Please can anyone help me

I have a nissan primera p12 auto 2.0 petrol 2002 model sve

Just recently i have had an issue where the fan would come on pretty quickly and then speed up to the top speed pretty much after that quickly. I have on 2 occasions been sat in mcdonalds drive thru the fan kicked in then the temp gauge goes up nearly to the red and then a warning on centre console saying its overheating. I Started the car tonight after being at my fathers for about 30 mins the temp had not dropped it was still in its normal postion around a 3rd up the gauge so all good after 5 mins of engine running fan kicks in then 5 mins later goes onto higher speed. Temp gauge moved a bit just to about half. I set off from my fathers and hit the a38 doing 60mph for about 5 miles temp gauage still stayed at half. Got back to my place i live sutton in ashfield fans still running like mad still on half temp.

I then gave it some boot and temp seemed to drop back to about a 3rd but fans still on top speed as i could hear them running. Parked up outside my house and fans still running fast.

The point of overheating has happened twice now but no steam etc. I have had to fill the metal topped rad at front twice to brim as advised by garage, The water isnt leaking its going into the expansion tank on the leftand taking it well over the max but  this has happened twice to me where i have to fill it up and empty some from expansion tank then its all good for a couple of weeks and does the same again.

I have had the following checked

Took to a garage they left on ramp and said fans kicked in temp dropped and then fans went off but i cant get it to do that?

Had the engine pressure tested results were fine so not head gasket.

I have bought a new thermostat although not fitted yet a someone said its unlikely?

Anyone that can help me please i love my p12 its done 70k and has regular services i just hope this is something and nothing but any suggestions would help

Had the cap changed no difference also so not rad cap

I hope someone can help me

Thanks

John

Hi maybe I am saying wrong by pressure test garage had it a day and said it's deffo not a head gasket issue but could not tell me what the issue was. It's also not steaming and also not listing any coolant and oil is clean. So I doubt it is head gasket as I say I am no mechanic but garage said this to me. I will try changing the stat see if that helps but after that will see what happens it's doing my head in now if it does not fix it will just sell it as it's driving me mad. Spent loads getting it right and don't need the head ache lol thanks for your advice really appreciate it.

Ok I appreciate your advice. Are water pumps a big job thank you again john

hi Electrolyte thats a useful tip thanks and also want to say i took for new thermostat fitted today when they stripped down someone had removed the thermostat so that is weird anyway all fitted now and still have the same issue will try water pump test as you suggest and see if that works tomorrow if not  i am not at a loss went up motorway at 70mph for 5 miles today came off motorway and fans were on full blast and temp was about half its doing my head in now lol