TD5 Temp guage says hot - motor is cool (intermittent)

[fisherolf]

G'day all:

Hoping someone can help. My TD5 Disco went into limp mode last week, with the temp guage reading high. Panic naturally set in, but when I popped the bonnet the motor was actually quite cool - in fact I was easily able to open the coolant filler cap with very little back pressure and there had been no loss of coolant??

Apart from 2 seperate occasions where the temp guage rose slightly higher than normal, everything currently seems to be okay.

Is it possible to have an intermittently flakey temp sensor or am I seeing the beginnings of something more sinister??

I'm not getting any younger, so don't go out of your way to give me a heart attack with unnecessary horror stories, but any informed assistance would be greatly appreciated.

Cheers

Rolf :o

[Blknight.aus]

earthing fault in the dash, ecu or the engine would be a likely start point

if youve got a nanocom or similar plug it in and watch it while you drive if its a sensor or wiring fault it will throw a code not so much when its an earthing fault.

I have also found that scrupulous attention to all the earths can also cure the intermittant crank angle sensor noisey fault...

[LandyAndy]

Oil in the harness to start with.(Search "Oil in the harness")
Thermostat after that.
Then start hunting faulty earths!!! Grab a RAVE CD(electronic workshop manual CD) from here Dave's Interesting Things (http://www.davesitshop.com/davesitshop/) ,sales support AULRO!!!
You will need the RAVE CD to locate the earth points!!!
GOODLUCK
Andrew

[fisherolf]

Thanks to both Blknight & yourself for responding. I do have a copy of the Rave CD, so I'll checkout the earth points as a matter of course.

Having heard so much about the "oil in the harness" problem, the harness was replaced 30k ago as a preventative measure - but it will certainly be checked again.

Your thermostat suggestion did set alarm bells off, as it prompted me to recall that a few days after the "limp mode" incident the heater failed to heat one morning (mornings in Melbourne can be cold too !!). The heater only failed to heat that one time and has been fine since.

The thermostat not opening would account for the heater failing, but wouldn't it cause the motor to physically get hot and the coolant to boil??
No-one has mentioned the temp sensor, so am I to believe that they are fairly robust and rarely fail?
Thanks again for your assistance
Regards
Rolf

[Blknight.aus]

the thermostat not opening wont cause a heater problem. poor bleeding after its replacement will.

[Zute]

You need to get a Nanocom plugged in and watch the temp from cold to hot.