We think we finally found where our coolant leak is coming from- but I couldn't tell you where, because I don't know what the part is called.

We have a 2001 Blazer with a coolant leak so bad that we have to put a half gallon of coolant in every day. It's ridiculous (this just started a couple weeks ago).

We thought the reservoir was cracked, so we've only been filling the radiator directly... and obviously, it's not the reservoir. The part nestled in behind the reservoir, above the passengerside wheel well, is where the leak is. We're thinking maybe a seal or a gasket...? Does anyone have any idea?

The coolant is being burned and pushed through the fan into the cab of the vehicle, as well- and if the AC is turned off, the cab is filled with the smoke/fumes. We don't have a ton of money, so we're trying to find out about what part this is, get an estimate of what it will cost, etc. without having to bring it in. If we have to, obviously, we have to.

Oh- also, it looks as if while driving down the gravel road we lived on the last 2 months, there was some damage to the wheel well. It looks like it was rusted already- so maybe there was a slow leak that caused the rust, or the damage caused a tear or something to cause the leak? I don't know. Help?

Sorry if this is all over the place, I really have no clue about this part of an engine

 

You need coolant in the reservoir for the system to work properly. You can remove the reservoir and fill it with water to test its integrity. It is fairly easy to remove. The point of the reservoir is to handle the overflow of coolant from the system as it warms up and expands. When the system cools, it pulls coolant back in to make up for the coolant pushed out when it was hot. If there is no coolant in the reservoir, it can cause the system to pull air back in, making the problem worse.

Air in the system has caused many people to pull their hair out. It can make you think that there are larger problems than there really are. I am not saying that is what is definitely going on here, but there are steps that should be taken as a first run at this type of problem.

I would drain the cooling system down. Replace the thermostat and radiator cap (Stant Safety cap is my preference). Fill the radiator and reservoir back up to their proper levels. With the front of the truck elevated as high as you safely can and with the passenger side being slightly higher than the driver side, run the engine up to operating temperature with the radiator cap off. Periodically blip the throttle and monitor the fluid level. Then allow it to cool and repeat the process until you see no visible air bubbles coming out of the radiator. Do this at least twice and then put the radiator cap back on and take it for a drive. When you return, make sure that the radiator is full and that the reservoir is at the hot mark. Then allow your truck to cool off.