You have ascertained this hopefully by finding coolant on the ground under the car? Or do you have a mystery leak, where you need to add coolant but have no idea where it's going (check your oil dipstick). The heater core hoses run back to the rear of the block - follow them back out from the firewall and check there. Pretty much a PIA to get to from the top of the car. Normally it would be fairly easy to see any coolant leak, as the phosphorescent green will show up, or pressure test the system. You can make a homemade tester (suitable for leaks) using an old radiator cap, rubber insert and a schrader valve, then pump it with a tire pump.
'91 Tracker 8V, 1.6L, 5 sp, 4wd, 2dr, conv, CAMI, horribly rusty
'97 Suzuki Vitara 8v, 1.6L 5 sp, 4wd, 2dr, tintop, horribly purple
'61 NSU Quickly - 150mpg
Last edited by Bex; 10-22-2012 at 04:52 AM.