Coolant Level Low - New Coolant Tank and Sensor

[Sharkey R]

Ok guys I have a slight issue with the R. Since changing the Coolant Expansion Tank from a brown stained tank to a brand new tank I've had a coolant low warning light on the dashboard. It was decided that the sensor might have been damaged when removing from the old tank and refitting in the new tank so that was changed. Still got the same message on the dashboard. Jamie at PFS was kind enough to send me out another tank as we figured that it might have been a faulty float. Just changed the tank again and I've still got the same warning. Out of curiosity I tried pushing the float down and this briefly turned the light off but then a few seconds later it comes back on.

Any ideas?

[jamesy12345]

Genuine or aftermarket tank? Wiring OK?

[Sharkey R]

Genuine or aftermarket tank? Wiring OK?

Aftermarket tank, tried 2 tanks and both do the same thing. Yeah the wiring seems fine. It's all clean and there's no kinks or anything in it.

[jamesy12345]

Aftermarket tank, tried 2 tanks and both do the same thing. Yeah the wiring seems fine. It's all clean and there's no kinks or anything in it.

Pull the sensor plug out of the socket - light should go off. Bridge the connections - light should go on. If that works the wiring is probably OK......

[Sharkey R]

The light stayed on when it was unplugged.

[Sharkey R]

The bit I don't get is why would the light go out when you push the float down to the bottom of the tank and then as the float rises back up the light comes back on?

[jamesy12345]

That's odd - looking at the wiring diagrams the float completes the circuit, so unplugged sensor should be open circuit & no light...any break in the wiring could send 12v to earth though that's what I was thinking.

See page 85

http://www.volvowiringdiagrams.com/v...20Diagrams.pdf

sensor component number is 7/73

[Sharkey R]

I'm rubbish when it comes to electrics so I think I'll pop it in to the specialist I use and see what he can find. Just seems weird it all started when I changed the tank.

[Marc Lenssen]

Change back to the old tank and see if that helps?

[Harvey]

Do you still have the old tank tape up holes then plug it in then fill it up to the line does the fault lamp stay off.
Could be a bad batch of tanks sensors !

[Sharkey R]

Unfortunately I didn't keep the old tank

[Sharkey R]

I've just bridged the socket for the coolant level sensor switch and the light goes out. Does that mean the sensor is giving a wrong signal?

[stribo]

I bridged the connector last week, and the light went out, so the wiring's fine, I think I still have your old tank Steve.

[Harvey]

I bridged the connector last week, and the light went out, so the wiring's fine, I think I still have your old tank Steve.

Just wondered what sort of warranty is given for the work done.

[stribo]

Just wondered what sort of warranty is given for the work done.

Warranty doesn't come into effect until the bill's paid. Also it's a part that's faulty, not my work.

[V70 Graham]

I'm glad I didn't go now, my tea would have been to blame no doubt.

[jamesy12345]

I bridged the connector last week, and the light went out, so the wiring's fine, I think I still have your old tank Steve.

I better get out & try mine but sounds like it's opposite from what I said above....maybe pointing at the car doesn't like the aftermarket tanks?? It would be unlucky to have 2 bad sensors

[stribo]

I'm glad I didn't go now, my tea would have been to blame no doubt.

The way you make tea, yes.

[Sharkey R]

Cheers for the input guys. Think I'm tempted to try a genuine sensor first, the float seems to move freely in the tank so I can't imagine its that. I'm away all week with work so I'll try it on Saturday.

[V70 Graham]

Another R to be broken....