The model i have is a DWC2838LS. the thermostat keeps showing E4 for the bottom level. as a result the top temperature starts to rise. i've been having to unplug and replug the unit MANY times. which seems pointless now b/c the issues keeps happening. VERY frustrating. any advice on what's wrong?

Do you mean the engine is overheating?
Few modern engines will tolerate overheating without sustaining damage and often one incidence of overheating is enough...

Localised overheating often causes cracks in castings and always causes distortion of metal.

While it is possible the temperature sensor is faulty and sending incorrect temperature information to the computer that drives the gauge, there are conditions where a healthy sensor can send low temperature messages about an engine that is overheating.

To be accurate the sensor must be immersed in coolant so a low coolant level can result in a low reading and similarly a failing head gasket will cause gas bubbles in the cooling system that will rise to the top of the engine, displace coolant, interfere with the thermostat operation and overwhelm the degassing circuit.

It is important you get the problem diagnosed and sorted.

Thermostat could stack in close position, radiator plug up.

Could be that the thermostat has packed up...

Check all your coolant levels are correct and then take her for a good run out....keep your eyes on the temperature gauge,,if your temp gauge hardly moves then your thermostat is at fault....replace it.

If temp gauge works fine, you may be airlocked in your heater matrix... Try setting heater to full heat with fan on full power,, whilst car is ticking over, remove radiator / expansion bottle cap carefully and start squeezing your coolant pipes. This should force any air out through your rad/bottle top..

Please be aware that as your temperature rises in the engine. Your coolant will expand and start to flow out of the rad/expansion bottle..at this stage quickly replace the cap....check your heater...leave engine to cool....unscrew rad/bottle cap, check coolant levels, top up if necessary and squeeze pipes again..start car with heater/fan on full and repeat above.....

Hope this helps..

This sounds as if you have air in the system, you will need to bleed it. Take the radiator cap or coolant expansion cap off, with engine turned off, Now squeeze the bottom hose, and the top hose continually until you see bubbles appear ,the coolant level should momentarily rise and then fall when you release the hose, do this to all the hoses ie, heater hoses as well as the top and bottom hoses, keep doing this until no bubbles appear, by this time the coolant level should have dropped,then start the engine and run at tickover until the coolant level stabilizes,turn off engine and top up coolant to the level,refit cap and run to operating temperature. If this does'nt cure the problem the chances are that the system is drawing in air , but thats another problem! hope that helps

You have a water leak from the sound of it or water is draining from over heating. Things to check for, leaks at the hose connections, leaks at heater connections on engine, leaks at water pump and any leaks at head gasket. Assuming there are no leaks check or replace or adjust your water pump belt. Take the thermostat out and run the engine without out it. If the problem is solved replace the thermostat recommended for you car. You can also have it checked as well.

