1999 kia sephia leaking antifreeze

Hi there.
Well you can either have a problem with either radiator outer {dust/dirt in outer core of radiator or clogged up inside were water goes, or soft hoses,blowen head gasket plus a few others ,but first go to garage to were you blow up your tyres and use the air hose and blow out the radiator core where the air goes in, 2 drain out radiator water and then refill with water at 1 ltr at a time and then check your info car book and find how much water the radiator takes ,if it dosent take all the ltrs then the radiator is blocked inside.
if engine runs rough missing etc then get your Head gasket checked out.
When you say no heat is that with heat on gauge or no heat from heater, as it could be heater blockage same as radiator core. So let me know how you get on.

The hoses could seem ok but have tiny cracks in them that you can't see if they were not replaced. With antifreeze the flange the hose goes on could be rusting from antifreeze and cutting the hose. Cut the end of the hose past the clamp mark if there is enough slack. and put back on. The clamp could either be too tight and cutting the hose on the metal flange or not tight enough. Squeeze the hose and if you see cracking in the hose replace it. Also, if you over fill it it could be a problem or you got a bad radiator. If it is a tiny leak in the radiator you can use radiator stop leak. http://picsbox.biz/key/radiator%20leak%20sealant. Check all the hoses and clamps and make sure the belt on the water pump is ok too. Good luck. They are a great car and worth the effort especially if you havea V6.

hose or metal pipe is rusted they can go. but could be the water pump on some models.

sorry to tell you but you have a blown headgasket or cracked cylinder head. that is why the coolant blows out of the radiator and the engine won't start due to engine compression getting into the cooling system.

If you have the V6 (2.5L) engine, be advised: it's a wearing task. Just getting to the radiator drain plug can be a problem without a 3/8 inch drive ratchet, a 3 inch extension, a universal joint. and a 19 mm socket. The drain plug is on the passenger side of the radiator on the engine side. The 19mm socket will fit over the drain plug to turn it open.
The coolant plumbing on this engine is the craziest I have ever seen. The thermostat is on the rear face of the engine (where the radiator hoses connect), but not on the upper hose where it connects to the upright pipe with the radiator cap on it, it is on the lower hose connection. Pull that hose off the housing, and remove the three bolts holding the thermostat housing to the engine. It will help if you first remove the big air inlet hose from the air filter housing to the throttle body. I wouldn't even bother with the thermostat till you have found the leak. Is any coolant leaking from the front of the engine, dripping off the bottom behind the crank pulley? That would be a water pump problem or SEAL, an o-ring on the back of the water pump. Now get on the driver's side and look around on the rear of engine nearest the firewall where engine and transaxle mate. Look down there for signs of coolant coming from rear of engine and running down onto the transaxle case. There is a metal pipe laying in the valley below the lower intake manifold, connecting the water pump at the front and the rear housing where the radiator hoses and heater hoses connect. This metal pipe uses an o-ring for a seal into the water pump, and the same size o-ring to connect to the rear housing. If one of those o-rings is leaking, you have a big problem getting to it.. I took the rear housing off once (never again!), Now I'm taking the water pump off to fix a leak. The water pump is run by the timing belt, so the front of engine needs to be stripped down, and the timing belt removed to take off the water pump. That metal pipe is held in place by a bracket with one bolt on the rear of engine; it may require taking the lower intake off (again) to get to both of those pesky o-rings. I hope you don't have the same problem, and if you have the 4 cylinder engine, the thermostat is a snap to replace, plus you don't have that crazy plumbing problem.

If the bottom hose pipe is not as hot as the top hose pipe then you have a thermostat problem, but mak sure the radiator fan comes on when the temp reaches half on the guage.

ITS EVAPORATING AWAY.YOU NEED 50/50 WATER AND ANTIFREEZE.WHEN YOU MIX IT HALF AND HALF.IT RAISE BOILING POINT.

Yes, there is a "bypass outlet" coolant hose that connects from the water pump inlet pipe (metal pipe that runs from back of water pump along engine block to lower radiator hose) to the intake manifold.

I am not sure about the "black box" - not enough detail.

It should have a lower hose also. Or you could check around the water pump, they have a weep hole on it and they usually leak if the pump is bad.

check the bottom hose u may be leakening radiator flued and also check around the water pump if u see water then u need to change the water pump and if you see a leake at the bottom then change the hose.