ONGOING COOLANT LEAK

Check the hose going to the expansion tank, That it is not pluged up.

FILL COOLANT SYSTEM UP BY POURING COOLANT IN THE EXPANSION TANK UNTIL COOLANT LEVEL STOP DROPPING IN THE EXPANSION.WHEN YOU POUR COOLANT IN EXPANSION TANK AIR BLEED OFF THROUGH THE SMALL COOLANT LINES GOING TO EXPANSION TANK.WITH PRESSURE CAP OFF RADIATOR COOLANT LEVEL IN EXPANSION IS AT FULL COLD MARK.WHAT YOU TO DO CRANK ENGINE UP LET IDLE WARM UP UNTIL COOLANT DROPS IN EXPANSION TANK KEEP ADDING COOLANT UNTIL STOP DROPPING STAY AT FULL COLD MARK.WHEN COOLANT LEVEL START RISING IN EXPANSION TANK.PUT PRESSURE CAP BACK ON RADIATOR.WHILE ENGINE IDLING WATCH TEMPERATURE GAUGE.IF START CLIMBING TURN OFF ENGINE LET IT SIT FOR LITTLE WHILE TAKE A LARGE RAG OPEN RADIATOR PRESSURE CAP A LITTLE AT A TIME TO KEEP FROM GETTING SCALDING TO RELEASE AIR IN COOLANT SYSTEM.WHEN PRESSURE IS RELEASED OPEN PRESSURE CAP ADD MORE COOLANT IN THE EXPANSION TANK.CRANK ENGINE AGAIN LET IDLE WHEN TEMPERATURE GAUGE START CLIMBING. TURN OFF ENGINE WAIT FOR WHILE BEFORE OPEN RADIATOR PRESSURE CAP.WHEN YOUR THERMOSTAT OPENS WHEN TOP RADIATOR HOSE IS HOT AND ENGINE COOLANT TEMPERATURE GAUGE STOP CLIMBING AND COOLANT LEVEL STOP DROPPING IN THE EXPANSION TANK.ALL AIR IS EXPELLED FROM COOLANT SYSTEM TO KEEP ENGINE FROM OVERHEATING.

Inside your car's engine, thousands of controlled explosions called combustion events occur. These explosions are created by igniting a fuel / air mixture inside the engine. Spark plugs are used to ignite the fuel / air mixture contained in the cylinders. These explosions are converted into power through the engine while producing a large amount of heat. These high temperatures are controlled with the help of the cooling system. A cooling system consists of a water pump, cooling fan, thermostat, radiator hose, hose clamps, radiator, radiator cap and coolant. Engine coolant is used to transfer heat from the engine to the radiator by the cooling system. The radiator removes heat from the coolant by forcing air through the radiator cooling fins. Without coolant your engine will overheat and if left unattended severe engine damage will occur. Engine coolant colors can vary from green, orange, blue, clear and yellow each having their own unique protective and environmental properties. Coolant leaks are a common car problem that can lead to overheating; we have listed some of the most common causes below.(Always inspect engine cold to avoid personal injury) (note: coolant and antifreeze refer to the same product, in below freezing, coolant lowers the freeze point hence the name anti-freeze and in warm weather coolant help raise the boiling point, "coolant").
Troubleshooting Procedure
Step 1: Check Engine Coolant Level, Test For Leaks - Engine coolant is used to transfer heat from the engine to the radiator; if a coolant leak is present the engine will eventually overheat. Inspect the engine coolant level in the coolant reservoir tank; coolant level should be between the hot and cold marks. Always check the coolant level when the engine is cold, preferably over night. If the coolant level is not between the reservoir marks the cooling system may have a leak.

If engine overheating has occurred the coolant level will naturally be low due to expansion of the coolant from the extreme heat of the engine. This heat expansion forces coolant out of the radiator and coolant reservoir. To test for an engine coolant leak move the car to a dry smooth surface and allow the engine to cool. Remove the radiator cap and carefully (do not spill) add water until full, then re-install cap. Start engine and allow to run for about three to five minutes (do not allow to overheat) while the engine is running inspect the ground below the engine, if an engine coolant leak is present observe the location of the coolant drops, this will help determine where to start looking for the coolant leak (shut the engine off before inspecting).

If no coolant is observed two additional checks are needed for a complete test. With the engine off remove the engine oil fill cap and turn it over, if a milky oil condensation is present the engine may have a failed cylinder head or intake manifold gasket allowing coolant to leak internally. To inspect engine gaskets disassembly is required. Next, the car heater core must be inspected; the quickest way to check the heater core condition without removal the heater core is to inspect the passenger's side foot well compartment carpet for the presences of coolant. If coolant is present the heater core has failed and must be replaced or repaired. After necessary repairs have been made refill the cooling system with manufacturers recommended engine coolant and recheck operation.

