2000 S80 Engine Coolant Level Low Warning.

[christophervolvos80]

I have been getting this warning that is going on for a month now and I can't figure out what exactly is causing it. The coolant level is visible and full. I have so far replaced the Coolant Level Sensor ($40) and the Coolant Expansion Tank ($65) using all OEM. This has not fixed the problem the warning still shows on the dash. On top of this my engine temperature sensor is failing too (I think). It remains at 0 or Cold and will shoot up to normal after a few minutes of driving then it will drop again and repeat over time. I replaced the engine thermostat and the problem with the engine temp still continues. I have ordered the the engine temp sensor as the next possible thing that is causing this. IF this works GREAT, if NOT then what would be my next guess on the list of trouble shooting? Or should I go to my Volvo Master Mechanic again? Is the warning with the coolant level low related to my faulty engine temp readings?

[oragex]

Of course, the coolant temp sensor is a wise move, it seems it's not working properly.

I'm also thinking at an air bubble trapped inside the coolant. Was the new thermostat placed with the burp valve at the most upwards position? Was the temp gauge doing the yoyo with the old thermostat as well?

I might be wrong, but to me the coolant level warning is only triggered by the level sensor at the bottom of the reservoir. Others will correct me. But if it's true, then I would check the float inside the reservoir. It might have simply got stuck, just gently tap on top of it with a pen to see if it's rising again. The level sensor at the bottom fails often times when the reservoir is pulled upwards from it's position without disconnecting the sensor's electrical plug that's located just nearby. The wire to the sensor is very fragile and gets pulled at this moment.

[abdomar528]

Hi All,

Watch this video I made. I have the exact same issue with Volvo original parts. There must be a bad batch of Volvo coolant tanks.

I compared two new tanks and saw that the first new one I bought was bad. Watch the vid here where I test it by placing the tank up side down to trick the car into thinking that the coolant level is full. The bad one being upside down still shows the level is low while the new one is not showing the level is low.

[majorcode]

christophervolvos80 - Hope you have solved your issue but in my opinion few things should always considerd while working with electronics of the car and replacing coolant. Always reset ECM in case you unplugged or plugged some thing (Though many disagree with me but it always worked for me to give a fresh start up test), secondly replacing coolant might seems fairly easy task but it has some very narrow points to be noted while working like what is the quality of your new coolant specially when dealing European car, checking air bubbles in the expansion coolant tank, let the car idle for at least 10-15 mins and have little drive after changing coolant. These cars always demand high expenditure when not diagnostic properly.

Omar, Jahangir here, your video is great and knowledge able but I never suggest "Jugadr" or the way you blocked the hole (I did once but it surly never recommended). Which OEM Brand you got other than genuine ? 2ndly does putting aluminum on upper hose works?

[jenkinskg]

test sensor with magnet

[masy304]

Of course, the coolant temp sensor is a wise move, it seems it's not working properly.
I'm also thinking at an air bubble trapped cdg Airport transfer inside the coolant. Was the new thermostat placed with the burp valve at the most upwards position? Was the temp gauge doing the yoyo with the old thermostat as well?

Hello,
I agree with the trapped air bubble. This is probably the cause. Otherwise I do not see what else!

[Cees Klumper]

AFAIK the coolant low level sensor in the tank is the only switch that can make the light come on. So if the tank is full, airbubbles somehwere else in the system should not trigger the light.