Odd one.. driving around all day yesterday in the 31c heat, air con on full – temp gauge didn’t budge. Went to the car wash I always go to. Had to stop about 30 seconds later to rescue my Defender (whose fuel line had burst.. another story!) and happened to park the RRS on a steep incline (facing up) for about 3 minutes. When I got back in and drove off, car was in low power mode with the warning “car overheating” and the temp gauge at maximum! Immediately pulled over and relieved to see that 1. engine fan was running 2. coolant still intact and not boiling. Temperature gauge very quickly normalised. About 2 miles later, start driving up a relatively steep hill, temp gauge goes to maximum again! On the flat at the top, back to normal quicker than it could possibly cool if it were actually overheating. So my suspicion of course is that water from the car wash (enthusiastic with the power washer?) has got into a sensor somewhere.

Question is – what sensor, where and will it dry out or will I need to replace?

Drove 150 miles in the evening on the relatively flat motorway without incident and without the temp gauge moving from middle i.e. normal. ============
2010 TDV8 HSE - ooo laa laaaaaaaaa
2007 TDV8 HSE - superb car and very reliable
============
2012 - dearly departed, sadly missed.. to return in late 2013 with a new TDV8!

i had similar to what your describing on my old FL2, driving along the car was fine towing the caravan, hit traffic and the car temp gauge bounced to max and back again within minutes

LRA came out, levels in system all ok and no faults logged, no boiling water etc

10 days in dealer and they came back, when taking the rads out to have them flow checked, that the lower section was clogged with mud, and they decided to wash this out and put it back together

Might be worth a check on yours if used off road

Now my mud had been there for 18 months without issue, so I got the £4 water temp sensor replaced myself as LRCS insisted that could be the cause

Either way, the sensor or the mud was the cause as it never happened again

interesting - thanks for the info. This one hasn't been off road so I don't think it's mud blockage. Bobby - can you shed any light on vulnerable sensors that could have got water soaked, and caused this to happen? ============
2010 TDV8 HSE - ooo laa laaaaaaaaa
2007 TDV8 HSE - superb car and very reliable
============
2012 - dearly departed, sadly missed.. to return in late 2013 with a new TDV8!

local Landy garage say the only sensor that could be affected in this way is the ambient temperature sensor, which is in the front bumper. Not overly convinced tbh! ============
2010 TDV8 HSE - ooo laa laaaaaaaaa
2007 TDV8 HSE - superb car and very reliable
============
2012 - dearly departed, sadly missed.. to return in late 2013 with a new TDV8!

ECT Sensor for an earlier model... should be the same.

Check the wiring/connectors too.

Did any diagnostic trouble code appear? Malaysia Boleh!
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many thanks Bobby - getting the codes read today to see if anything was logged

no codes  ============
2010 TDV8 HSE - ooo laa laaaaaaaaa
2007 TDV8 HSE - superb car and very reliable
============
2012 - dearly departed, sadly missed.. to return in late 2013 with a new TDV8!

Just been having a search for similar issues on Disco3,

http://www.disco3.co.uk/forum/topic50744.html

thanks - because it's only happened once, and because that was immediately after a high pressure wash, and because it was then fine for a 150 mile motorway journey, i am more inclined to think some water penetrated (somehow?!) as opposed to sensor split or completely broken. But looking where the sensor is, it's hard to understand how water could have got to it such a way as to then only cause an issue when going up a hill?!  ============
2010 TDV8 HSE - ooo laa laaaaaaaaa
2007 TDV8 HSE - superb car and very reliable
============
2012 - dearly departed, sadly missed.. to return in late 2013 with a new TDV8!