Why not just swap out 4 and 3... cyl. 4 is the only one that starves. so do 3 and 4, or even 2 as well, so you will take care of most of the problem... just seems that #1 cyl. is a night mare... 1 is by the oil pump, so it gets the most pressure, thus why 4, being the farthest away, gets the least pressure and causes premature wear... i think i may try swapping only 2, 3, 4, and not 1.

discuss...

 

Honestly, if you're going to go through the trouble of swapping out oil jet bolts, might as well do it right and do all four cyliders. #1 is hard to get to but not impossible. You already have the oil pan out, just spend a little extra time and get all 4 done.

 

swap out all 4..now what about the oil pump being revised as well 04 and up? Higher pressure? There has been concern because 03 with the new oil jets have had failures as well but none 04+

 

Its not all that bad to change #1 . I used a long 1/4 inch extension with a swivel socket on the end . If youre going to do it then do it right !

 

Agree, it's not hard, JUST DO IT!

 

if you are going to drop the pan and go through the other 3 bolts, then just get a flex or wobble joint and do #1 as well. Enough people have done it with 0 issues that it is worth at least trying. With the exception of just a few (who stripped threads or other) the worst case is that you struggle with it for 30 min. What's 30 min under your car compared to knowing you completed the entire job correctly? If you are not worried enough to do #1, then why bother doing the other bolts? Unless you track a lot your car will be fine, if you do, do all the bolts.

 

There was an oil pump revision for the AP1?

 

not a revision just a different part number for the 04+ oil pump I think it has yet to be decided weather it flows more or not.
I have been thinking about the oil bolt hole area. The object is to get more oil through the bolt and to the bottom of the piston, well wouldn't just going from a 10w30 (thicker) to a 5w30(thinner) have somewhat the same effect since the thinner the oil the more is going to flow through the two holes, therefore increasing the amount of oil hitting the bottom of the piston?

 

Might be more flow through the jet, but will usually be under less pressure since it also flows around the pump more.

The first number usually refers to the cold properties of the oil. 10w30 vs 5w30 are the same at engine temp. (Someone correct me on this, but that was my understanding)

 

The visc cp is generally in the same range at operating temp. So, no difference.