300tdi overheating

Have a defender 110 300tdi,

Symptoms- warms up quickly, gauge sits in the middle unless under load then creeps into red. But coolant is only warm not scolding and hoses not solid and hardly any pressure when removing the cap.

So far ive attempted to flush the radiator which is pretty much impossible due to design.

Fitted new stat, water pump, flushed, bled (everyway listed on forums) and washed out the fins in the rad.

So looking at temp sensor n new radiator but don't want to be wasting money on things I don't need.

Any thoughts?

Could be a disco engine? Incorrect sender for a Defender?

No its an 1998 defender correct engine and sender (black collar) , its only just started doing it

If the hoses are only warm then the stat is faulty (I know it's new but not unheard of) or sender or , less likely, the gauge. You seem to have covered everything else.
Are the heater hoses very hot? If not, it's not overheating (unless it's air locked) and I would suspect the sender.

Heaters are working as shud as in it gets warm, unsure of the hoses tho

Rad666 said:

Have a defender 110 300tdi,

Symptoms- warms up quickly, gauge sits in the middle unless under load then creeps into red. But coolant is only warm not scolding and hoses not solid and hardly any pressure when removing the cap.

So far ive attempted to flush the radiator which is pretty much impossible due to design.

Fitted new stat, water pump, flushed, bled (everyway listed on forums) and washed out the fins in the rad.

So looking at temp sensor n new radiator but don't want to be wasting money on things I don't need.

Any thoughts?

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Is the coolant circulating sufficiently, if you remove the header tank cap and rev the engine you should see movement of the coolant, if this is not happening the water pump may not be pumping, impellors can break or become detached from the pump shaft.

Water pumps brand new, ive taken rad off and having it recored on monday so fingers crossed its that

Could the temperature sender wire be shorting out somewhere?
If it shows high again (but not obviously ACTUALLY overheated), try gently unplugging the sender plug from the sender (gently so you do not move wiring), and see if your gauge shows nothing ie no needle movement. If the needle moves at all, the cable is at fault.
Andy

Are you 100% sure it's over heating? Is the water actually too hot?

Or is the gauge reading that it's too hot, but it actually isn't. Reason I say this, had identical symptoms some time back; fine under no load, or revs. As soon as it was loaded or revs the gauge used to shoot up, all down to a poor earth.

Get a infa red thermometer on the water ways to double check temp

ONE LIFE LIVE IT. D90 said:

Get a infa red thermometer on the water ways to double check temp

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Be careful of the IR thermometers, they can give some dubious results. Due to surface finish / material and the area you are pointing at due to the cone effect over the distance from the target. A surface contact probe is a much better option.

Cheers

Cheers for the replys, where are the earths i should be looking at?

Ive fitted the rad but have had chance to take it out for a run yet, the bloke who recored it shoed me the old one and it was partially blocked.

also have a new temp sensor getting delivered today just incase it was that

Back of the gauges for earths if nowt else is playing up.

ONE LIFE LIVE IT. D90 said:

Are you 100% sure it's over heating? Is the water actually too hot?

Or is the gauge reading that it's too hot, but it actually isn't. Reason I say this, had identical symptoms some time back; fine under no load, or revs. As soon as it was loaded or revs the gauge used to shoot up, all down to a poor earth.

Get a infa red thermometer on the water ways to double check temp

Click to expand...

+1 - Your temp gauge is just that a gauge - I.E. it meant to offer a rough idea of the temperature - and they can play the fools for a number of reasons.. ( some detailed above )

If the coolant is not HOT, then it is NOT overheating.

IMHO, measure the temperature with a proper thermometer, or a capilliary gauge ( which is more accurate ). I also agree with @neilly 's remarks regarding the IR thermometers - very good, but care is needed during use....

Been out all morning, various hills where it would over of definatly raised the temperature and it stayed in the middle. So im going to go with the radiator was at fault and not circulating the water efficiently.

Will be checking earts behind clocks this afternoon for piece of mind, thanks to everyone who commented

Radiator was recored at

Master radiators
Middlesborough

Checked earth point on back of gauge, nut wasnt as tight as id of liked but apart from that seemed fine

Rad666 said:

Checkes earth point on back of gauge, nut wasnt as tight as id of liked but apart from that seemed fine

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On mine it wasn't the back of the gauge earths. It was the main battery earth to the chassis

ONE LIFE LIVE IT. D90 said:

On mine it wasn't the back of the gauge earths. It was the main battery earth to the chassis

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Is that under the seat box?

Rad666 said:

Is that under the seat box?

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Yes, bolt on to the chassis between the inside rail and the seat transferbox IIRC with a pretty poor 'P' clip crimped to the rail, then at the end earths to the transfer Box.

Same thing has happened with all four land rovers Ive come across of a similar age, it's really worth ruling it out for how long it takes to clean it up to bare metal.