The Importance of Refilling & Bleeding the Cooling System After Replacing a Thermostat - Water Pump U (2023)

The Importance of Refilling & Bleeding the Cooling System After Replacing a Thermostat - Water Pump U (1)

Performing work on the cooling system can be laborious; however, auto technicians must ensure the entire repair or replacement is completed fully. After replacing a thermostat, the technician should ensure all air pockets are removed from the cooling system. Otherwise, the vehicle will be more likely to overheat.

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After replacing the thermostat, refill antifreeze. Leave the radiator cap off, and start the vehicle. Wait five minutes to allow all of the antifreeze to circulate throughout the engine. Turn off the engine, and allow the engine to cool. Recheck the antifreeze level, and top it off if necessary.

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Do I need to bleed cooling system after replacing thermostat? ›

After replacing a thermostat, the technician should ensure all air pockets are removed from the cooling system. Otherwise, the vehicle will be more likely to overheat.

What happens if you don't bleed your coolant system? ›

Over time, air can become trapped within your radiators, leading to cold spots and a less-than-optimal performance from your home heating devices.

Why do you bleed a cooling system? ›

Bleeding the cooling system removes any air pockets so the cooling system can work effectively. For example, the heat may not be as warm or work at all if too much air is in the heater core, since there will be less hot coolant emitting heat for the blower motor to push into the cabin.

What to do after replacing a water pump? ›

When you're done replacing a water pump, it's good practice to burp the cooling system to get rid of all the trapped air. Some thermostats have a small hole at 12 o'clock, and a jiggle pin which allows the air to escape (while preventing new air from getting in).

What should you do when replacing a thermostat? ›

How to Install a New Thermostat
  1. Turn Off Power to A/C and Furnace. ...
  2. Take a Picture of the Wires. ...
  3. Disconnect Wires from Old Thermostat. ...
  4. Put on the New Thermostat Mount and Connect Wires. ...
  5. Screw Faceplate Mount to Wall. ...
  6. Attach New Thermostat Face. ...
  7. Turn Power Back On to A/C and Furnace. ...
  8. Configure New Thermostat.
Oct 30, 2014

How do you fill and bleed the cooling system? ›

To raise your car, use a floor jack or park the car on the steep hill with the front upward. Fill Coolant:When your car is raised, fill the coolant as much as possible. If there are air bleed valves, open them simultaneously while filling the coolant. Close the valves when the coolant starts flowing out.

How do you burp air out of a cooling system? ›

Burping (so named because of the noise made by the bubbles of coolant exiting the radiator filler neck) is done with the radiator cap removed on cars without a valve. You wait for the car to warm up so the thermostat opens, and then the pressure of the expanding coolant being heated drives the air out.

Do you bleed a radiator until all the water comes out? ›

Yes, it is perfectly normal for water to escape when a radiator is bled. You'll likely notice some drips emerging when initially turning the bleed screw in an anti-clockwise direction. And water would pour out once the air was released, if the valve was to be opened fully.

What happens if you bleed a radiator too much? ›

You could risk scalding yourself with the hot air and hot water existing in the heating system. Even if you have had the heating turned off for a few hours, the radiators may not have fully cooled as the bleeding could result in the release of some very pressurised, very hot air.

Do you have to drain the coolant when changing a water pump? ›

It's a job that could take several hours, depending on what you drive. The first steps in removing any water pump are to let the engine cool off completely, and then drain the cooling system by either opening the radiator petcock or disconnecting the bottom radiator hose.

How long does it take for well water to clear up after replacing the pump? ›

Depending on the size and depth of the well and extent of contamination, pumping times will vary; it may take thirty minutes, or it could take several hours or days until the water runs clear.

What are the things you should do before you start to operate the water pump? ›

We've put a quick guide together to help you through the basic steps of priming your water pump.
  • Make sure the power is turned off. ...
  • Gain access to the pump system. ...
  • Check for damage. ...
  • Test a hose. ...
  • Open the relief valves. ...
  • Attach the hose. ...
  • Turn on the water and wait for it to enter the tank. ...
  • Turn the power on.

What are some of the common mistakes when installing a thermostat? ›

8 Mistakes People Make With Their Programmable Thermostat
Apr 27, 2018

What happens if you install a thermostat wrong? ›

Potential consequences of improper installation could include: Electric shock. Blowing a circuit breaker. Damaging the thermostat unit, the electrical system or even the AC/furnace unit itself.

Can you just replace a thermostat? ›

Replacing your thermostat is a simple, inexpensive upgrade

In most cases, you can replace your thermostat without having to make any other adjustments to your HVAC system. And if you're switching from a manual thermostat to a programmable model, the upgrade will often quickly pay for itself in future energy savings.

How do you bleed a radiator with a thermostat on? ›

How to bleed your radiator
  1. Turn off your heating. ...
  2. Use your radiator key to turn the valve at the top of the radiator. ...
  3. Retighten the valve once the hissing stops and only liquid comes out. ...
  4. Turn your central heating system back on.
  5. Check the pressure by looking at the gauge on your boiler.

How do I know if my air is trapped in my radiator? ›

Carefully check each radiator to ensure it has an even temperature across the whole surface area. If you do find any radiators that are cold at the top or hear any gurgling noises, it's a good indicator that there's trapped air inside and that you'll need to bleed it.

