Engine is overheating and heater has stopped working

The engine was replaced in my vehicle. It worked fine, but now the a/c isn't working. I do a little car repair and I discovered that there's no freon. What do you suggest that I do from here?
Experienced mechanics share their insights in answering this question :
If the engine was replaced and the AC refrigerant system was drained then the system should be put under a vacuum for a minimum of 30 minutes to ensure all moisture is boiled out and then leak tested to ensure system integrity. An AC system can be injected and charged to see if there are leaks. Now the AC system can build pressures in excess of 250 psi along with fact that refrigerant can cause serious frostbite injury if exposed to the skin so only a certified mechanic should service an AC system. Generally, AC system charging information will be located on a service label under the hood of the vehicle. You may want to enlist the help of a mechanic, such as one from YourMechanic, who will have the equipment and certifications to service, inspect, and diagnose your AC system.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

If your coolant level is a-okay, but your car heater is blowing cold air and your engine is overheating, then you have a clog in your cooling system. Conversely, if your engine temperatures are unrealistically low after a drive, your thermostat is likely the culprit.
The most common reasons a Volkswagen Golf SportWagen heater isn`t working are a broken heater blower motor, a problem with the thermostat, or a failed heater blower motor resistor.
There are two main reasons for this. Either there is a problem with the thermostat in the heating system or the heater core has a blockage or air in it. To see which of these two problems is causing the fault, drive your car for a while and get it up to its working temperature.
One common reason engines overheat while idling is a faulty or broken cooling system. This could include problems with the radiator, water pump, or fan belt. If any part of your car`s cooling system is not functioning properly, your engine may be at risk of overheating.
If an engine “feels” cold, or “normal” but the dash gauge shows overheating, you could have a faulty temperature sensor and/or gauge. No cabin heat could be due to low coolant, blocked passages, faulty heater control valve and/or faulty blend door(s) in the dash ventilation network.
Re: Engine overheating but radiator is cold

This could also be a blown head gasket. Reverse flow your radiator(Also check if the radiator is flowing water easily) and remove thermostat and run without thermostat. If problem persists, probably blown head gasket.

Low coolant: Whether caused by a leak or water evaporation, low coolant is the most common source of poor heater output. Thermostat: A stuck-open thermostat prevents the engine (and coolant) from heating up. Heater core: A clogged heater core restricts coolant flow, giving up little or no heat.
Your Filter`s Dirty

Over time, debris, dust, and allergens build up on these filters, which eventually causes them to clog. So if your furnace is blowing cold air, you`ll want to check your air filter. Once you`ve taken it out, hold it up to the light. If you can`t see any light shining through, you need to change it.

If your heater doesn`t start, chances are the problem stems from having a dirty furnace. Having dirt on your blower motor or flamer sensor could render your furnace unable to perform. When the blower motor is too dirty, it won`t pass enough cool air to the heat exchanger, leading to equipment failure.
So, if the coolant gets hot enough to boil, it may cause hoses or the car radiator to burst. Also, pistons may swell up and scuff or seize in their bores.
There`s an issue with the radiator – Another one of the most common engine overheating causes is a result of issues with the radiator. Overheating can occur whether it is due to a blockage, a leak, or problems with the radiator fan.
Coolant/antifreeze is added to a vehicle`s cooling system, which circulates the fluid throughout the engine and radiator to prevent overheating. If your vehicle`s cooling system is functioning properly, it will effectively reduce the heat produced by the engine and keep everything running smoothly.
If you think the cause for your car heating not working is related to the blower fuse, be sure to replace it with one of the same amperage. The fuse may have blown due to age, or it may suggest an underlying problem. If the replacement fuse (of the same amperage) does not blow, you may well have identified the problem.
If your blower only works on the highest setting, your blower motor control module probably needs to be changed. If the fan isn`t working, you probably need to have the blower motor fixed or changed. If the air coming through isn`t hot, the heater core is probably clogged.
Here are some of the most common causes of why air doesn`t flow out of your vehicle`s vents: Your air intake is clogged, meaning that air isn`t getting in from the outside at all or isn`t circulating properly. There is a blown fuse in the ventilation system. Electrical issues such as a bad relay.
Low Coolant Level

The coolant (usually a mixture of water and antifreeze) in your engine doesn`t just work to keep the engine from overheating: It`s also the source of heat supporting the heating system. If there isn`t enough coolant in your system, the heater core will blow cold air into your car.

Can you top your coolant up with water? Coolant should only be topped up with water in case of an emergency when the coolant liquid level is lower than it should be. While topping up with water will help you get safely to the nearest RAC Approved Garage and identify any issues, it shouldn`t be relied upon.
Don`t panic, but do act quickly—Take immediate steps to retain heat in your house: close curtains, block under-door drafts, hang blankets over doorways, etc. Use other heat sources—If you have other ways to heat your space, such as fireplace, propane space heater, or electric heater, use them.
A blocked heater core might restrict coolant circulation, causing the engine to overheat. In any case, keep an eye on the temperature monitor if you decide to drive with a blocked heater core.
Standard thermostats: Enlist a friend or family member to assist, Position one person by the thermostat and one person by the furnace. Slowly turn the thermostat from off to heat and increase the temperature. Both the thermostat and furnace should make a sound.
Across almost all models of cars and trucks, the number one cause for a vehicle`s heater to stop working is a faulty or broken thermostat.
One way to check for proper coolant circulation is to check the upper and lower radiator hoses. The upper radiator hose should be hot, around 190–200 °F. (The safest and most accurate way to get this temperature reading is with an infrared thermometer.)
When a water pump completely fails, it is no longer able to move coolant through the engine; this causes it to overheat. If you see steam, pull over immediately and call your mechanic for assistance — continuing to drive with an overheated engine can damage it to the point that it will need to be completely replaced.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Honda Civic 2008. AC stopped working suddenly and engine check light came ON for a day.Next day AC worked and no engine light.
ANSWER : Hi there. In both cases, when an AC system is not working and a warning light is coming on the dashboard, typically a professional mechanic will complete the same initial inspection, which is to download the stored error codes that triggered the warning light initially. This tends to give them an idea as to what is causing the problems. This could be something as simple as an electrical relay that is faulty or loose or an indication of a computer related "glitch". Either way, the best way to move forward is to have a professional mobile mechanic complete a check engine light inspection.

