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Volvo S70 Heater Core

Keep Cool and Diagnose a Bad Volvo S70 Heater Core

With the press of a button, you can get hot air blowing from the air conditioning vents inside your Volvo. This is made possible by a heater core that uses your hot engine coolant to warm your cabin in a way that's similar to how your radiator cools it down. As the hot coolant travels through its tubes, its fins begin to dissipate the heat into the outside air while a fan blows the heat out to the cabin. This may seem simple, but you will surely appreciate this on a cold night or during a winter's drive. You will need to ensure that your Volvo S70 heater core isn't showing any signs of wear and tear so that you can confidently drive outside when the temperature's freezing. Otherwise, the frightful weather will eventually get inside your vehicle and cause goose pimples, shivering, hypothermia, or even death.

Cracks and leaks

Cracks in the core or in its heater hose will cause the engine coolant to leak out. Apart from inefficiently heating up your S70, a leak can also cause trouble for other parts of your car. Because the heater core is located under the passenger's side of the dashboard, the coolant can soak your carpets. If you notice a wet spot in this location that produces a sweet smell, a fogged-up windshield, a greasy film on the windows, and a low amount of coolant in the reservoir, then you definitely have a leak on your hands. You'll need to replace the heater core and/or your hose, refill the coolant, and clean and dry your carpet when this happens.

Slow warm up, noises, and erratic functions

A malfunctioning Volvo S70 heater core has many signs that may be unnoticeable until you press that heater button. These include taking more than ten minutes for your cabin to warm up; a grinding, swooshing, or clanking sound that you can hear whenever your heater is turned on; "heated" air that isn't hot enough; and the continuous fluctuations of the vent's temperature. If you notice these signs, then you'll need to replace your heater core at once.

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  • Stopping Clogs and Leaks in Your Volvo S70 Heater Core 27 February 2013

    Your Volvo S70 heater core is the reason why you can simply press a button to let hot air come out of the air conditioning vents into your cabin. However, it can suffer from clogs and leaks that will make it work harder and less efficiently. Ensure that your heater core performs at its peak by stopping these problems at once.


    Clogs in the heater core

    Flush the heater core to remove clogs.

    By reversing the flow of fluid inside your heater core, you might be able to dislodge any particles that have accumulated in the engine coolant. This is a messy process, so be sure to place drain pans underneath your Volvo to make cleaning up easier. Then, you can remove the clamps that keep the heater hoses joined to the engine. These hoses connect the heater core to the engine, and you'll need to lift their ends up to prevent the coolant from leaking. After removing their clamps, place the inlet hose into a bucket before spraying water into the outlet hose until water flows out to the bucket. Finally, connect the heater core and engine by clamping the heater hose again before refilling the coolant.


    Prevent clogs with filters.

    To prevent clogs from forming in your heater core in the first place, you can install a filter inside the heater hoses. These metal mesh nets will catch the rust particles and prevent them from forming clots. But, you'll need to clean it out every once in a while so that the coolant can still flow through their net.


    Leaking heater core

    Repair leaks with an additive.

    Apart from replacing a cracked heater core and hose, you can also stop the coolant from leaking onto the floor with the help of a stop-leak additive. Pour some onto your radiator, and then run your engine to distribute it throughout the cooling system. If this doesn't fix the problem, you'll need to remove the hoses attached to the heater core and splice new one between the two. This will divert the coolant fluid temporarily while you get a new heater core and its hoses.


    Prevent leaks by changing the coolant.

    Did you know that over time, your engine coolant can change its chemical composition from an alkaline base to an acidic one? When it does, it can corrode the rubber hose that connects your heater core to your Volvo's engine, as well as the core itself. This causes them to crack and leak out the sweet-smelling coolant. To avoid this, you need to change your engine coolant every 40,000 miles. Just drain the old coolant from the radiator and into a pan. When all of the coolant has gone out of your car, you can then create a mixture that comprises of 60 percent coolant and 40 percent water. Add this to your S70 when it's cold, and make sure to top it off regularly. Don't forget to dispose of the old coolant mixture according to your area's regulations since it's quite poisonous to animals.