Have a 97 merc sable with the 3.0 Standard engine. Which Oil pump is in there I have seen the one with the gears and there is one that is separate. when I look at AutoZone with my engine it only shows the one that is separate not gear driven then when I put the dohc one in it shows the gear driven one. now when I go to advanced it shows both. So any help on which I need will be helpful I have the Haynes manual it just shows the gear driven pump.

 

Found the difference, 3.0L standard engine has the basic pump the 24V dohc has the Gear Pump. Sadly Haynes manual does not show the difference. hope this helps any one else