Weird overheating problem

[Unfolded-V8]

Ok here it goes

from cold it starts fine ill take it for a 5-20 min drive and turn it off.. leave it for about 20 mins and i try to start it and it struggles to turn over.. and going through drive thrus etc, it starts going up too the H mark in a matter of minutes.. i can hear the thermos running..ive checked coolant and its fine

any ideas to what this could be?

thanks

[banga]

could be a stuck thermostat, when its cold take it out and change it , if the old one has scratches on the side of the center shaft its usually a good indication its been sticking , your radiator could be blocked as well , that will cost you more to get done ,so change the thermostat first and if problem persists then take the radiator out yourself and take it to a radiator shop to get cleaned , they will check the overal condition of it also if they know what they are doing , hopefully thats what will fix it , good luck ps: taking it out yourself will save you a pack of money in labour costs ,

[Unfolded-V8]

could be a stuck thermostat, when its cold take it out and change it , if the old one has scratches on the side of the center shaft its usually a good indication its been sticking , your radiator could be blocked as well , that will cost you more to get done ,so change the thermostat first and if problem persists then take the radiator out yourself and take it to a radiator shop to get cleaned , they will check the overal condition of it also if they know what they are doing , hopefully thats what will fix it , good luck ps: taking it out yourself will save you a pack of money in labour costs ,

How much is a thermostat ment to be opened once it reaches the right temperature?