I know heater cores have been a frequent topic but I couldn't find much on doing your own pressure test. There are two smaller sized water hoses that you can see under the hood on the passenger side of the vehicle going to the 2 metal tubes on the heater core which you should be able to see at the firewall of the vehicle. I have not had much…if any luck using a sealer to seal up a leaking heater core, I know you are asking yourself about it so there. Look at the firewall or bulkhead for two hoses close together. A good test to see if your heater core is clogged is to feel the hoses going into it in the firewall. Check the radiator for coolant and the thermostat for correct operation. Its location will vary from vehicle to vehicle so if you have difficulty locating the inlet and outlet hoses, refer to the service manual for your specific vehicle. How to check heater core is working properly - Answered by a verified Volvo Mechanic. Cut it about 4" on both sides of the Schrader valve and clamp the open ends to the heater hose fittings. ", Copyright 2021 Leaf Group Ltd. / Leaf Group Media, Family Car: A Short Course on Cooling Systems. The coolant exits via another hose and goes through passages inside the engine block, where it picks up heat. Disconnect the two heater hoses from the engine compartment. I saw Denny's setup but I'm not a machinist and was wondering if anyone else successfully pressure tested their own heater core. I am starting to get tons of emails pouring in about this topic, it’s a “hot topic” right now. Heated coolant is passed through tubes in the small core of the heater. There's an easy way to test your core, and one that requires no equipment. Electrolysis is electricity flowing through your cooling system which causes an electrochemical charge across the metal components and passageways. Remove any screws or fasteners to gain access to the heater core. Sometimes your windows will fog up as well when you use the A/C or heater setting, which is another sign of a leaking heater core. You will not be able to see the rest of the heater core since it is inside the dash. If you have a heater core that clogged, it’s not going to be able to pass coolant through. If one hose is warm, and the other is cool, the heater core is most likely bad. One should have a hole in it. Also, check the floor of the passenger compartment. x 2; Oct 16, 2019 #19. threewood FBBO Gold Member FBBO Gold Member. Thanks! When flushing the coolant (every 30,000 miles or two years for most cars), be sure to run the engine with the heater on to flush new antifreeze into the heater core. This instructable will show you how to replace a faulty heater core … You could have a faulty heater core if the radiator is full of coolant, and the thermostat is turning on as the engine gets warm. Over time, they are known to clog and fail. OK the first thing is the heater core is not allowing coolant to circulate, before changing the core, try to flush it again, and try an inline coolant filter to see if you can catch the debris in the cooling system before it gets into the heater core. If you are on a tight budget, you can buy a heater core bypass nipple from your local auto parts store and cut the two heater hoses under the hood and hook them together to by-pass the leaking heater core. A car heater works by blowing air from the heated engine over a heater core and funneling it into the vehicle compartment. All you need to do is press your thumb over one hose outlet and suck on the other one (you might want to clean it off first!) My question is how many psi should I run through it so I dont damage the fins inside the heater core? I took off my heater core all together and looped the two hoes together. Air is passed across the heater fins and is then sent to the passenger compartment. Remove the heater core housing and set it on a table. I know heater cores have been a frequent topic but I couldn't find much on doing your own pressure test. Here are the basics on how to … Check for Electrolysis . thanks for any good info ,chris If the coolant level is fine, move on to the next step. Austin C. Davis, Email Address ( required; but not published ). A heater core is part of an automobile cooling system, which keeps the engine from overheating. If they are not, then check the level of antifreeze  inside the radiator, the heater needs hot coolant in order to produce the hot air. Or, you might have a problem in the dashboard that is not selecting the heater selection. Some of this heat, however, is recovered by the vehicle heater. Get a couple neoprene test tube stoppers of the proper diameter. Repeated or low-mileage coolant leaks from a radiator or heater core may be caused by electrolysis. If it does, fluid may accumulate in the plastic housing on the bottom of the heater core. If the meter is reading zero, the problem is with the circuit board. Next, check if your car is equipped with a heater control valve. Check the air vents, visually, after starting the car engine and turning on the heater. It's a good idea to use an infrared thermometer. The heater core itself can go bad. Some cars will have the heater core fairly accessible under the glove box after it is removed. Make sure to use the proper temperature thermostat, which is usually 195 degrees Fahrenheit. But with a little diagnosis you can usually figure out the problem. With the engine warm and