Thread: Water temp spiking on hills...what to look for

Thanks guys.....

Yep two driving lights and a winch

340k on the clock, I have no idea if it's the original fan.....

yea i had the same replaced my head gasket 100,000ks ago,blew back of no 4 just oil not water,after that towed our camper from cairns to mt isa up through the gulf, was fine on the flats and dirt soon as we hit hills or sand started to get warm, up around 80 opened up the heater and she cooled a bit new it wasent normal had not done it before, put a new radiator in extra cooling row now great pulled a ton and a half up the toowomba range raised a bit but that was a bad gear change allso running a v8 thermostat dont know if that makes a differance seemed like a good idea at the time dont have spotties just a winch i think they are a badly desiend cooling system
allso running full maxi drive conversion,heavy cvs, wrangler muddies,2inch lift,stronger steering arm,heavy bash plate,front diff guard jackable side steeps,warn winch,bigger intercooler,front diff guard,double cardon front shaft,

That is the key, these systems are way too small for heavy hard working Defenders etc in high ambient temps, so the rad that IS there needs to be exemplary.
A bigger more efficient radiator can only help

JC

Originally Posted by justinc

That is the key, these systems are way too small for heavy hard working Defenders etc in high ambient temps, so the rad that IS there needs to be exemplary.
A bigger more efficient radiator can only help

JC

I've thought more than once over the years of installing a big oil/air cooler to take some load off the cooling system, as IMO the current oil cooler is massively undersized too.

Certainly rick, in a Defender It would be quite easy to use a County full width radiator, replumb a full width front mount IC and then still retain a seperate engine oil cooler and A/C condenser. Using the extended 110 grille it'll all fit, well mine does I had to move the rad back about 20mm because I have a ginourmous 75mm thick intercooler....but a Tdi doesn't need to be that huge.
Or Just fitting the Td5 rad and intercooler pack will be pretty easy, all the brackets bolt straight in to county v8/ isuzu, and Tdi defenders. You just have to make up a pair of lower rad support plates like the Td5 has . That is how we did the last Isuzu conversion, used the Td5 rad and IC, very minimal mods to plumb it and fit it all up, cooling system is fine using the Tdi expansion bottle and the vehicle weighs in at 3400Kg in touring duty guise, temps seem fine.


JC

Those huge lights arent going to be helping the situation


I just got home from touring NSW, up to Lightning Ridge via Dubbo, then Bourke, Cobar to Ivanhoe , Mungo & home via Balranald
Only saw one other Defender the whole trip

WOAH STOP RIGHT THERE!!!!

None of you have checked the obvious... Is the temp gauge actually giving you the correct information? It may well end up being a blocked rad, etc... But check the simple & cheap stuff first.

Borrow/buy a laser thermometer, go for a drive, reproduce the problem, jump out and measure the temperature. The ideal place will be the thermostat housing.

The reason I say this is that a faulty earth to the engine will make the temperature gauge over sensitive and you'll think that you are overheating when actually you're not.

M

Originally Posted by camel_landy

Borrow/buy a laser thermometer, go for a drive, reproduce the problem, jump out and measure the temperature. The ideal place will be the thermostat housing.

If this hasn't been done already then doing this should be first on the list.

The reason I say this is that a faulty earth to the engine will make the temperature gauge over sensitive and you'll think that you are overheating when actually you're not.

As the engine temperature rises, the temperature sensor allows more current to flow through it, so by removing the wire to the sensor ( open circuit ) when the ignition is in the run position, the gauge shows cold and then by placing a test light ( low impedance ) between the wire that goes back to the temperature gauge and a good earth the gauge then should show a hot reading.
So therefore, poor earthing somewhere between the alternator and the negative terminal on the battery will allow the voltage to rise between the engine block and the battery. This then can show up as a faulty hot reading on the temperature gauge.

Check that the earth straps between the battery to the chassis and the earth strap from the flywheel housing to the chassis are in good condition, not frayed and most important ! where the surfaces are that they are bolted on to, is as clean as, use some conductive grease on the surfaces and everything is then done up tight .

The next earth / current path to check is between the side of the temperature sender body and the engine block. Turn the ignition switch to the run position and on the 300TDi you should hear the fuel cutoff solenoid click once as it engages, then using a multimeter, measure for voltage between the engine block and the body of the sender unit, there should be a reading showing zero volts.

Any voltage reading at the sensor to the engine block, means there is poor current path somewhere between the those two measuring points , so investigate !

This check will not show up an internal fault in the sender however, to determine the condition of a sensor, substitute with a known good or new unit.

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