Newbie coolant issue problem

[Chistopher]

I know very little about the radiator system in cars, but it would appear my car is leaking coolant. I noticed my heater wasn't heating my car so I checked the reservoir and the fluid level was at the bottom. I topped the car off, but the the engine wasn't 100% cool, however it had probably been sitting about an hour. Now about a week and 600 miles later it is back to the state of the heater only working when the car is moving.

Is this simply an issue of me not putting enough coolant in it because the car was still warm enough for the fluid to still be "expanded"? I want to check for leaks when I get home, but I don't know where to begin looking.

 

[86GT351]

Coolant system is a sealed pressurized system. If it is low again, there is most likely a leak. If you are not familiar self admittedly, I would suggest getting it professionally tested.

 

[Chistopher]

That's what the plan was most likely going to be, but seeing as I have a general engineering degree and a decent amount of handiwork skills, it would be neat to at least try and figure out and if it's something simple fix it myself.

Also I know there's such thing as fluids that fix leaks, but I'm betting that's not the play on a radiator system because it could clog up things up more than anything?

 

[86GT351]

That's what the plan was most likely going to be, but seeing as I have a general engineering degree and a decent amount of handiwork skills, it would be neat to at least try and figure out and if it's something simple fix it myself.

Also I know there's such thing as fluids that fix leaks, but I'm betting that's not the play on a radiator system because it could clog up things up more than anything?

To start, you would need a radiator pressure test kit.

 

[Dino Dino Bambino]

To start, you would need a radiator pressure test kit.

This.
If you pressurize the cooling system to 16psi (same as expansion reservoir cap rating), you should discover a leak if there is one. The commonest sites on the 4.0 V6 are any of the rubber hoses, the water pump, and the plastic thermostat housing.
As you top up the system with fresh coolant, leave the cap off the expansion reservoir when you start the engine and switch the heater onto the max setting to evacuate any air left in the system. After a minimum 10-minute drive to get the engine up to operating temp., let the engine cool down again for at least four hours and top up the expansion reservoir as required.