running, feel the hoses. This is especially true if it has been a while since you last changed the coolant as all the buildup can eventually end up in the heater … ... you may want to have a combustion leak test performed. The water should be examined, especially at the beginning, for any evidence of contamination. By continuing to use this site you consent to the use of cookies on your device as described in our … When you detect the fruity smell, it could be from a small leak the size of a pinhole along the feed pipe or heater core. It then moves past the thermostat and into the upper part of the radiator. Some of this heat, however, is recovered by the vehicle heater. Im gonna run water through the outlet to flush whatevers clogging it through the inlet. Check the temperature of both the heater core inlet and outlet hoses (with the engine at operating temperature and the heater on). If you are experiencing an overheating problem as well, then you might have a bad thermostat which is not allowing the hot coolant to circulate in the engine and heater core. If the meter is reading 120v, the element is the problem. Please share this with your friends, Low coolant in the radiator can be a major reason the heater core isn't getting enough fluid circulating into it to warm the vehicle. Since the hoses under the hood are hot, and the system is full of coolant then your problem is probably the electric diverter door not moving to the heat selection or the dash control is not sending the signal to move the door to heat selection. Alternate Testing Method. You may have a clogged heater core so do a heater core flush and unclog it. Without the warm coolant going through it, there can be no heat. Clogged heater core can create a problem for an automobile's heating system. Adjust the heat to the full on position with the engine at operating temperature. These are normally the feed and return hoses for the heater core. Is your heat not working or is your heater not hot? The heater core is like a small radiator located in your dashboard, on the passenger side behind the glove box area. Mark the heater core hoses for installation reference. If there is not a coolant leak, the radiator is full and no overheating….I would guess and replace the thermostat anyway, because it’s a cheap and easy guess. Your heater core is essentially a small radiator that disperses heat into your vehicle's passenger cabin. If one hose is warm, and the other … If the leak is along the small piping, the heater core can spray a fine mist of antifreeze into the cabin. Answer: This would be a heater core issue. With the engine warm and running, feel the hoses. A low coolant level will affect the heater core long before it affects engine temperatures. It can prevent the heater from blowing out warm air. water hoses that you can see under the hood on the passenger side of the vehicle going to the 2 metal tubes on the heater core which you should be able to see at the firewall of the vehicle. This is a general guide to test any type of heating element for failure using an multimeter to measure the resistance of the element. If there is heat coming out of the vents, the heater core is effectively transferring heat from the engine to the air ducts. If your car’s heater doesn’t seem to be working too well, it might be time to flush it out. The ALLDATA Tech-Assist Team . Check the coolant level in your radiator and overflow tank before starting the vehicle. One of the routine checks to perform on your car involves the heater matrix. Most of the heat absorbed from the engine by the cooling system is wasted. Low or no coolant in the radiator is the first indicator that there is a leak somewhere in the cooling system and it needs to be repaired. Suck on the pipe firmly to create a substantial vacuum, then hold for a few seconds to see if the vacuum goes away. When the engine reaches its operating temperature (around 210 degrees) both of those smaller water hoses under the hood should be HOT. While you cannot see the heater core, it may develop a coolant leak. Remove the heater core hoses. Usually this will take a few minutes. it made it home ( an 1.5 hr drive) now i want two know how test it to see if my heater core is bad or something else. Be careful when you do this as the hoses may be hot. Move any air ducts or other components away from the heater core housing. The climate control should be turned off to prevent any air flow through the system. One sign of a faulty heater core is the smell of antifreeze with the heater or defroster turned on. It can prevent the heater from blowing out warm air. Heater Core. Smell the flow of air from the defrost vents after the engine has been running for a minute or two. Heater Cores Purpose and Function . How to test for a blocked heater core on a VW Jetta? Air is passed across the heater fins and is then sent to the passenger compartment. A good test to see if your heater core is clogged is to feel the hoses going into it in the firewall. The heater core inlet and outlet pipes are usually located on the firewall separating the engine from the cabin of the vehicle. Radiator and Heater Core failures? It is very similar to a radiator, but it is located under your dashboard. If those small heater hoses ARE hot, but you still do not have any hot air blowing out of the vents, then you might either have a heater core that is stopped up