please help asap
 

i have a 2000 merc. sable with a 3.0 dohc and it started knocking yesterday when i started it and it sounded like it was coming from under the valve cover so i checked the oil and it was 3 quarts low so i put sum 10w40 in it and started it and it was still knocking so i took off the valve cover and turned it on and number 5 cylinder would knock at around 1000 to 1500 rpm i dnt know how these engines work with that 32 valve stuff but if some one could tell me more less what it could be or tell me how to find out what it is please do

First, lesson learned, check your fluid levels once a week. Second, go to either a trusted garage or I prefer the Ford dealer and have it looked at. Or third, just drive it and wait until something blows up.

In these models the lifters are hydraulic and if you,re oil level was that low 9 times out of 10 that is exactly what it is. The cause is from lack of oil pressure and the lifter was being pressed down with no pressure to pump it back up. It can be a easy fix if you have a mild set of skills. you start by buying a set of lifters for each cylinder you are experiencing the knocking. You should replace both intake and exhaust lifters because there is no way to be sure which one is the cause. Be sure to prime the new lifters in new oil for a few hours first before the installation after you are finished throw a bottle of lucas to thicken up the mix and bam you,re problem is solved. Be sure to look online or in a manual to figure out the best way to remove the rocker arms because I cant remember exactly if they can be removed with the cam in place but I am almost positive you can...