REPLACE THERMOSTAT IF TOP COOLANT COOLANT HOSE GOING TO RADIATOR IS HOT TO TOUCH THERMOSTAT OPEN. TO BLEED COOLANT SYSTEM FIRST YOU NEED TO ADD COOLANT TO THE COOLANT OVER FLOW JUG UNTIL COOLANT LEVEL STOP DROPPING AND STAY AT FULL COLD MARK.WAIT 3 MINUTES IF COOLANT DROPS ADD MORE COOLANT UNTIL COOLANT STAY AT FULL COLD MARK.WITH RADIATOR OVER CAP OFF CRANK ENGINE FOR MINUTE WATCH COOLANT LEVEL AT OVERFLOW JUG.IF COOLANT DROPS ADD MORE COOLANT IN THE OVERFLOW JUG.WHEN COOLANT LEVEL STOP DROPPING IN OVERFLOW JUG.SCREW BACK ON THE RADIATOR CAP TO OVERFLOW JUG.WHILE ENGINE IDLING WATCH TEMPERATURE GAUGE WHEN TEMPERATURE START CLIMBING TURN OFF ENGINE WAIT A WHILE KEEP FROM GETTING SCALDED.WHEN COOLANT COOL DOWN SOME. PLACE A LARGE RAG OVER THE COOLANT OVERFLOW JUG OPEN CAP LITTLE AT A TIME UNTIL PRESSURE RELEASED, THEN REMOVE CAP ADD MORE COOLANT IN THE OVERFLOW JUG TO THE FULL COLD MARK.THEN REPEAT THE PROCESS SCREW BACK ON THE COOLANT OVERFLOW RADIATOR PRESSURE CAP.THEN START ENGINE WATCH TEMPERATURE GAUGE WATCH COOLANT TEMPERATURE GAUGE WHEN COOLANT TEMPERATURE START RISING TURN OFF ENGINE AGAIN WAIT UNTIL ENGINE COOL DOWN ENOUGH TO KEEP FROM GETTING SCALDED TAKE PLACE LARGE RAG OVER RADIATOR CAP WHICH IS THE COOLANT OVERFLOW JUG CAP OPEN CAP LITTLE AT A TIME UNTIL PRESSURE RELEASED ADD COOLANT UNTIL AT FULL COLD MARK. WHEN YOUR COOLANT LEVEL STOP DROPPING.AND TOP RADIATOR HOSE VERY HOT THERMOSTAT OPEN AND AIR IS OUT THE COOLANT SYSTEM. MAKE SURE YOUR COOLANT OVERFLOW JUG HAS COOLANT IN IT,WHEN ENGINE COOL DOWN CHECK COOLANT OVERFLOW JUG KEEP COOLANT LEVEL AT FULL COLD MARK.BECAUSE IF OVERFLOW JUG IS EMPTY THATS A SIGN RADIATOR COOLANT LEVEL LOW.WHEN OVERFLOW JUG EMPTY IT WILL ALLOW AIR GET IN THE COOLANT SYSTEM AND CAUSE CAR TO OVERHEAT.WHEN REPLACING THERMOSTAT ALSO REPLACE THE RADIATOR CAP ON THE COOLANT OVERFLOW JUG.

You've got air trapped in the cooling system.The lowering and rising is caused by the water pump sucking the coolant into the engine thru the bottom radiator hose when the thermostat is closed. When you let off the throttle, the water pump slows down, an since the thermostat is closed, the coolant has nowhere to go except back into the radiator.You need to bleed the air from the cooling system or it can cause over heating and the heater may not work right. Here's how to go about it: You'lll need a gallon of antifreeze. Use a jack to raise the front of the vehicle so the radiator is higher than the engine. Remove the radiator cap and start the engine. Make sure the heater controls are on the hottest setting, but do not turn the heater on. Let the engine warm up to normal temperature. Watch the coolant level in the radiator. When the thermostat opens, the coolant level will drop. Now, add antifreeze to fill it back up. If there is still air in the system, the level will drop again. Add more antifreeze. Continue to do this until the coolant level stabilizes. Put the radiator cap back on and make sure the temperature Gage doesn't show overheating. Turn on the heater to make sure it blows hot air. Your done

this sounds like a possible restriction in the radiator itself. Start by checking the radiator hoses by, after it is warmed up, feeling the top and bottom hose for temperature change. The top should be hot being that it gets it water from the engine and then the bottom should be cooler than the top. If the bottom is cold, you have a restriction in the radiator. If the top hose is cold, than the thermostat is stuck. It is also possible to have a waterpump which is coming apart inside and not circulating water to cool. Try a good chemical flush and follow the instructions on the bottle and see if it helps. Let me know what you find and than we can move forward.

Hi Code P 0217 does point to the thermostat but it also points to the wiring, cooling system, and the temperature sensor, to check the thermostat start engine then once the temperature gauge in the car reaches normal the thermostat should open and the top hose that goes into the radiator will warm up quickly as the thermostat opens, if the thermostat is stuck in it's open position the top hose will start warming up before the engine reaches it's working temperature, hopefully i have explained it clearly,

replace thermostat.feel top radiator hose and bottom radiator hose if they both should be hot 10-15 minutes.if not replace thermostat.