water circulation issues!!

i drive a 300tdi defender and its been overheating with a thermosat in place, but once removed the cars ok, just runs cold, or just under half way

now ive Just tested my old thermosat and it opens so thats not broken!!

does any one know how i can tell if the water pump is working or not? I have no strange noises coming from anywhere so i cant hear that its not working!!!

or could it simply be that i need to bleed the system because of and air lock or something??!?

Cheers

Harry

and at which temp is it opening??

gozitan said:

and at which temp is it opening??

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I wouldnt know, boiling water in the microwave took 3 mins, and thats when it opened!

so im guessing 100 degrees?!

it thats the temp its opening, then you found your problem. it should open at about 85C. but do check it properly by putting it in some water together with a thermometer and heat it over a gas burner or something slowly

gozitan said:

it thats the temp its opening, then you found your problem. it should open at about 85C. but do check it properly by putting it in some water together with a thermometer and heat it over a gas burner or something slowly

Click to expand...

ive got a new one in there now, and still have the same problem,

ive now had the water pump off, and it turns smoothly and looks fine,
ive flushed the whole system out with hot water, just incase of any frozen pipes,

flushed out the radiator from the bottom, no blockages there,

re filled the system with fresh anti freeze etc etc

taken it for a run, goes to over heat, theres never any steam and the header tank is never hot or anything,

but again if i take out the thermostat in the morning, it will probably run fine!!

How are you measuring the "over heat" ?
Is your temp gauge working OK?
Is your temp sender working OK?

Maybe its not really running hot.

Shifty1962 said:

How are you measuring the "over heat" ?
Is your temp gauge working OK?
Is your temp sender working OK?

Maybe its not really running hot.

Click to expand...

well im not letting it over heat,

but after a few miles, where it would normally heat up to half, it just creeps up and up and then once it touches the red i turn it off, dont wanna risk it boiling up and blowning the head,

so it technically hasnt overheated yet,

tomorrow morning im going to run the engine with the header open to make sure i have no air in system,

also take the dash apart make sure all contacts on the heater gauge are ok and then also check out the sensor on the engine, where ever that is!