Bizarre Overheating Problem

A year or ago my 1995 Defender TDI300 started intermitently running hot. There didn't seem to be a pattern to the behaviour although it was almost guaranteed to occur when I undertook a 15 minute steep climb ( I live in the mountains ). However the ambient temperature seemed irrelevant. It also seemed to happen frequently when I entered lengthy tunnels. The temperature gauge would move so swiftly you could actualy see it move. Most of the time it stops just below the red, but very occasionally it does enter the red but goes no further.

In my attempts to rectify the problem I have :

1> Replaced the sender unit.
2> Replaced the radiator.
3> Replaced the viscous coupling unit on the fan.

Although the problem seems slightly less frequent it is definitely not fixed.

Last night I noticed something really strange - the temp needle actually seems to rise visibly the instant I switch on the headlights ( which explains the swift appearance of overheating in tunnels ).

Can anyone explain a link between my temp gauge and the headlights ?????

Cheers for your thoughts.

Dave

did you change yer thermostat ?

i've got a not to dissimilar issue currently with a 200Tdi

check yer lectricks out.. alt output, earths and any other connections in th eheadlight and dash circuits.

its definatly a bad earth mate i had a similar problem the other week turned out to be a wire thats not used was earthing to the side of my diesl pump every time i increased speed over fifty it went into the red

funny old things landrovers they know how to keep us on our toes

Hi this happened to me as well on my range rover dse. temp guage will jump to 3/4 whenever I opened the a/c especially on climbing. Temp will immediately fall to normal upon turning of the a/c. Turned out to be a bad ground. Check the main ground connection from the battery to the inside fender near the shock tower then from there on to the engine block. If need be just add another thick grounding wire from the chassis to the engine block. make sure you scrape all grime and paint to ensure metal to metal contact. I assume that when you enter the tunnel you turn on the lights which adds an electrical load. Let me know how it goes. good luck

rdb525i
97 disco 300tdi
97 defender 110 300tdi
97 Range rover dse

i have been having the same faults with my range rover dse for about 3 months, it only seemed to start after the water pump went...its really anoying as the engine isnt hot when the gauge is round to the red or the viscous fan would be spinning right up...to try and rectify the problem i have changed the water pump, thermostat, radiator, viscous fan, all temp sensors and its had 200 quid worth of labour in the garage. STILL NOT FIXED IT!! mine shoots right up when i turn the heated screens on...im about ready to give up with it to be honest. i cant keep sending it into the garage to have it back with the problems still persisting.... where are all the earth points on a range rover and which ones are likley to be the cause?? anyone know?? cheers

Voltage Drop ...... bad earthing somewhere .....

Are you sure you really arent over heating? The best way to check is to run the car with the computer attached so you'll end up reading the temp straight from the engine instead of the guage. The grounding points on a dse as far as I can remember are under the fuse box near the battery. there are about 3 points there. One main ground from the battery which also leads to the engine block and 2 small ones right under the fuse box. There are 2 or 3 other grounding points on top of the other fender under and around the EAS box. The rest are under the front seats where another fuse box is located. Good luck

rdb525i

Ooops. I've been ignoring my "overheating" problem, since I decided that it was just an electrical fault and not a real overheat. However I'm currently in a "fix all landy problems" mode so I'll have a check on all of the earth points I can find.

One more detail : I've noticed that the fuel gauge is similarly affected i.e. it also moves right by maybe 20% when I turn on the headlights. Still, not complaining with the recent increase in the price of diesel

Cheers

Dave

I'd put money on it being an electrical fault. If it was the thermostat it would not move suddenly but would climb and remain hot.

I bought one of them infra red thermometers that you point and read the actual temp. It's got a laser to aim and where ever the red dot is the temp you are reading. Cost £20 but has loads of uses.

Infrared Thermometer > Maplin

It will give you a true reading of engine temp despite what the gauge is saying. At least you can be sure you're not doing any damage while you track down the real problem. Diesels hate overheating and are not as forgiving as a petrol engine.

Used it on my XJ12 to see which cylinder was not firing. (aimed at exhaust manifold port for each cylinder and it was obvious which one was cold. Turned out to be a dodgy injector. Also used it to balance my central heating. It can also tell me how cold my beer is.

Good luck and let us know the final fix.

Check the wires for yer dash panel lights and gauges aren't chowed up in yer engine compartment. Mine had come out of the clip which held them in place, rubbed emselves to buggery and wer shortin' against me injin. Didn't notice until we washed some o the oil an grease off and found a whole bunch o wires rubbed back to the metal. My temp gauge had been goin spacky for some time, a good few months. Then eventually the battery warnin light came on. Finally the oil light came on (when I turned the ignition off!), and I thort I best investigate. So its worth havin a rummage around. A few days before we found the broken wires, I could hear a noise like bacon fryin when I was driving around... That was me shorting wires... I could o set me Landy on fire...!

good find! Hows the steerin on the keebab van?

TheVengefulElephant said:

good find! Hows the steerin on the keebab van?

Click to expand...

S'ok now. Still a bit clunky.. but if I turn it left, I go left.. and if I turn it right, It goes right. So am appy.