: Best oil and spark plugs for the northstar 4.6L

06-26-09, 06:18 PM
I'm sorry if this was posted already I checked a dozen pages and found nothing....anyways I was curious which oil brand is considered to be the best for this engine or is it prefrence. Also which spark plugs are Good I'm looking to replace these in my eldorado. Thanks alob Matt

06-26-09, 07:26 PM
Matt, be sure to go OEM (AC/Delco) on the wires and plugs. I used Rockauto.com and got the set for my 4.6 and have been very pleased for over a year now. As far as oil, just use a good quality 10w-30w viscosity.

06-26-09, 09:04 PM
I was curious which oil brand is considered to be the best for this engine or is it prefrence.Do a search. Too many oil wars have been fought. There is no "best". They all do the same thing. Pick one.

06-27-09, 02:44 AM
As anybody here OEM OEM OEM OEM, as for oil…what-ever commercial impress you the most as long as is the same viscosity as the one called for in the owner’s manual (not some “specialist” mechanic, neighborhood amateur racer, enchanter or guru).
No point to use synthetic if the manual does not call for, is like eating fast food with your inherited silverware, better change the oil sooner (as recommended by manual) than cooking the synthetic for longer.

06-27-09, 09:29 AM

From your other post up in Eldorado, you're looking for the ways to gain a bit of performance and keep things running correctly. Use a set of ACDelco #41-950 Platinum plugs and an AC wire set from www.rockauto.com. (The plugs are way down in the list, so scroll down.) Make very sure the wires are run according to this diagram. (Google "waste spark ignition) Change the air filter to a WIX unit - more area = less restriction. The system is already CAI, but you could carefully open the inlet, before the filter box, and maybe run a 3" - 4" duct to an area behind the lower grille. Search the performance threads and do a good throttlebody cleaning with toothbrush, rags, and TB cleaner (NOT choke cleaner). As posted, use a good 10W-30 oil from whoever you like/prefer. Use a WIX or NAPA Gold oil filter. Run your tires at 33 psi COLD, and torque the lug nuts to 100 ft/lb in a star sequence. Check all the vacuum lines which come off the throttlebody top and sides, and check the PCV line which comes from the rear cam cover to the intake manifold. Keep it clean and polished. Again, go up and read the entire Cadillac Technical Archive, up in the black bar ^^^.

06-28-09, 12:14 PM
Thanks guys I am using the ac delco wires already.as for the intake idea I'm going to look into that and cleaning my throttle body thanks alot guys