Can You Change A Thermostat Without Draining The Coolant

Dan Ferrell writes about do-it-yourself car maintenance and repair. He has certifications in automation and control technology.

Failing to bleed air from the cooling system can lead to engine overheat. — Failing to drain air from the cooling arrangement can lead to engine overheat.

Photo courtesy of Michael Sheehan on Flickr

You tin change the coolant in your own garage without leaving behind air pockets—a mutual problem in many modern vehicles that leads to the engine overheating.

As the protective qualities of antifreeze degrade over time, acid content increases and rust spreads out. Soon afterwards, corrosion begins to destroy your water pump, radiator, and surfaces throughout the engine.

That'due south why car manufacturers propose a two- or four-twelvemonth service interval or more than, depending on your particular vehicle make and model and the type of antifreeze your vehicle needs.

And then the sooner you modify that former coolant in your car, the improve. Yous'll but need a few common tools.

And you can piece of work on this automobile maintenance projection on a Saturday forenoon with the help of this guide and without fearfulness that your engine will overheat subsequently.

Just follow these steps.

Annotation: The following procedures don't apply to hybrid vehicles.


Index
I. How to Drain Coolant
II. Refilling the Radiator With Coolant
III. Extending the Service Life of Your Car's Cooling Organisation

Replace the coolant on time to avoid sediment and corrosion in the cooling system.

Photo courtesy of Chris Bede on Flickr

I. How to Drain Coolant

Before you offset, find a well-ventilated expanse with a level surface—if you need to raise your car—and with enough room around your car to comfortably change the coolant.

Wait for the engine to absurd before removing the radiator cap--or the reservoir cap if there'southward no radiator cap. This will prevent hot coolant from gushing out and called-for your skin.
Observe the petcock towards the lesser of one of the radiator tanks. On some vehicles, you need to enhance the front of the car to gain access to the petcock from underneath. If this is so, utilize a floor jack to raise the front of your car and secure information technology with a jack stand. Besides, chock the rear wheels and set the parking restriction.
Place a drain pan under the motorcar toward the radiator drain valve.
Loosen the petcock with your mitt or a pair of pliers or a wrench.

Some radiator drain valves take then little room around them you can hardly reach them with your hand or tool; others tend to rust over fourth dimension, so you don't desire to remove them for fright of causing some impairment. If the drain valve on your car is hard to reach or is rusted, effort removing the lower radiator hose instead to prevent an expensive repair. To exercise this:
- Loosen the clamp holding the hose at either terminate, whichever is more accessible to you—depending on the type of clamp, y'all'll demand a screwdriver or a pair of pliers for this.
- Then, after removing the clamp, break the hose grip at the fitting using a pair of slip-articulation pliers past carefully twisting the hose just a few degrees.
- Once y'all break the grip, manually twist the hose back and along every bit y'all pull it off its plumbing equipment. Let the old coolant drain into the drain pan.

v. Now, remove the coolant reservoir, empty the coolant into the drain pan. Flush the reservoir and reinstall it.

6. Loosen the radiator cap and wait for the coolant to drain completely. Draining the radiator and overflow reservoir ordinarily removes about 50% to 70% of the coolant in the system.

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2. Refilling the Radiator With Coolant

With the coolant removed and the radiator and reservoir cleaned, information technology's time to refill the cooling organization. Before you start, though, cheque and run across if your system has a purge valve (aka bleeder screw). This is a small, single screw, usually located on the thermostat housing, which connects to the upper radiator hose on the engine side. Check your machine owner's transmission or vehicle repair transmission.

If you lot don't have the vehicle repair transmission, you lot tin get an inexpensive copy for your item vehicle brand and model through Amazon. This Haynes manual, for example, comes with procedures for many maintenance, repair, and troubleshooting tasks you can do at dwelling house. And so the transmission pays for itself pretty presently.


Cooling System Bleed Methods	Application
Bleed screw	Depends on car model
Jack stand	Works on most models
Funnel method	Works on most models
No bleeding	Many pre-1995 models don't need bleeding

These are iii mutual air purging methods you can use in your vehicle:

Purge Valve Method

Before you start, cheque and see if your system has a purge valve (aka bleeder screw). This is a small, single screw, commonly located on the thermostat housing, which connects to the upper radiator hose on the engine side. Check your car owner's transmission or vehicle repair transmission.

