Hi guys i need your help. my coolant keeps going low but i have no apparent leak. I read somewhere about the cylinder heads being defective in the 5.3 heads from '01-'06. So I'm hoping thats that's not the case. I have 144k miles on it. also my second problem is oil gets really low to with no leak visible, I changed the oil about less than a month ago and already its almost 2.5 quarts low. please let me know what you think. also my check engine light, and ((brake)) light is on. If you have any questions please feel free to ask Thank you.