Mikeyjames123 said:

Hi looking for some advice …
Got a defender 200tdi had cambelt and water pump around 6 months ago all being fine and then few weeks ago towing my caravan the temp gauge crept up to just under the red and then the windscreen steamed up ( heater matrix popped) replaced heater matrix and then did the thermostat at the same time but ever since the temp gauge goes up to just under the red thought it was a dodgey stat so ordered a new one again and still the same then noticed my radiator wasn’t the best so I put a new rad in and yet another new stat and it’s still the same so ran it with no stat and the temp wouldn’t rise at all … so ordered another new genuine stat and the temp garage ranges between 3/4 and the red the engine doesn’t feel or smell that hot and done a 80 mile trip with a trailer and it didn’t rise anymore and didn’t smell hot or anything but still showing just in the red on the gauge so tried a new sender and still the same been out green laning etc and towing trailers all day but it isn’t over heater
So all together it’s had 6 thermostats
A new radiator
New heater matrix and pipes
New temp sender
Water pump 6 months ago
And still the same
Only ever started with this problem when I first changed the thermostat and the matrix can anybody point me in the right direction thanks

(engine is the original defender 200tdi not discovery!)

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Turboman said:

There is a possibility of a blockage within the block itself, or a blocked bypass hose, something like that.
But it is also possible that your engine is running at the right temperature, and there is an earthing fault with the gauge itself.

I suggest you buy an infra red temperature pen, they are available to buy online, and go over the engine, rad, hoses, etc. to get an idea of what is actually going on.
If the engine seems to be about thermostat temperature, and the hoses etc a bit cooler, as you would expect, have a look at the earthing of gauge and instrument cluster.

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Mikeyjames123 said:

hi thanks for your reply yeah I have ordered one just to double check …
The top hose gets pretty hot but the bottom hose is stone cold and after I have been towing good weight it’s still the same and I can open the header stand and the water is stone cold and doesn’t seem to have any pressure there at all not sure if that’s normal or not ?

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Turboman said:

200Tdi are an engine that runs pretty cool. But I think the water in the header tank should be warm, at least.
There should definitely be pressure in the cooling sytem, only about 7psi, I think, but pressure.
Have you tried a new pressure cap on the header tank?

Going to tag @lynall on this one, he knows more about Tdi than me.

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Turboman said:

200Tdi are an engine that runs pretty cool. But I think the water in the header tank should be warm, at least.
There should definitely be pressure in the cooling sytem, only about 7psi, I think, but pressure.
Have you tried a new pressure cap on the header tank?

Going to tag @lynall on this one, he knows more about Tdi than me.

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lynall said:

If it still has the viscous it is very hard to get them hot, in the winter it is nigh on impossible.

I have a proper temp gauge in mine, and on way to old job would see temp climb above normal, then stat would open and temp would drop to its normal low 80s operating temp, but in cold winters i have seen it drop back down to low 70s as the rest of the journey was downhill and the engine cooled down and stayed cold!

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Mikeyjames123 said:

Great thank you and no I haven’t I will order one to see if that makes any difference and il look at the earths etc over the weekend by then hopefully my infra read temp reader will be hear thank you for your help

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Mikeyjames123 said:

hi yes still has the viscous van and yeah I had never had a problem before untill the matrix went and I changed the stat and matrix now having this issue I don’t feel as if it’s getting hot but I do feel like it’s holding the heat to much at the top of you get me like I would of thought the bottom hose would atleast be warm but it’s not it’s stone cold like it’s not circulating correctly I have just ran out of ideas

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lynall said:

New stat duff, they are all junk nowadays.

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Mikeyjames123 said:

Do you think ?? Sure out of 6 I would have had one decent one ? Do you recommend a make of one to go to as I think iv had every single make now ‍

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lynall said:

Bit of googling suggests waxstat are still in business and they make stats for the 300 onwards, twice the price of the cheap 200 ones, wonder if the 300 one minus the rubber seal would fit in the 200 recess?
Ebay search land rover waxstat.

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Mikeyjames123 said:

Yeah that’s the same as mine the last one I put in was a gates one sure it was around £45 ‍ tried all different makes etc but il have a look for them now cheers buddy

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Turboman said:

Another thing you could try is to remove the thermostat altogether, and drive around for a bit.

If the gauge still says you are overheating, you can be fairly sure it is a gauge issue.

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