in the system pushing past the weak or defective cap into the overflow bottle.

I would replace the radiator cap first. I prefer the Stant Safety Cap. Cheap and robust! And couldn't be easier to replace so long as the engine is cool.

 

Well I went to my mom's friends house who has been certified master mechanic for the United States Post Office for 40 years now and upon his inspection, the radiator is cracked. He showed me the source of the leak and there are actually three cracks in the side of the CHEAP plastic endcaps. So we did not replace the thermostat, instead I'm going to NAPA to buy a new radiator and he is going to teach me how to put it in! It will be a learning experience for me plus free labor from him

 

I fixed the problem so I figured I'd update.. Turns out the radiator was cracked on the left side endcap. Took it to a local guy who replaced the part, flushed the radiator, lined the inside with some sort of chemical treatment, and repainted the entire thing all for $85! I ripped it out and put it in so there's no labor. Problem resolved!