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

I was going to make the point that if it was the gauge, then why only overread on hills?LOL Clairvoyant electrics?
From what you have posted , IMHO you probably have a number of factors that add up to cause the overheating problem.
1 Spotlights and winch reducing air input
2 disconnected heater core
3 maybe bad VC
4 maybe partially blocked rad( although AFAIR you said it was new.)
5 maybe bad thermostat.

Perhaps try the cheapest things first.
1 thermostats are so cheap ( if conventional type) that it pays to replace, so it can be eliminated.
2 clean up in front of the radiator( move horns if in the way, and test without the spotlights)

Then you get to the harder stuff!
I have read about Nissan Patrols that the problems can be fixed in some cases on TD42s by just moving stuff.
Another suggestion may be to make up your own tropical grille with some mesh.
Regards Philip A

Like Philip A said, why should a meter be faulty up hill only? :angel:

When pulling hard a engine produces the most heat, so is your engine making more power therefore more heat, in other words has the pump been tweaked or is the boost set a bit higher than normal?

With 'Fred' I suspect the boost isn't quite right for the pump settings, does anyone else hear 'cricket' noises from under the bonnet when pulling at 2,500RPM? :p

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Originally Posted by camel_landy

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

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It's a mechanical gauge !

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Originally Posted by wrinklearthur

Like Philip A said, why should a meter be faulty up hill only? :angel:

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In the case of the standard sender & gauge on the 300TDi, a faulty earth can make it more sensitive.

The climbing the hill, just adds extra load, which will make the temperature rise... That faulty earth makes it look as though it is overheating!!!

...and before you all start picking holes in it, I'm telling you this from first hand experience!!! Took me sodding ages and cost a small fortune to find that my Defender was 'Overheating' because of a faulty earth!

M

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Originally Posted by camel_landy

In the case of the standard sender & gauge on the 300TDi, a faulty earth can make it more sensitive.

The climbing the hill, just adds extra load, which will make the temperature rise... That faulty earth makes it look as though it is overheating!!!

...and before you all start picking holes in it, I'm telling you this from first hand experience!!! Took me sodding ages and cost a small fortune to find that my Defender was 'Overheating' because of a faulty earth!

M

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This is very true! Two of our 300Tdi defenders had the same problem, a bad earth causing the temp gauge to rise on hills.. Also when the lights were turned on or the heater used the temp would go up dramatically. I just ran a new earth from the gauge to the engine, has fixed the problem till I get around to buying a VDO gauge..

I seen many people recommend replacing the standard gauge with a VDO unit. Anyone got a model number as another item to add to the ebay shopping list?

Also what about the tropical mod and blocking the hole in the header tank as I heard that causes these symptoms, the hole that is?

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Originally Posted by fesm_ndt

Also what about the tropical mod and blocking the hole in the header tank as I heard that causes these symptoms, the hole that is?

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Thanks fesm

That was the first time that I had heard of that mod and thanks Mate! I did pounce on that info.
This also explains to me why when I have done reverse flushing of a 300TDi radiator that it hasn't been entirely successful, compared many tractor and truck radiator cores that I have washed rubbish out of.

I found this posting on another forum that does explain that tropical mod.

Ref; Overheating 300tdi - Technical - Cape Land Rover Club News Site

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If you own a Defender or Disco with the Tdi 300 motor , are you aware of the strange mod introduced by Land Rover to the radiator ? This mod really appears to be an example of the tea girl altering specs , while the engineers were out of the office. If this has caught your eye , read on...

The hot coolant enters the radiator at the top left side and exits at the bottom left side.(as viewed by the driver in the car ). I would expect that the coolant would have to follow a path that spreads its flow over the entire radiator . But no , there is an opening inside the radiator, about the size of a R5 coin, that allows coolant to by pass the main radiator core and flow directly out of the bottom and back to the engine. Over time the radiator core will certainly show a build up of calcium deposits , thereby forcing an ever increasing portion of coolant to by pass the core. Small wonder then that 10 year old Tdi ' s often develop cooling problems.
There are cases reported where this by pass hole is closed up , eliminating overheating problems . Also owners with modified radiators report a slower warm up after start up.

I intennd as a precautionary measure to have my Tdi rad recored and to close up this by pass .

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Arthur, if you look down through the bleed hole in the LH tank you can see the (bleed) hole in the divider, it's at least the size of a 10c piece !
It's a common mod to have it blocked when you have the tanks off for rodding, etc.

Crazy......

Fesm, the mechanical gauge which I use is VDO part # 180 077 022.

This has a 1600mm capillary, 40-120*C range and the thermowell supplied with it screws straight into the standard sender spot (1/8"-27NPTF)

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Originally Posted by Defendozer

I just ran a new earth from the gauge to the engine, has fixed the problem till I get around to buying a VDO gauge..

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Running that earth can be for piece of mind even if there hasn't been any temperature spiking issues, also there is some real doubt that the sender unit can recover to proper working order after being exposed to overheating, when having problems this sender unit should be replaced.

Along with the effect of electrolysis between the engine and those sensors causing stray currents, it is no wonder that people give that Land Rover gauge the flick and look at fitting a VDO gauge.
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