Dodgy Bora Thermostat?

artvandelay48

Hi All,
Another question about my VW Bora. It seems that when driving the dashboard temp gauge shows the temp at halfway for a while and then after about 10-15 minutes (it varies) it goes right down to nothing. Is this indicative of a dodgy thermostat? It couldn't be normal behaviour could it? I have just had the car a couple of monthas and its an 02 1.4l.
Thanks a million...

Neilw

It could be a coolant temp sensor, these are known to be problem, the updated (reliable) part is green in colour whereas the original is black.

Give vw a call they might be able to advise you.

artvandelay48

Cheers Neil, any idea if these are expensive to fix?

DublinDilbert

What are the driving conditions when the gauge drops back to showing a low temperature?
Are you sitting in traffic?
Are you sitting on a motorway at 50mph?

If the Thermostat is faulty ( staying open too long ) you would still expect the car to maintain a reasonable temperature when in traffic. When you hit a motor way you would expect the temperature to drop off.

If the temperature gauge always drops off, no matter what the driving conditions are then i would say you might have a faulty temperature sensor.

When the temperature gauge drops off, does the internal heater temperature in the car also drop off?

crosstownk

Change the temperature sensor before you do anything else - these things regularly give trouble on Golfs/Boras/Polos.

The sensor is mounted in a plastic housing to the right of the engine as you look in - it should have a green plastic ring just below the plug - if it does the part number should be 059 919 501 A.

To replace it just pull out the circlip (lever it gently with a screwdriver if you have to), remove the old sensor, push in the new one and refit the circlip. You should also buy a new seal that fits below the sender (N 903 168 02) and a bottle of G12 coolant.

Don't attempt to do this until the engine is stone cold and release the coolant resevoir cap to release any pressure. Also be sure to have the ignition turned off or you will register a fault in the fault memory once you disconnect the sensor.

artvandelay48

DublinDilbert wrote:

What are the driving conditions when the gauge drops back to showing a low temperature?
Are you sitting in traffic?
Are you sitting on a motorway at 50mph?
When the temperature gauge drops off, does the internal heater temperature in the car also drop off?

I first noticed the gauge dropping off when sitting at a light after the car had been running for 10 mins or so. Since then, it seems to drop off at varying times but usually within 10 - 20 mins of running.

I am not sure about the heater temp as I haven't really been using it in this weather. I hope that helps.

Neilw

artvandelay48 wrote:

Cheers Neil, any idea if these are expensive to fix?

The part is around 24 euro's plus vat, just follow crosstownk's advice above and you should be ok.

WAIT TILL THE ENGINE IS COLD!!

Neil.

crosstownk

Here are the images I couldn't attach to the PM......

In the first image, the switch is item #10
The switch is mounted into the housing listed as #1 in the second image.

Let me know if you're still stuck.

EDIT - you may need to enlarge the images to make out the numbers.

Tea drinker

Yeah, had to get this done on my passat recently, those sensors are junk, even the new green ones... it was a green taken out of mine last year. 03 passat.