newbie - Thermostat or W/Pump

[Wayne MK4 1.8T]

2001 Golf Mk4 1.8t 20v 150bhp

When out this evening the temparature started to creep over 90, which it has never done before, there was also a loss of power, it felt very sluggish as if i was trying to pull away in 5th gear, the air con didnt seem to get warm as quickly as it should. I stopped to let the enginr cool, it soon dropped back to 90 but as soon as I tried to drive it started to creep up again, so much so that whilst trying to go up a small hill I could see the needle moving, I was very careful not to let it get past 100 and limped home stopping all the time and coasting as much as poss to keep it as cool as possible, no oil in the coolant and the coolant was not bubbling, the fans seem to be working ok. Whilst idleing it was fine, temp stuck at 90, revved up ok, no noises, no leaks from underneath, no smells. Not sure if the steering didnt feel heavier, but I was paranoid by that point and may of imagined it. Any advice would be great! Thanks.

So symptoms are: Overheating - Loss of power

[FLENG2008]

check the water pump by pulling off the return hose to the header tank

check the thermostat by testing the bottom hose see if it gets warm after a run

my car runns sluggish when it overheated once i think its like a limp home mode or something im not sure

[Wayne MK4 1.8T]

Well the chap has just been to look at it and says that it is the water pump, as the air con is not blowin hot and fluid is not being returned to the coolant tank, and I suppose seeing as this seems to be a very common fault its more than likely, so gonna take the plunge with it I think and get the cambelt done at the same time. Should it not be the pump, is the replacement of the stat a DIY job on this model, Im not a mechanic but I am far from stupid, at least I think so anyway, is it poss to now get a replacement w/pump with a brass impeller

[FLENG2008]

Well the chap has just been to look at it and says that it is the water pump, as the air con is not blowin hot and fluid is not being returned to the coolant tank, and I suppose seeing as this seems to be a very common fault its more than likely, so gonna take the plunge with it I think and get the cambelt done at the same time. Should it not be the pump, is the replacement of the stat a DIY job on this model, Im not a mechanic but I am far from stupid, at least I think so anyway, is it poss to now get a replacement w/pump with a brass impeller

ok go for the water pump they come with metal impellors now
get a genuine one cause the price is reasonble and warranty for 2 years

do the stat first tho if you dont trust the garage

[Wayne MK4 1.8T]

Hi I have made some enquiries with regard to parts, upon phoning GSF Parts I have found that an

Airtex W/Pump is £32 with vat and a Belt Kit is £56 with vat., which differs from what my mech' has told me, do these prices sound correct and what should a belt kit consist of.

Model Golf 4 1.8T 20v 150BHP, Eng:AUM