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Temperature sender replacement

Posted: Mon May 30, 2016 9:18 pm
by jprenaud
Dear All, The engine temperature gauge stopped moving about 10 days ago on my 2.5TB. I have not lost any coolant. The rest of the van seems to be working completely as usual although I've had some heating issues but it's been quite warm recently and I don't run the van much.

I planned to replace the sender on the head this past week-end, but I did not realise I would have to remove the engine top cover and also I did not have the right size box spanner (tricky access really) so could not do it.

On Saturday I shorted the cable to an earth and the needle on the dash went to hot so I understand that side (cable to gauge) is working fine. I also cleaned the blade on the sender and the gauge moved a wee bit on a test drive afterwards but it still is not working so I'm planning to replace it this week-end. (As an aside the blade on the sender looks like it was "soldered", it's not held by a rivet holding like the genuine Mazda replacement I have since bought.)

Now my question is: what happens when the temperature sender is malfunctioning? Is it merely the gauge on the dash not reporting the temperature, or does it impact the engine temperature control/heating controls? I'm just wondering whether I should run the van at all.

Also, before I try and replace it again, any tips or things I should be looking out for? As far as I've seen, after top cover removal a size 12 box spanner should be all I need, right?

Any comment very much appreciated.

Re: Temperature sender replacement

Posted: Tue May 31, 2016 9:31 am
by g8dhe
The gauge sensor ONLY affects the display, there is another sensor that feeds the ECU for control purposes, so no worry there.

Re: Temperature sender replacement

Posted: Tue May 31, 2016 11:28 am
by rita
Hi you don't need to remove the "top cover" simply lift the drivers seat and use a suitable socket and ratchet, fitting the socket first then the ratchet.
Make sure that the cap is secured on the header tank, you should not need to bleed the system after you have changed the sender unless you have lost a large amount of coolant.

Good Luck.

Re: Temperature sender replacement

Posted: Tue May 31, 2016 11:46 am
by cmm303

Re: Temperature sender replacement

Posted: Tue May 31, 2016 1:34 pm
by rita
I think they are referring to the Temperature Gauge Sensor not the ECT sensor.

Re: Temperature sender replacement

Posted: Tue May 31, 2016 2:48 pm
by cmm303
rita wrote:I think they are referring to the Temperature Gauge Sensor not the ECT sensor.
you are right!

Re: Temperature sender replacement

Posted: Tue May 31, 2016 9:25 pm
by jprenaud
g8dhe wrote:The gauge sensor ONLY affects the display, there is another sensor that feeds the ECU for control purposes, so no worry there.
Thanks, it's reassuring that it's not impacting anything but the display.
rita wrote:Hi you don't need to remove the "top cover" simply lift the drivers seat and use a suitable socket and ratchet, fitting the socket first then the ratchet.
Hmmm, it did not look that obvious to me but I did not have the right socket anyway to accommodate the length of the blade on top of the sensor. I'll tell you how I get on.