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Marks 110

Testing 200tdi temp gauge(s)

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Thought I'd try and test my temp gauge this afternoon as I think I may have a cooling problem. Had a (cheapish) digital gauge fitted for the last couple of years but never been too sure on the accuracy.

Anyway here's what I did

Got a pan of boiling water bubbling away on a gas camping stove

Unscrewed sender and immersed in pan along with two digital thermometers

During a rolling boil thermometers reading 100-101 deg as you might expect

Digital gauge reading only 93-95 degrees (this is worrying as it reached 90 deg while driving through the french pyrenees so was prob close to overheating)

Also tried it wired direct from battery terminals but made no difference

Then refitted original land rover gauge and did same

During rolling boil gauge is reading just past the 12 o'clock position

Is this what you would expect?

I know with the system pressurised (Rad cap is rated at 15 psi) the coolant will get above 100 before it boils but how hot can it get?

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The original Land Rover coolant gauge fitted to a Defender with the needle in the middle will shew a coolant temperature of 86 degrees or the coolant could be at 98 degrees C

Take your pick. That's how accurate the Land Rover gauge is.

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The original Land Rover coolant gauge fitted to a Defender with the needle in the middle will shew a coolant temperature of 86 degrees or the coolant could be at 98 degrees C

Take your pick. That's how accurate the Land Rover gauge is.

By design though. All car makers do this with their temperature/pressure gauges & senders. Generally people are stupid and would panic over the normal temperature variations that actually happen. So they make the gauges non-linear, they'll only move if there's a heat problem big enough to be outside the normal range that the engine would experience during driving.

Some aftermarket gauges are more linear, and you can actually watch the engine heat up and then cool down as the thermostat opens, for example.

There's also the variation that will occur between manufactured gauges/senders, two Land Rover gauges would probably read slightly differently off the same sender, or vice versa.

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By design though. All car makers do this with their temperature/pressure gauges & senders. Generally people are stupid and would panic over the normal temperature variations that actually happen. So they make the gauges non-linear, they'll only move if there's a heat problem big enough to be outside the normal range that the engine would experience during driving.

Some aftermarket gauges are more linear, and you can actually watch the engine heat up and then cool down as the thermostat opens, for example.

There's also the variation that will occur between manufactured gauges/senders, two Land Rover gauges would probably read slightly differently off the same sender, or vice versa.

So best stick with original gauge and not be worried by fluctuations in temp? I guess by the time it hit the red it would be to late to worry as the engine would be cooked!

I'm only worried as vehicle has blown two head gaskets although since changing to elring gaskets on this and a mates vehicle we've not had a failure.

Cheers mark

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If I thought I had a cooling problem I'd fit a matched gauge and sender from a reputable manufacturer (ie. VDO).

My vehicle's have standard gauges and standard cooling systems, except for one fan, and I'm happy with them.

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If I thought I had a cooling problem I'd fit a matched gauge and sender from a reputable manufacturer (ie. VDO).

My vehicle's have standard gauges and standard cooling systems, except for one fan, and I'm happy with them.

Will probably go for that option. What running temp would you expect?

Mark

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Yes stick with the original unreliable gauge. Then when your engine overheats with the needle just over the vertical you know who to blame.

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Will probably go for that option. What running temp would you expect?

Mark

I would have thought around 90 degrees under normal conditions, stat opens at 88 so should hold it around there.

Yes stick with the original unreliable gauge. Then when your engine overheats with the needle just over the vertical you know who to blame.

Yes, myself for not maintaining the vehicle properly. Not everyone drives across deserts remember.

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I would have thought around 90 degrees under normal conditions, stat opens at 88 so should hold it around there.

Yes, myself for not maintaining the vehicle properly. Not everyone drives across deserts remember.

Nut just deserts, the M1 is as bad

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Iirc on the disco with air con the coolant temp had to be 110 deg c before the a/c fans switch on automatically to help out, this was on a 300 auto i owned and im sure td5 is the same.

In my series2 i have a cappiliary gauge from a a mini fitted cost about 20 quid new from e bay.

Lynall

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Iirc on the disco with air con the coolant temp had to be 110 deg c before the a/c fans switch on automatically to help out, this was on a 300 auto i owned and im sure td5 is the same.

In my series2 i have a cappiliary gauge from a a mini fitted cost about 20 quid new from e bay.

Lynall

Just been out for a drive with the standard landy gauge fitted. After 10 mins temp is past halfway on the gauge - the same reading as it was submerged in boiling water!

I'm sure there must be a problem with the cooling but the system has been replaced (rad, pump, thermostat, gauge and sender) which makes me think the engine might be generating too much heat for some reason??

Any ideas?

Might get the injectors/pump reconditioned but as engine runs very well (a touch of black smoke when accelerating hard but will do 80mph) this is probably money down the drain.

Suggestions welcome.

Cheers Mark

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Mark

Maplins could have a definate answer for you. They sell a small hand held thermometer that you point at the heat spot. I think there's a post on here about them.

Get one and you get the definate temperature answer.

HTH

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