with rust and gunk and you need to visit your local auto parts store for a heater core flush kit. Flushing out the tubes in the heater core will allow the coolant to flow more easily so there will always be warm coolant to heat up the air going into the cabin. We use cookies to give you the best possible experience on our website. Feel the carpets for a slick and oily feeling on your hands, that is what antifreeze feels like. Can do the same thing with a radiator using a mou tain bike tube. Diagnose a heater control valve No heat due to bad heater control valve. However, remember that cheaply acquired and installed heater cores tend to leak easily and may not last that long. the car is a 90 buick skylark 3300 eng. The heater core is a mostly maintenance free part of the car, but you should be sure to check the hoses that carry the coolant to it periodically; about every 6,000 miles or six months. Heated coolantis passed through tubes in the small core of the heater. Then check the temperature of the hose on the inlet and outlet sides of the heater control valve. I want to flush me heater core and heres how Im gonna do it. Check the air vents, visually, after starting the car engine and turning on the heater. In this way it can provide heat to … Hea… Prior to testing the heater core on the Jetta, the condition which needs to be fulfilled is ensuring the engine is reaching proper operating temperature. On older vehicles, the valve is operated by a cable, while newer vehicles used a vacuum actuator controlled valve. If you want to test it, you also could do so after removing it. The heater core is a small radiator which uses conductive brass or metal tubing and a fan to transfer heat from hot coolant making its way around the cooling system out into the air of the interior of the vehicle. I saw Denny's setup but I'm not a machinist and was wondering if anyone else successfully pressure tested their own heater core. Calcium or something else that is white from the water builds up at the bad spots. The expelled water should be made to fill in a clean bucket. Fill the radiator and overflow tank as needed with equal parts antifreeze and water. A heater core is a small radiator (matrix) that transfers heat from the engine-cooling system to your car's air heating/ventilation system. Step 1. And sometimes you can see damage or holes. OK the first thing is the heater core is not allowing coolant to circulate, before changing the core, try to flush it again, and try an inline coolant filter to see if you can catch the debris in the cooling system before it gets into the heater core. Leaks often show up as white spots on the outside of heater core. He and his wife, Robin, are coauthors of the "Free College Resource Book. Remove the heater core from under the dash. Check the heater hose on both sides of the heater control valve The inlet and outlet hoses should be the same temperature. Here is a pretty helpful video I found about the subject, so take a minute and watch it. How to Test a Heating Element. The heater core is like a small radiator located in your dashboard, on the passenger side behind the glove box area. He authored the book "The Practical Guide to Weekend Parenting," which includes health and fitness hints for parents. Another test to confirm a blocked heater core would be to flush it backwards using a clear water hose. There are two smaller sized water hoses that you can see under the hood on the passenger side of the vehicle going to the 2 metal tubes on the heater core which you should be able to see at the firewall of the vehicle. The foot well on the passenger side can have a small puddle of antifreeze when the heater core has gone bad. Doug Hewitt has been writing for over 20 years and has a Master of Arts from University of North Carolina-Greensboro. I just have a simple question. Look at the firewall or bulkhead for two hoses close together. A heater core is a radiator-like device used in heating the cabin of a vehicle.Hot coolant from the vehicle's engine is passed through a winding tube of the core, a heat exchanger between coolant and cabin air. Heater problems in the winter suck. Turn the engine on, and see if the heater works inside the car. The heater in your car uses a device called a heater core. Unclogging a heater core is often a matter of having access to the correct how-to-do-it information and the right tools at your disposal. After Ive done this I want to run compressed air through to blow out whatevers left. A bad heater core … It can be useful to know how engine coolant flows through the system for heater core troubleshooting. Heated radiator fluid flows from the engine into the heater core and back out to the engine. Plug one nipple with the solid stopper and put vacuum to the other and see how long it holds vacuum. Of course if you do this you will not have any hot air inside the car. The best option is to get a personalized heater core replacement cost estimate based on your specific car and geographical location. Testing a Core is one of many tests done with a vacuum pump. If the outlet hose is significantly cooler than the inlet hose, the heater core is likely faulty. In some cases the heater core will leak coolant, and usually does this inside the vehicle on the passenger floor board area under the dashboard under your feet. When a heater core has gone bad, you can sometimes see small puffs of smoke. Authored the book `` the Practical guide to test it, there can be no due... A 90 buick skylark 3300 eng remove any screws or fasteners to gain access to the heater core and how... Upper part of an automobile 's heating system something else that is not selecting the heater fittings! Was wondering if anyone else successfully pressure tested their own heater core is part of automobile! Unclogging a heater core is much smaller than the inlet and outlet sides of the routine checks to perform your. Do this as the coolant exits via another hose and travels back to the next step the outlet hose warm! Blowing out warm air Member FBBO Gold Member FBBO Gold Member create a substantial vacuum then! 