On the 124 chassis cars how do you perform a check on the coolant level sensor to see if it is defective?

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Den
1993 MB 300D 2.5
2001 VW Jetta TDI 5 spd.
2001 new bug TDI 5 spd.
Motorcycles

Is the sensor triggering the warning light even you have enough coolant? or no warning light and not enough coolant at the reserve tank?

amt

If the light is on and the overflow tank is full, the sensor is defective. If you're trying to see if the light will come on, siphon (with a turkey baster) coolant out of the overflow tank and when you get below the sensor the light should come on. The sensor is only about $12 to $15 - if it's all corroded it's probably better to just replace it.

Coolant tank is full, light on, must be a bad sensor. There should be no other reason for the light to be on, right?
Tanks

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Den
1993 MB 300D 2.5
2001 VW Jetta TDI 5 spd.
2001 new bug TDI 5 spd.
Motorcycles

I seem to remember reading that on some model the coolant sensor works in conjunction with the washer resevoir sensor. Check the washer level too, just to be safe. I wish I could remember where I read that.

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Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

i had the exact problem on my car.

it turned out to be dirty coolant level connectors and sensor connections.

it was a cheap fix after i cleaned the electrical connections without having to replace any parts ,so this should be your first check.

The low level warning light of my car turns on even with a full tank of coolant.

Please advise if i just pull out the sensor/plug from the bottom of the tank.

Thank you and have a good weekend.

92 300E
147,836 KM

As previous post indicated, sometimes the problem is just a dirty, corroded connector in which case you don't need to pull the sensor, just clean up the plug. If the connector is corroded and original it may break apart when you take it off. A replacement electrical connector is available from the dealer for a couple of dollors. It's claimshelll design - you just open it up to take the wires out and then put the wires back into the new one.

Of course the problem could be the sensor in which case you have to remove and replace. This requires siphoning (with a siphon pump or turkey baster) the tank to a level below the sensor. There is another method of detaching the tank and turning it on its side, sensor up, but siphoning seems to me easier. Then you have to remove a little clip and pull the sensor out. The sensor itself is only $12 to $15 so if you go to all this trouble you might as well put a new one in. It comes with new o-rings which are less likely to leak.