My Kia is leaking coolant when I switch off the engine

I suggest you check the pipes to the rear heater which are prone to corrosion and mystery coolant leaks.

The pressure cap on the engine coolant filler neck can leak when the housing becomes corroded and rough so the rubber washer no longer seals or the rubber washer becomes perished - note the cap should seal in two places so coolant expansion is pushed into the bottle and then sucked back when it cools but it won't do that unless the cap makes an airtight seal under the rim of the cap.

Im not quite sure what bypassing heater coil has to do with aircon leak, unless you mean there's coolant leaking from under dash, if coolant is leaking, remove hoses at firewall and follow them back to engine, you can use one of them to bridge from one to the other. Or put a connector between the hoses

if NO coolant in engine oil in block but ONLY in radiator- you have a internal leak in radiator- replace it BEFORE you get mix in engine...

A/C BLOWS HOT. Radiator in Kia is rather small it overheats quickly. I should have checked the simplest thing first which was the radiator coolant level. I had a slow leak in radiator it was losing coolant but not very noticeably. I initially took it to have the a/c system checked all was good,they referred me to an electric repair shop but all the fuses and relays were good. I don't normally check coolant level as it is checked by dealer when oil is changed,this is a 2nd car and I don't drive it daily. Since coolant level was dropping slowly the engine would not overheat,however coolant got low enough to trigger emergency a/c compressor shut down switch to keep engine from overheating. That's why a/c would cool for 10 mins. in the morning but then shut off. Simple fix I filled the radiator and overflow tank. A/C started working perfectly again. After doing this a few times I realized the radiator had a leak which eventually had to be replaced $700.00 parts and labor. Its all good now.

Try check ur radiator n engine possible there is coolant leak somewhere with the radiator or engine.. Also try check with a diagnosis computer for ur engine DTC is it showing Trouble code for over heating.. N the radiator coolant level dropped..

If you have a pressure reservoir I would replace the cap. When they wear out they will let the coolant out as you drive. Could also be a cracked reservoir. Fill it and cap it. Fill it to the top this time and start the engine. As it warms up, if coolant starts to come out the overflow. replace the cap. And if not you will have to hunt down the leak. If the car is not running bad, then you can rule out internal engine leaks.

p0116 is-- engine coolant tempurature ckt/range performance----- p0 128 is--coolant temp below thermostat regulating temperature. to fix these 2 codes are similar, change coolant tempurature sensor and thermotat all should be ok. make sure coolant in radiater is full. hope this helps you.

A code P0128 may mean that one or more of the following has happened:

• Low engine coolant level
• Leaking or stuck open thermostat
• Faulty cooling fan (running too much)
• Faulty coolant temperature (ECT) sensor
• Faulty intake air temperature (IAT) sensor

in this case i would suspect the water pump,it would not really show up in a pressure test ,put a paper liner under the car at night and see if any water shows up on it in the morning,if it is ok, then the water could be lnternal ie the engine is taking the water,but 2007 engine should not have this problem unless it has a very high milage.one more [simple] answer is the coolant leaking from a simple loose conaction and drying up before you see it ,but water leaves a trace so have a good look about the engine for that water mark,please rate this answer.adrian,,,,,,,,,,,

PO117 - Engine Coolant Temperature Circuit Low Input
PO325 - Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor)

Do you have a coolant leak?

Hello, my name is Mario.

1. Disconnect battery negative cable.
2. Drain engine coolant
3. Remove bolt and nut for thermostat housing
4. Remove the old thermostat
5. Put a new thermostat and gasket (Install thermostat into cylinder head with jiggle pin positioned up.)
6. Place thermostat housing
7. Fill radiator with engine coolant
8. Connect battery negative cable
9. Start engine and check for leaks.

Good luck