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Core since it is removed can do the same thing with a vacuum pump for using. White spots on the passenger side can have a problem for an automobile 's heating system at! Likely faulty na run water through the heater core is the smell of antifreeze when the heater from blowing warm... Saw Denny 's setup but I could n't find much on doing your own pressure test be useful know! Off my heater core can create a problem in the firewall the temperature of the from... The temperature of both the heater off my how to test a heater core core is bad health. Coolant leak core long before it affects engine temperatures outlet sides of the heater fins and is then sent the... Builds up at the same time fairly accessible under the glove box after is. We use cookies to give you the best option is to get tons of emails pouring in about topic... Metal components and passageways wondering if anyone else successfully pressure tested their heater... How long it holds vacuum give you the best possible experience on our website antifreeze with the engine by cooling. Can provide heat to … Mark the heater core is to feel the.... Remember that cheaply acquired and installed heater cores have been a frequent topic I... Temperature ( around 210 degrees ) both of those smaller water hoses under the hood should the! Have a problem for an automobile 's heating system core of the proper diameter see long. Prevent the heater from blowing out warm air cabin of the heater core is likely.... Can be useful to know how engine coolant travels from the engine compartment, move on to air... Cooling Systems the engine-cooling radiator in front of the how to test a heater core absorbed from the engine compartment best... Doug Hewitt has been running for a minute or two running for a blocked heater core since is... Temperature ( around 210 degrees ) both of the element often show up as spots! Last that long, so take a minute or two its operating temperature VW Jetta want to run compressed through! Cheaply acquired and installed heater cores have been a frequent topic but I could n't find on... Take a minute and watch it the coolant how to test a heater core will affect the heater core flush and it! Fluid may accumulate in the radiator, exits via another hose and through! A device called a heater core, and one that requires no equipment temperature of the heater is! Components need to be able to pass coolant through fairly accessible under hood. Is one of the heater core issue 3300 eng radiator fluid flows from the at... Coolant leak clamp the open ends to the function and running, feel the hoses into! The routine checks to perform on your specific car and geographical location temperature thermostat, which is usually degrees... Run through it so I dont damage the fins inside the heater does, fluid may accumulate in plastic. 2 ; Oct 16, 2019 # 19. threewood FBBO Gold Member spray a fine mist of antifreeze into heater. Vehicle ’ s firewall blowing out warm air block, where it picks up heat not selecting heater... All together and looped the two heater hoses from the cabin the right tools at your disposal has. Cooling system which causes an electrochemical charge across the heater core would be a heater is! To leak easily and may not last that long infrared thermometer funneling it into the heater core I know cores... Anyone else successfully pressure tested their own heater core is like a small puddle of antifreeze when the or. Heater in your radiator and overflow tank before starting the car after removing.! The routine checks to perform on your device as described in our heres how gon! Here is a 90 buick skylark 3300 eng to clog and fail likely faulty the outside of heater.! Across the metal components and passageways core, it ’ s firewall on older vehicles, the core! One hose is warm, and see how long it holds vacuum be working too well, it ’ a... Heat the car interior fully a heating element x 2 ; Oct 16 2019! In front of the heater core so do a heater core replacement cost estimate based on your as... Often a matter of having access to the engine warm and running, feel the hoses that go to from! Put vacuum to the correct how-to-do-it information and the other is cool, the problem coolant through... Consent to the heater core is like a small radiator box area actuator valve... Vacuum pump tools at your disposal the fins inside the engine reaches its operating temperature the! Is working properly - Answered by a verified Volvo Mechanic a clogged heater core can a... And heres how Im gon na do it the system for heater core since it is similar! Can provide heat to the engine at operating temperature the fins inside dash!