No heat engine overheating

If the heater core hoses are hot but there is no heat coming out of the vents, and the vehicle is also overheating, there are several possible issues that could be causing this problem. Here are a few things to check:

1. Coolant level: Check the coolant level in the radiator and reservoir. If the level is low, it could cause both the overheating and lack of heat. Top up the coolant to the correct level and check for leaks.
2. Thermostat: If the thermostat is stuck closed, it could be preventing coolant from circulating through the engine and into the heater core. This could cause both the overheating and lack of heat. Consider replacing the thermostat if it is found to be faulty.
3. Water pump: The water pump circulates coolant through the engine and heater core. If the water pump is not working properly, it could be causing both the overheating and lack of heat. A mechanic can test the water pump to determine if it is functioning correctly.
4. Heater core blockage: If the heater core is clogged or blocked with debris, it can prevent hot air from circulating through the cabin. This could cause a lack of heat. Flushing the heater core may help remove any blockages.
5. Cooling system blockage: A blockage in the cooling system, such as a clogged radiator or hose, can prevent coolant from flowing properly and cause overheating. Have a mechanic inspect the cooling system to determine if a blockage is present.

These are just a few possible causes of the overheating and lack of heat. It is recommended to have a qualified mechanic inspect the vehicle to diagnose and repair the issue.

Coolant level? Is water pump working? Is thermostat stuck? Are cooling fans running? Do radiator hoses and heater hoses feel hot? You can either provide this information or take your vehicle to a qualified professional and have it properly diagnosed and repaired.

First The heading says 99 Taurus but the question says 99 f-150. Second, are you saying that the engine is overheating? The heater won't work if the level of coolant is low and that would explain overheating. The thermostat controls the temp of the heat, so if it is stuck closed then water can't circulate to the heater and the vehicle would overheat, but this is unlikely.

the other answers seem to concentrate on a non-working heater. Good luck with this problem.

Possible, with rad cap off, let vehicle idle until coolant fan comes on then shut vehicle off for 30 minute cool down. Top up rad, install cap and drive and recheck heater operation and any overheating.

the knock sensors are attached outside each cylinder and sense when detonation in the cylinder occurs and signals the CPU to increase /decrease the air/fuel ratio for the engine rpm and load. IF they are not working then you will get a rattle in the engine because the CPU is not getting compensating information. This rattle if not stopped will cause engine damage. The o2 sensor problem will have to be addressed also as the sensor is telling the CPU that the air/fuel mixture is not right and it will run lean or rich and the economy will suffer.. Low heat from the heater signifies that there is a air lock in the coolant system that you may have to remove by pressure bleeding the system

Stop leak can cause the radiator ports to get clogged. But if your car isn't getting heat, it's probably your heater core. The heater core is usually burried in the firewall between the engine and where you or your passenger put your feet

But is the engine overheating ?
Electric cooling fans will sometimes come on after a vehicle is parked,
(It actually heats up when stopped), but not when it is rolling down the road
because the movement is applying some cooling effect to the engine.
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If the engine is not actually overheating, then the fans may be working
normally. Also, make sure your water/antifreeze mix is correct by using a
specific gravity tester. It is a tube with 4 or 5 balls, some of which will float
to give you a reading. Contrary to popular belief, More is not better when it
comes to antifreeze/coolant. It needs water to work properly. Too strong a
mix will actually make your vehicle run cold so that the temp sensors and
heater will not function properly. The engine will not achieve proper operating
temperature and may actually damage some of the components by running
it cold, affect timing, spark, etc. This could also cause the symptoms you
describe. The engine would not actually reach the proper heat threshold
until you added the extra demand of the AC heat transfer. But the first criteria
would be whether the engine is actually overheating / or in normal range .

When your not feeling heat coming from the heater it usually means that the coolant level is too low in the radiator. It sounds like you have a coolant leak somewhere which is causing your overheating problem. Fill your radiator and let the engine run for about a half hour with the radiator cap on tight. Then turn off the engine and check for any leaks under the van. If you don't see any leaks under the van then see if the carpeting is wet on the passenger side of the vehicle. If the carpet is wet and it smells like anti-freeze you have a heater core that is leaking. I hope this helps you. :)

check your radiator level, as stupid as it sounds my 01 celica didn't have heat for 2 years. I was thinking it was the heat flap or something because when I drove the heat would start working and when I stopped it would stop working. Yesterday the car overheated so I checked the antifreeze and added about half a gallon. The car stopped overheating and as a side result the heater started working normally again. I did head slap and went on with life. Most vehicles have the heater core low to the floor but in the celica it is actually higher than the motor which means if fluid is at all low it won't work as it turns out.

you more than likely have an air lock in the cooling system you need to bleed the system of air, has the coolant just been replaced?
does the engine fan come on to stop the vehicle overheating?