Flat rad. hose
 

Its happend for the 4th time now. Seems like when I run the truck hard like when offroading the top radiator hose gets sucked flat and this time the bottom one did also. I have only noticed the temp guage showing warmer then normal maby 2 times out of the 4. I have replaced the thermostat once already, and flushed the radiator and block out. I was thinking maby the radiator cap was bad.... What do you guys think it could be?

Edit: ohh and if I take off the radiator cap then the vacuum is released and the hose returns back to its normal shape..

its called replace your hoses..

Actually the more I think about it, I see it being the hoses. Once the hose collapses then it creates a larger vacuum.....
I feel stupid that I didnt think they would be the problem.:duh[1]:

thanks

I just had my rad. flushed and my upper and lower hoses went flat and it was the just radiator cap.

thats usually caused by a bad cap

Well I already bought the hoses, Ill put them on and if it does it again ill get a cap. The hoses that are on the truck now if you squeeze them then you can hear stuff crunching inside them even after washing them out, and I think they are originals.

The cap didnt fix it it has happned 2 more times. I have replaced the water pump, got new hoses, put a new thermostat on, and every time after I have had vacuum in the lines and it just made my engine light come on.