My 04 Grand Cherokee has 150k miles and has had nothing but conventional oil its whole life. When its cold, sometimes i have a lazy lifter, seems it takes a few seconds to pump up because its noisey as hell. A few people suggested that i switch to synthetic oil and it might fix the problem. Any input on this? thanks.
:lol:
Mobil 1 will cause seal leaks, unless you get the European blend, which I believe only comes in 0w30.
Kind of a tough situation.
Lighter weight oils or synthetic oils will get up to the top of the engine quicker and therefore it will take less time for the oil to arrive and lubricate things. BUT, you could also possibly find new oil leaks by switching to a synthetic oil, and obviously a heavier weight oil will be better for a high mileage tired motor.
shes not even that… thats what makes it so awesome my friend… stick with me and i will teach you the shady ways 
how do you tell its european blend
Mobil puts it on the bottle. It has more zinc and phosphorous if I remember correctly, increasing shear. They had to call it Euro blend to get around US emission standards.
My DD has 140K, I run 10W-30 Synthetic Max life and a quart of lucas oil, it honestly runs as smooth as a brand new car, I’d go for it.