KC Guy wrote:Just got my car back from the local VW shop. They diagnosed the problem as the temperature gauge that needs to be replaced. They tried the coolant sender unit but that did not resolve the problem. As I understand it: the temperature gauge performs 3 functions? First, the needle shows the water temp. Second, the idiot light comes on steady to advise that the water temp is high and reinforces the temp needle. Third, the idiot light flashes if the coolant level is low. Anyhow......they said that is what needs to be replaced and is no longer available. The part number is: 155919511B. I'm also in need of a glove box lid (black). The hinges are broken on mine. Thanks!!
If the Coolant Gauge works, that is never goes to 0 as you are driving, then it isn't the issue.
The Coolant Gauge is a works or fails kind of thing. And I have a DIY on it here.
Now if they said, that your cluster has a issue, then I would suspect that the instrument cluster may have a bad ground, or a bad that needs plumping up, but it isn't your gauge.
There is no way that the "coolant sender unit " was the issue, if the car registers fine and it is just a blinky light, then you have a issue with the coolant level sender.
That is the piece that is in the middle of the res.
Unclip the connector from the res.
Use a pair of Channel Locks to grab the nut and loosen it to remove it.
Once you have it out of the jug, you will see 2 metal prongs. The prongs get corroded and scaley and need to be cleaned so they have the proper resistance to the
fluid.
But here is a test.
With the Car off.
Remove the Black connector off the grille side of the engine.
Jumper a 9V dc Battery to the connector. Negative to the Brown, Positive to the other.
Go look at your water temp gauge, it should be 3/4 to full deflected, and leave the battery there for about 3 minutes, if it goes to 0, or doesn't deflect the gauge is bad.
Now if the coolant sender (black one you disconnected) is bad, then the 9V shouldn't turn on the blinky blinky light during the test. If it does then you have a ground issue with the cluster usually.
If you then take the level sensor probe out of the res (when cool) and clean the tips, Make sure that the res has a/f or water in the hole to cover the probes half way if not, then increase the amount of fluid in the res.
If the car isn't running hot, then the issue is either with the Probes being open, your a/f to water isn't 50/50, or your Coolant level sensor control unit is bad, and tha tis located in the fuse panel number 42.
see: cabby-info.com
But in 30 years of wrenching I have never seen one of these things go bad.
To test the level sender, using a ohm meter on smallest scale, touching the meter to the connectors you will have infinity.
Short out the metal tips, and remeasure, you should have 0 ohms, if you have 200Ohms or greater then the probe is bad.
It could also be a broken wire from the probe connector in to the fuse panel.
If you do not have a Res Jug that has a connector right in the middle of it, then some one installed the wrong jug, and you don't have a sender, as they made three different mk1 jugs
that I have seen over the last 30 years.
Yours should look like:
If yours looks like this it is the wrong one as it is missing the hole for hte level sensor, and the connector is probably dangling behind the strut tower.
), please post a picture of your car. We all would love to see it.
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