The purge valve volition miscarry any air that gets into the arrangement after adding the new coolant. This will forestall the formation of air bubbles or hot pockets inside the engine that crusade overheating.

Jack Stand Method

Another style to purge air from the system is to apply what I call the jack stand method. All you have to do is raise the front of your car to position the radiator cervix (fill point) at a higher level than the heater cadre — this is the small, radiator-like component (usually located underneath the dashboard on the rider side) that provides warm air to the vehicle interior. This will prevent the coolant from trapping air bubbling. If you exercise this, secure the forepart of the vehicle with a couple of jack stands, block the rear wheels with wooden blocks, and appoint the parking brake.

Special Funnel Method

Besides, a highly recommended method is the use of a special funnel that makes it easier to fill the radiator or cooling system without introducing air into the system. Check the Amazon advertizement beneath and the video then that y'all have an idea of how information technology works. Follow the instructions that come with the funnel, if yous decide to become one.

Use the most convenient method for you lot, but make sure to purge the air from the organization; otherwise, air bubbling volition prevent proper coolant flow, cause engine overheat, and, possibly, severe engine damage.

Spill-free Funnel

Once you are prepare to make full the system with coolant, follow these steps:

Set the heater temperature control to the maximum.
Slowly add together a 50/fifty mixture of distilled water and antifreeze to the radiator until it reaches the bottom of the radiator neck.

Notation: If you live in an area with extreme climate atmospheric condition, you'll need to increment the amount of antifreeze to the mix. Likewise, some automobile manufacturers recommend using a premixed coolant to add to the system, while others recommend a specific type of antifreeze that you need to mix with distilled h2o earlier adding it to the cooling arrangement. Check your car possessor'south transmission or vehicle repair manual for the right premixed-coolant or antifreeze you lot need for your specific motorcar model.
Fill the reservoir with fresh coolant up to the Low mark.
Install the radiator cap to the first lock position. Start the engine.
Let the engine idle--for well-nigh 15 or xx minutes--until information technology reaches operating temperature. At this bespeak, the thermostat will open up; air volition escape through the radiator cap.

If you're purging the air through a bleed screw, follow these steps:
- Make sure the engine is warm, and the heater is fix to Max.
- Without starting the engine, connect a clear hose to the spiral and place the other end of the hose into the catch pan.
- Scissure the screw open using a wrench and get-go refilling the organization with coolant.
- Let coolant flow through the valve until you see coolant flowing costless of air bubbling. Then tighten the spiral.
NOTE: On some models, the valve bleeding procedure will differ from the one described hither. Check your car possessor's manual or vehicle repair manual for specific instructions for your auto make and model.
Turn off the engine and permit information technology cool.
Top off the coolant in the radiator to the correct level--usually nearly an inch beneath the bottom of the radiator cervix. Then, squeeze the upper radiator hose to expel the air and add more coolant if necessary.
Replace the radiator cap. Brand sure it's fully locked.
Add more coolant to the reservoir up to the Low mark, if necessary.
Supersede the radiator cap.
First the engine again and permit it achieve operating temperature and check for leaks.

Refill the radiator and reservoir with fresh coolant.

Photograph courtesy of bandita on Flickr

Iii. Extending the Service Life of Your Car'due south Cooling Organisation

When you demand to change the coolant in your auto, don't forget the most disquisitional part, bleeding the cooling system, specially on car models with depression-contour radiators. Trapped air will seriously disrupt the system and may cause plush damage.

By replacing the coolant at the manufacturer'southward recommended service interval, you are removing dirt and rust particles that eventually corrode, block radiator and heater small passages, and cause serious system damage. And so follow this guide every fourth dimension yous demand to service the cooling system.

This article is accurate and truthful to the all-time of the author's noesis. Content is for advisory or entertainment purposes only and does non substitute for personal counsel or professional person communication in concern, financial, legal, or technical matters.