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General Information => Troubleshooting => Topic started by: Kneale Brownson on November 10, 2007, 05:27:40 am

Title: coolant level surprise
Post by: Kneale Brownson on November 10, 2007, 05:27:40 am

I was getting the floating thermometer coolant level warning intermittently, so I added some mixed coolant to the reservoir, raising it from just above the "MIN" mark to just above the "MAX" line.  Now that I've been using the heater some, I see the coolant level is almost a half inch above the "MAX" line.  

I presume I had an air bubble or something because of not using the heater.

Title: coolant level surprise
Post by: jtanguay on November 10, 2007, 09:35:35 am

isn't the heater fully connected in the loop? only mk1's have the shut off valve?  just opening the coolant cap and running the motor can help bleed off some of the bubbles.

Title: coolant level surprise
Post by: fatmobile on November 10, 2007, 11:33:14 pm

What kind of car is it and are you getting a steady stream of coolant through the little line coming off the radiator?

Title: coolant level surprise
Post by: Kneale Brownson on November 14, 2007, 02:59:17 pm

It's a 1994 Jetta TD.  

There is a steady stream of coolant into the reservoir from the little hose to near the top of the reservoir.

I haven't seen any change in the level since I noticed it was well above the mark.  I still get an intermittent floating thermometer flash on the instrument cluster.

Title: coolant level surprise
Post by: Doug on November 14, 2007, 03:46:17 pm

The float level sensor sometimes gets crudded up to the point of faulty messages. It is cheap to replace or you could try cleaning it in some soapy water.

Title: coolant level surprise
Post by: insdtanoodles on November 14, 2007, 05:50:11 pm

good luck getting rid of that warning light, mine has been going off forever. I have cleaned the take out 3 times and bought a new one and it's still going off randomly so I just check every now and then to make sure I didn't actually start loosing coolant

Title: coolant level surprise
Post by: fatmobile on November 14, 2007, 11:32:11 pm

I wonder where that sensor is grounded.
 Might be a corroded ground connection.

Title: coolant level surprise
Post by: Kneale Brownson on November 15, 2007, 11:07:52 am

According to Bentley wiring diagrams, the ground for the sensor is in the engine compartment wiring harness.  I suppose that means one of those "welded" connections where they pinch several grounds together with a crimped ferrule and then bury it in the harness.

Title: coolant level surprise
Post by: fatmobile on November 16, 2007, 11:12:43 pm

Check voltage on each side of the sensor,... pull the rubber plug cover back. Should be 0 volts on the ground side.

Title: coolant level surprise
Post by: Kneale Brownson on November 18, 2007, 06:32:57 pm

Or I could look for continuity to a ground source?

So after I determine which is ground, maybe I should run a good, new clean ground to the chassis or the engine?