Hi!!
On the bottom of the radiator, there is a drain valve, just open it and drain fluid into a container, if you want faster drain, remove bottom radiator hose.
NOTE: DO NOT OPEN SYSTEM WHEN HOT, COOLANT IS POISONOUS FOR PETS, KEEP IT AWAY FROM THEM.
Good Luck!! Rate this post!!

Is it the LOW coolant light? Your car is equipped with a sensor on the expansion tank (radiator overflow). Right front fender. It's there for when the car heats up. As the engine heats up and the coolant expands it racks into the reservoir/overflow/expansion tank. When the engine cools, it sucks the coolant back in. If your car was low on coolant then there's a good possibility that as it cooled, it sucked the recently added fluid in. Check that it is full to the "cold full" level by looking at the tank before you start it for the day. If it's not, then the sensor is telling you to add coolant. If it is, then the sensor in the tank may be bad.

There could be a couple of reasons for this,

1. The thermostat could be stuck closed creating more pressure than normal. Your temp guage would show a higher temperature or you have another blockage in the system.
2. The expansion tank is too full.
3. The cylinder head may be leaking. If you fill the system run the engine to normal temperature with the radiator cap off, look for quite large bubbles coming out of the filler cap. If the head is badly leaking, they can be like a volcano. The temp will rise quickly from cold and the engine will overheat in a short distance.
It does seem odd that it would only spill over after 20 mins. Suspect that the expansion is over full first if your temp is normal. Let it run until it stops and see where the level is when the engine is cold.

We have had some similar problems with some BMW's,the last one we replaced the expansion tank.Before we attached the upper radiator hose to the radiator we filled the engine with antifreeze through the hose.Install the hose and fill your expansion tank to the proper level and run the engine to operating temperature.

Your engine is constantly warming and cooling. Your radiator cap has a set pressure release. As the pressure builds it allows coolant to flow out of the radiator into the makeup tank. As the engine cools it sucks coolant out of the makeup tank back into the radiator. If it overheats a lot then the makeup tank will overflow out of the overflow tube and it usually drips out under the car. If your radiator cap is bad or weak it can let coolant out when it shouldn't. This isn't a frequent problem but it can be a cause. The most likely cause is your thermostat is bad. The thermostat is closed when you start your engine and keeps the coolant inside of the block so it can't circulate through the radiator and cool until your engine is warmed up then at a set temperature (depending on thermostat), usually 195 degrees it starts to open and allow the coolant to circulate and cool. The thermostats can get bad and stick partial open or all the way closed and open. Yours is probably not functioning right and causing your makeup tank to overflow. When engine is cool look at makeup tank and you will see a minimum and maximum mark. Fill to maximum with coolant then start the car and let it warm up and monitor the coolant level and see if it is overflowing.

The water (coolant) in the expansion tank will rise and fall with the engine temperature. What the expansion tank does is collect and return coolant to and from the engine. When the engine warms up the coolant gets hot, builds up pressure and opens up the radiator cap. The coolant then goes into the expansion tank. Now when the engine cools down the pressure drops in the cooling system and the pressure drop (vacuum) pulls the coolant back into the engine via the radiator cap. The radiator cap allows the cooling system to build up pressure and by doing so increases the boiling point of the coolant, but when that pressure exceeds the caps rating the cap opens and the coolant goes to the expansion valve. The cap has another part to it that when the engine cools down and a partial vacuum is created in the cooling system a "valve" in the radiator cap opens and allows the coolant to be drawn back into the engine. I would look at your radiator cap to see if any gunk or build up is on it, and check the rubber gaskets for cracks. It's easiest just to replace the cap because they are inexpensive and easy to replace (2-10 dollars). The expansion tank should have two hoses on it. The one on the bottom comes from the radiator and the one on the top (possibly part of filler cap) runs down and is open to the ground. That way if it is overfilled or becomes overfilled it will slowly leak onto the ground. When and if you change your radiator cap, make sure the engine is cooled down, remove cap and start engine and turn heater to full blast, full heat. Leave the cap off and let it run until engine warmed up. This should burp out any air pockets that may have happened when coolant was changed. Also top off the coolant in the radiator while it is running. Hope this helps and good luck

There's many causes of overheating (on all cars..).
The first and most obvious thing I would do after checking the coolant level in the radiator expansion tank was at the maximum level, would be to check for coolant leaks while the engine is running with a 'few revs' on a warm engine.

Hoses can split internally and also become soft and collapse internally through age. When this happens the hose becomes blocked and prevents the coolant from passing through easily. If a hose feels 'soggy'/soft and is easily squeezed flat by hand, it's suspect.