Windshield wipers stopped working. They’ll suddenly stop working then suddenly start working again. Has been happening for a week.
ANSWER : The problem you are describing likely stems from an intermittent electrical fault in the wiper circuit. The windshield wiper system uses a small electric motor to move the wiper arms that you see on the windshield. That electric motor is controlled through a switch, relay, fuse, and wiring. One, or more, of those electrical components has failed although it is also possible that the mechanical arms are binding (seized, if the lubricant has dried out) thus causing the electric circuit to the motor to overload. Regardless of the underlying fault, if you request a non functioning wiper diagnostic/repair, the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Just replaced head gasket, changed crack sensor new plugs. The check engine light is on, but dim, the only other light that the dash is a normal battery indicator. The fuel pump is not running when switch is turned on, the power windows don’t work, it turns over but not firing. It’s like only one part of the system is working. Also the heater fans work even if the switch is off.
ANSWER : I would first look at the diagnostic trouble codes. Those codes are available because the check engine light is on. If the fuel pump is not running (momentarily) at key on, that fault alone will prevent the car from starting as there will be no fuel pressure. Pump output and pressure can be directly tested and you can also check for electrical power to the pump. To find out why the engine will not run, the recommended diagnostic is a no start diagnostic. If you request that service, the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Car overheating, rocking while idle and heater stopped working. 2000 Toyota Camry.
ANSWER : Hi there:

Anytime there is major damage done to an engine; the risk of having a mechanical failure in the future is very likely. It’s very possible, if your engine is overheating, but not leaking coolant and the engine stopped running that the head gasket may be damaged. However, without being there to physically inspect your vehicle; that’s simply a guess. I’d suggest that you contact a local mobile mechanic to complete a car is overheating inspection first; so they can determine what is causing this issue you’re having; and recommend the right repairs.

The engine stopped working suddenly
ANSWER : BMW has a TSB (technical service bulletin) on this. A faulty oil level sensor can cause this, as the power to this sensor is shared with the transmission range selection switch. If the transmission range selection switch loses power, the engine computer cannot verify that the transmission is in Park. Therefore, the starter will not be allowed to be engaged.

Another possibility is a problem with the EWS (immobilizer circuit) or with the ignition switch.

To begin diagnosis, you will want to have the fault codes read out of the engine computer and go from there. You may want to enlist the help of a mechanic, such as one from YourMechanic, who will have the tools and equipment to carry out a diagnosis of your no start issue and recommend the best path of repair.

An inconsistent starter motor that occasionally works perfectly now will not work. Then engine will not crank at all.
ANSWER : Hi there. It is possible for the starter to fail. But before replacing the starter, make sure that the battery cables are tight and clean. Then check the starter relay and make sure that the relay is clicking. If the relay is not clicking, then check for power to the relay. If there is power to the relay but there is no click, then the starter relay would need to be replaced. If there is no power to the relay, then either the wiring from the relay to the ignition switch has a break in it or the ignition switch is failing. If there is power to the relay and power to the starter motor, then the starter motor needs replaced. If you need further assistance with your no start issue, then seek out a professional, such as one from Your Mechanic, to help you.

My 2010 kia blower fan stopped working but was fine last week. This occurred a few times in past. Works fine then stops blowing ag
ANSWER : The blower switch and the plug connection on the back of the switch, as well as a faulty blower motor are likely, too. I would check the blower motor first as you can easily power the motor directly to see if it runs. If the circuit includes a blower motor resistor block, of course be sure to check if the resistor block has continuity (specified resistance in ohms) at each position. If the blower motor runs, I would check the switch as occasionally there will be a bad connection at the switch that eventually causes the blower not to work. The relay is easy to test and if it works consistently as commanded, you can assume there is no intermittent fault. Obviously, check the fuse in the circuit, too, but if the fuse is bad, that means there is a problem in the circuit that will have to be repaired. Fuses blow due to electrical faults (e,g., short circuits). If you desire, a certified mechanic from YourMechanic can diagnose the problem you are having in an electrical component diagnostic.

2004 Toyota Highlander @147000 miles. Just had bolt problem on engine. Got it back after 1400 and now my heater is not working correctly.
ANSWER : Hi there. If your heater is not producing enough heat, then first check the coolant level and make sure that its full. If the level is full, then check the heater control valve and see if its working. Feel the heater hoses on both sides of the valve and if one side is cold and the other is hot, then the valve is not working. If both are cold, then the thermostat is stuck shut. If they both are hot, then the heater core could be plugged up. If you need further assistance with your heater not working, then seek out a professional, such as one from Your Mechanic, to help you.