Over heating 110 1985 300tdi after rebuild

Booked for mot after 4 years messing..took her out and she got hot..replaced thermostat and replaced sensor ..still got hot checked all pipes.. the engine is getting over hot on 1 mile run the radiator stays cool..my thought is water pump has gone during off time but thought i'd ask..

Have you used the correct sensor?
If it’s a disco engine the sensor reads hotter on the landie gauges

Have you tried flushing the rad to make sure it's not blocked with crud?

Are the gauges grounded properly? They read with an offset if theyre not.

Pretty much all the diesel land rovers take 2 plus miles for the stat to open, and in winter can be as much as 5 miles
So the fact you are having issues straight off would suggest leccy fault.

I had a similar issue and angst, I thought the engine was getting too hot, cos the gauge said so.
I felt the engine and the radiator in the same way .... and was convinced that after a short while the engine was over heating and the radiator was stil cool.

It was an earth issue in the dash and when it was fixed I realised the engine wasn't gettin 'too' hot, it was just getting hot as one would expect.
When the engine is up to temp (ie normal), the thermostat is open and the pump pumping, you can't touch the engine or the rad as it's around the 80C mark.

Thanks for the replies to answer a few … I’ll check the clock ground and flush the radiator…but it goes up steadily
It’s a defender engine so I’m guessing I have the correct sensor
Not sure I’m brave enough to run it to mot with the gauge reading that hot!

It does take a leap of faith ....

Are the heater pipes getting warm ? Possible air lock maybe.
An after market capillary type temp gauge that reads in numbers degrees will let you know what the temp actually is.

farriermatt said:

Thanks for the replies to answer a few … I’ll check the clock ground and flush the radiator…but it goes up steadily

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Without the gauge grounded, they work just like they would do, but just with an offset. (I did say this before)

They don't suddenly jump to red. They rise as per normal but just keep going past mid way and into the red.

It was a dodgy earth on the back of the gauge I’d just fitted a new speedo cable so guess I buggered it then.. thanks everyone.

farriermatt said:

It was a dodgy earth on the back of the gauge I’d just fitted a new speedo cable so guess I buggered it then.. thanks everyone.

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The best possible result. Well done.

I, on the other hand, changed the radiator and flushed the coolant system before realising....

In fairness, I could see my hand on the other side of the radiator, so it wasn't a terrible thing.

(Don't pressure wash old radiators - the fins just all come off!)

julianf said:

I, on the other hand, changed the radiator and flushed the coolant system before realising....

In fairness, I could see my hand on the other side of the radiator, so it wasn't a terrible thing.

(Don't pressure wash old radiators - the fins just all come off!)

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Better finding out this way than when it causes your truck to overheat and requiring the cylinder heads on your V8 to be skimmed!