Coolant can also leak from the heater hoses, the heater unit, the bearings/seal on the water pump and of course the radiator. Nor is it always easy to see a leak let alone find it. If the in-car heater unit is leaking the carpets may be wet at times and sometimes, the windows may mist up when the car is standing - this is the coolant condensing on the interior of the glass.

Ok... you can't see any leaks while the engine is running. Is the car losing coolant when it stands? Or is it losing coolant when the engine is running? ( a split hose may only leak when it is pressurised with warm coolant) Or is it just losing coolant when it overheats?

Remove the cap from the radiator expansion tank when the engine is cold. Make sure that the water level is at maximum. Leave the expansion tank cap off. Leave the car standing overnight and next morning look at the coolant level. If it has dropped there's probably an unidentified leak somewhere. If the coolant level hasn't dropped, it points towards a problem that is caused when the engine runs.

With the expansion tank cap still off (get a flashlight to help you) start the engine and peek into the expansion tank. Watch what happens to the coolant (though do keep your face out of harm's way). As the coolant begins to circulate air bubbles will probably appear within the coolant. This is quite normal - air is 'bleeding out' of the coolant as it circulates. The air bubbles should stop after a couple of minutes.

As the coolant warms it will rise up in the expansion tank (keep your face out of the way ..). If the air bubbles continually appear or, there's a constant and continual stream of bubbles or a 'violent bubbling' then this may point to problems with a warped/cracked cylinder head or leaking head gasket (or both).

A defective cylinder head/gasket can allow exhaust gasses to be pumped into the water jacket (the coolant system) simply by the compression action of the pistons. Just like a hypodermic needle can inject air into your bloodstream. When this happens - pressurised exhaust gasses being forced into the cooling system - the cooling system itself becomes pressurised.

The coolant itself can find its way into the cylinders where it is vapourized and pumped out of the exhaust along with the exhaust gases. If you can't find any leaks - the missing coolant may be going out of the exhaust as steam (though you may not see any steam as such). A classic sign of cylinder head/gasket problems is overheating. Check your oil - if there's a yellowish/creamy mayonnaise/sludge that's another sign of head problems. The sludge is caused by coolant finding its way into the oil.

No leaks, no bubbling expansion tank - and if you're happy that there isn't a head/gasket problem, turn your attention to the radiator, thermostat and water pump.

With age, cooling fins on the radiator can corrode and crumble away, reducing its cooling ability. Whilst coolant still passes through the radiator it isn't being cooled sufficiently. Check the condition of your radiator. Radiators can also suffer from an internal blockage. With a warm engine that is switched OFF, feel the top radiator hose - it will be hot. Then feel the bottom radiator hose. If the bottom hose is cold it indicates that coolant is not finding its way down/being circulated maybe due to a radiator blockage or failed thermostat. Flushing may cure blockages.

A thermostat can fail in the 'closed' position. When this happens coolant is prevented from getting into the radiator via the top hose. The coolant in the block then overheats causing the temperature gauge to hit red. The thermostat is located (usually - it depends on make/model variations) on the cylinder head where the top radiator hose joins. They're very easy and cheap to replace.

The water pump can leak water when the bearings/seal fail. Coolant that slowly drips onto a warm engine soon evaporates making detection difficult. Way back, some water pumps had plastic impellers (perhaps they still do). The plastic vanes on the impellers used to wear away with age and use, leaving a spindle spinning uselessly in the coolant - not pumping it. Think of an airplane with a propeller. If the propeller blades wore away the 'nose cone' would just spin uselessly and no air would get moved ..

Before jumping to any conclusions and replacing parts unnecessarily, get a workshop to look at the car. A workshop will be able to test the coolant for exhaust contaminants within minutes (or pressure test the coolant system. If there's contaminants present - there's a head problem. No contaminants present - the fault lies elsewhere.

Back to the cylinder head:
It's a 2-3 day job to do the work yourself. A cylinder head must be skimmed prior to refitting. Refitting an unskimmed cylinder head back onto an engine cures nothing.

Years ago, here in the UK, there was a liquid additive called 'head weld' (and one for the radiator called 'radweld') which provided a TEMPORARY get-you-home fix. Head-weld was a liquid added to the coolant system. It contained fine particles in suspension ... these particles were carried to the crack/leak in the cylinder head and formed a 'dam' that was held in place by the water pressure until they (the particles) hardened.

Recently I noticed an advert for a product called 'steelseal' - here in the UK. The advertising blurb claims that it uses new technology without particles to form a permanent fix for cylinder heads/gaskets. It's a clear liquid that you just pour into the cooling system and then run the engine until its fixed. I've never tried it. At around 45 dollars a bottle it isn't cheap, though if it does what is claimed then it's a hell of a lot cheaper than having a cylinder head/gasket fixed. No doubt there are similar products on the shelves of car accessory and parts shops near you.