How do you know if your cooling system is clogged? ›

5 Symptoms Of A Clogged Or Bad Car Radiator
  1. Temperature Gauge Reading Higher Than Normal: The temperature gauge indicates the temperature of a car coolant. ...
  2. Radiator Leaking Coolant: ...
  3. Radiator Hose Troubles: ...
  4. Coolant Color Change: ...
  5. Radiator Fins Bent or Broken:
Jul 28, 2022

What is the most common cooling system problem? ›

One of the most common yet serious problems that develop in the cooling system is a radiator leak. A crack or leak from the radiator can lead to significant loss of coolant or antifreeze. Without these fluids present in the cooling system, air bubbles start to develop.

How do you burp coolant after replacing thermostat? ›

How to Burp the Cooling System
  1. Find the Radiator Cap or the Coolant Reservoir Cap. ...
  2. Replace Any Lost Coolant. ...
  3. Squeeze the Upper Radiator Hose to Remove Any Air Pockets. ...
  4. Look for a Bleeder Screw and Open It If There. ...
  5. Attach a Funnel and Let Air Burp Out of the Cooling System. ...
  6. Raise Coolant Fill Area as High as Possible.
Jun 3, 2022

How long does it take to fully bleed a radiator? ›

How long does it take to bleed a radiator? Typically, it only takes between 20 - 30 seconds to bleed a radiator. This can increase up to one minute, depending on the size of the radiator and the amount of air that needs to be bled.

Will bleeding radiators stop pressure dropping? ›

Yes. During the process of bleeding radiators, air is released from within them, which in turn reduces the pressure in your boiler system. Find out everything you need to know about the radiator bleeding process in our full Advice Centre blog, How To Bleed A Radiator.

Which radiator do you bleed first? ›

If your home has 2 floors you should begin bleeding the downstairs radiators first. It's also advisable to start with the radiator which is furthest away from the boiler. Once you've bled all the downstairs radiators you move on to the upstairs, again beginning with the radiator which is furthest from the boiler.

Why is my radiator not getting hot after bleeding? ›

Check your thermostatic radiator valve

A common problem that might stop your radiator from getting hot, even after bleeding, is due to a stuck pin on your thermostatic radiator valve (TRV). You can check if this is the issue yourself by removing the cap/head on your TRV.

Do you need to use gasket sealer on a water pump? ›

You don't need sealer on the pump gasket if you already put the sealer onto the pump. The gasket is good enough on the engine, you don't need to put sealer on that. It's a good idea to put it on the pump. Then it stays in place and doesn't move.

Do I need to empty coolant before refilling? ›

Is It Ok To Add New Coolant Without Draining The Old? There is no problem with just topping up the coolant. You can add the coolant without flushing out the old. However, with time, the older coolant becomes acidic.

Do I have replace the thermostat if I replace the water pump? ›

It is a common practice to also replace the vehicle's thermostat when doing a water pump replacement. It is not always needed, but if you suspect that your engine got hot when the water pump failed, it's a good idea to take care of it.

How do you purge a well water pump? ›

Running the water into a clean bucket helps determine the amount of sediment in the water. When the water stops running, switch the pump on for approximately 30 seconds. Continue the cycle of running the pump and draining the tank until the all of the discharge water remains clear and free from sediment.

What happens if too much water is pumped from a well? ›

If you install a pump that has a greater capacity than the aquifer, groundwater is removed at a faster rate than the aquifer can naturally replenish itself and, over time, “dewatering” occurs. Dewatering is also caused by extended over-pumping. Over-pumping is considered to be the number one cause of well failure.

How long does it take for sediment to settle in a well? ›

It can often take a few weeks for sediment to settle in a newly drilled well. If an old well is starting to deteriorate or deplete it can start to produce sediment as well. Sometimes well pumps will pick up that sediment and bring it to surface.

How long does it take to prime a water pump? ›

Turn the pump's power back on, and allow it to run as-is for about a minute. If you opened valves on your pump, wait until water seeps out from them before closing. Wait for your water pump to finish its cycle. If the pump turns off naturally, you've fully primed your pump.

How do you burp coolant after thermostat replacement? ›

How to Burp the Cooling System
  1. Find the Radiator Cap or the Coolant Reservoir Cap. ...
  2. Replace Any Lost Coolant. ...
  3. Squeeze the Upper Radiator Hose to Remove Any Air Pockets. ...
  4. Look for a Bleeder Screw and Open It If There. ...
  5. Attach a Funnel and Let Air Burp Out of the Cooling System. ...
  6. Raise Coolant Fill Area as High as Possible.
Jun 3, 2022

Should air be purged when replacing a thermostat? ›

A thermostat replacement causes air to enter the system, and getting rid of any remaining air pockets afterwards is extremely important.

What causes an engine to overheat after replacing thermostat? ›

If your car is overheating with a new thermostat, you could be dealing with a clog in your radiator and/or heater core, a bad water pump, a broken radiator, or any number of other coolant-related issues. The first and most important thing is not to drive your car until the issue is resolved.

How do I know if I have air trapped in my cooling system? ›

Signs and symptoms of radiator airlock include: Overheating during normal driving. Heater not functioning correctly. Reduced performance.

Do you need to bleed air out of coolant? ›

You need to bleed the air out of the cooling system in your car. Air pockets—or hot spots—are dangerous. Besides causing little or no heat to come out from the heater, it may cause: Engine overheating.

Do I need to flush coolant when changing thermostat? ›

The cooling system is recommended to be flushed out anytime the thermostat is replaced if the coolant has not been changed or flushed recently.

Why is my car still overheating after changing thermostat and water pump? ›

If your car is still overheating even after you've changed the thermostat, you're likely dealing with an issue with your radiator. It could be clogged, which would restrict the flow of coolant and cause your radiator to overheat.


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