Recommended oil for late 90s Mustang

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Aug 27, 2003
A guy on another board I frequent is asking about what synthetic oil would be best in his Mustang. Its between a 96 and 98 (I'm not exactly sure of the year)with the 4.6L and he runs nitrous oxide on it quite a bit. Based on what I've learned being on these forums I recommended he look for an ACEA A3 rated oil (ruling out Mobil1 10w30 which was what he was thinking about using) in a Xw40 weight. Anyone have any better recommendations or is this what most of you would recommend.
My recommendation would be redline 5w30 or 10w30 since these oils are thick like a 40wt and are made for racing.
The 4.6 needs an oil that can get to the cams quick. It also adjust the tension on the timing chains via the oil pressure. A thick oil will increase the tension on the chains, failing them quickly. Same with an oil that is to thin and can't develope the required pressure. A good 5w-30 synthetic is perfect. Thickest I would go is maybe 0w-40 M1. Rumor has it that the new 20wts are causing permature timing chain failure.
Having owned a 2001 Mustang GT up until two months ago I can tell you from experience that these motors like thiner oil. Mine seemed to prefer Amsoil 5w20 or 5w30. Most guys running superchargers or nitrous still don't run anything thicker than a 5w30. The 4.6 is a close tolerance motor with high oil presure, so it does not like heavier, 40 wt oils.
I disagree. I owned a 97 Cobra Convertible. Used M-1 5-30 since the first km ie. new. Worked fine...had consumption issues even trying to go with 5k intervals...about 1L. So my conclusions would be to start with M-1 5-30 or 10-30 and go up from there to eliminate/diminish consumption with 5-10k mi. intervals. As a side note, EVERY engine these days is an OHC (except GM). In fact it seems like the opposite is true...that OHC's could use a higher viscosity due to their higher revving capabilities and hence, allowing potentially for greater consumption vs. pushrod (low rpm - high power) type Euro and Jap. engines vs. GM. However, we've seen LS1's benefitting from a higher visc. than 30 as well...
Don't rule out an oil bc it's not A3 rated. . Like I said many times, Dodge Vipers, Corvettes and other great cars use Mobil 1 30wt oils. I don't see them having any engine problems.. Add a qt. of 15w-50 to the 10w-30 to bump it up if you want. Or give Amsoil a try if you want to order the oil. I'd prefer an A3 rated oil but we've seen others do well that are not. [ November 20, 2003, 08:09 PM: Message edited by: buster ]
Originally posted by buster: Don't rule out an oil bc it's not A3 rated. . Like I said many times, Dodge Vipers, Corvettes and other great cars use Mobil 1 30wt oils. I don't see them having any engine problems..
At the same time, how many Vipers have you seen with over 100,000 miles on them?
Dr T, I am not sure why you had consumption issues with 5w30. I am very much not a fan of Mobil 1, so I am inclined to blame it on the oil more than the viscosity. My Mustang had 27,000 HARD miles on it when I traded it for my F250, it never used a drop with amsoil 5w20 at 5,000 mile intervals or with amsoil 5w30 at 8,000 mile intervals. My 96 crown vic with 232,000 miles uses very little to no oil between 3k changes with motorcraft 5w30. However I have a buddy with a Grand Marquies 4.6 that always ran 10w40 and his uses about a quart between changes at 150,000 miles.
Here I am. I have had no problems with Havoline 10w30, changing it every 2500mi for 3yrs and 50k mi, spraying 175hp often. I would like to switch to synthetic for the lower temps and better protection, but I don't know which to get or why. I would like an oil that protects the 4.6L (1996) very well while juiced. Any recommendations? Mobil1 10w40? Thanks!
Posted by Nitrousstang on another forum:
Thanks for all the info man, very helpful. Clear one thing up for me though... I do understand that 0 is going to pump more freely than 15, just like water will pump more freely than the thick oil will... however it will not reduce friction as much because it is so thin... correct?
Can one of you guys here help me explain to him why this is incorrect. This has been my explanation to him so far:
A 0wX oil will lube better on startup because of its ability to pump easier at lower temps... Remember no matter how thin a 0wX oil is at startup, when its at operating temp its even thinner (which goes for all oils). So after setting overnight in 0*C weather a 0w30 (or 40) will still be thicker at startup than when at operating temp of 100*C. You've got things *** backwards. A 10wX or 15wX would provide worse lubrication at startup because it doesn't pump/flow as freely as a 0wX oil. You need to ignore the zero in a 0wX oil for what you are talking about. The 0, 5, 10, and 15 are best dealt with if you think of them as "imaginary" numbers. Or something more along the lines of best, very good, okay, and not so good (respectively) as an indication of pumpability/flow at low temps. A 0w30 is still thicker at 0*C than a straight 30wt is at 100*C.
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