What oil weight is recommended?

[Sincoln]

What oil weight are you guys running in your fwd 4.6L DOHC? Pretty sure I ran 5w30 synthetic in my Mark VIII, but I ran that car harder. Is that the normal weight for the 99' Continental? Or are you guys running 5w 20? 85k miles atm. And it's 6 quarts with filter change? I'll only run full synthetic.

 

[Firebrian]

I run 5w-30 in my 2002 Conti. For the 1st 45K miles I ran 5w-20 per the owner's manual and fill cap labeling. Then I discovered the oil back speccing for CAFE that Ford did back in 2000/2001. It then occurred to me that I ran 5w-30 on my 1997 Conti for over 230K miles without issues or heavy oil usage (5w-30 was the spec). So after a little more research on line and at Bitog, I went back to 5w-30 (currently prefer Pennz Plat, QSUD). No doubt there are millions of engines that did not fail early on 5w-20. But, I want the optimum oil for my engine's life and minimal maintenance, not an extra 0.1 to 0.9 mpg. If that gets my engine an extra 20K miles (3 yrs for me) that's worth it. My 1997 Conti went those 230K miles without removing the timing chain cover. That's what I want for my 2002.

Since the 4.6L was designed by Ford engineers in the 1990's to run on 5w-30, that's what I go by. The Conti engine didn't change much at all from 1996-2002. And if you live in warmer climates, even more reason to run a 30 grade. Other countries spec 30/40 grades for the 4.6L, such as in Europe, Australia, Carribean, southeast Asia, etc.

Oil Viscosity for DOHC Ford - Ford Mustang Forums : Corral.net Mustang Forum

I know some people that run 0/5w-40 oil successfully for over 100,000 miles, though typically in Florida-like climates. If I lived in a region with brutally cold winters like North Dakota, I might be inclined to run the 5w-20 if the car saw mostly short trips. Since my winters are typically 15 - 40 deg F, the 30 grade is fine. In that link above I'd not buy into all what Dr. Haas discusses as that has been completely revamped over at Bitog's Motor Oil University in 2016 to take advantage of new research and better oils over the past 10-15 yrs. Likewise 0w-XX isn't necessarily the best oil for any cold start because it's thinnest. If you're at an ambient temp where a 5w or 10w (most of the USA, most of the year) flows adequately on startup (ie CCS and MRV meet ambient specs) then the thicker oil might actually provide better protection while oil flow is being established.

6 quarts per oil change. Though sometimes it seems mine takes 6.25-6.5 qts. Using a Fram Ultra Guard XG2 synthetic filter at $6 each (rated for 15K+ miles) that I change every other oil change (8K miles per year).

 

[Sincoln]

Your thinking basically mirrors mine Brian. I've noticed cars (Subaru for example) going to factory-spec'd thinner oils are having spun bearings, etc. while still in the warranty phase i.e. 11k miles and an engine that historically never had issues in the past, all of a sudden in having them on thinner oils. Think they are going to thinner oils as a sneaky way to get around emissions or buy time as they find better alternatives.

Anyhow, got some 5w 30 Valvoline full synthetic. My Mark VIII was run on it as well.

 

[Mike Pizzuto]

Conventional Motor Oil, 5w-30 In the summer and 10w-30 in the winter, 1998 Lincoln Mark viii

 

[Firebrian]

Conventional Motor Oil, 5w-30 In the summer and 10w-30 in the winter, 1998 Lincoln Mark viii

I assume you meant 10w-30 summer and 5w-30 winter? If not, I'd be interested in your reasoning. I just picked up a couple jugs of QS Defy synblend 10w-30 SN for $6.95 at AAP (net $1.95 after rebate) that I intend to try out next summer.

 

[Svets96]

I went last year to the dealer to get the oil changed real quick, because I was in a hurry. As stated above they run 20W. From now on I will run 30W like its suppose to. Next year I'll swap it out.

 

[Mike Pizzuto]

I assume you meant 10w-30 summer and 5w-30 winter? If not, I'd be interested in your reasoning. I just picked up a couple jugs of QS Defy synblend 10w-30 SN for $6.95 at AAP (net $1.95 after rebate) that I intend to try out next summer.

5-30 is thinner than 10-30 which I feel the thinner runs better in the summer and 10-30 being thicker runs better in winter. May just stick to 5w-30 all around however. Mine has been running a lot better with 5-30 and 93 oct gas. That's just my personal preference.

 

[Firebrian]

5-30 is thinner than 10-30 which I feel the thinner runs better in the summer and 10-30 being thicker runs better in winter. May just stick to 5w-30 all around however. Mine has been running a lot better with 5-30 and 93 oct gas. That's just my personal preference.

Once those 2 grade oils are at operating temp of approx 180 deg F+ oil temp, they behave essentially identically in viscosity, as both are 30 grades. It's only during the first few minutes of warmup phase where one can say the 5w oil is "thinner." If being too thin for winter startup is a concern, the 5w is even thinner in the summer start ups. So I'm not sure I understand the reasoning for 10w in winter and 5w for summer.

Fwiw, when I checked graphs on viscosity vs. temp for M1 5w-30 vs. M1 0w-40, the 5w actually shows a lower viscosity than the 0w in the ambient temp range of approx 40-100 deg F...the range I most often start my "other" car. No doubt that at -40/-35 deg C of F, the 0w is thinner....though not necessarily throughout the entire -40C to +50C temp range. But, since I wanted the high calcium/no magnesium add pack that 0w-40 M1 offers as well as the higher HTHS of 3.6, I switched from the 5w-30 (low calcium, high mg, HTHS 3.1).

 

[Mike Pizzuto]

Once those 2 grade oils are at operating temp of approx 180 deg F+ oil temp, they behave essentially identically in viscosity, as both are 30 grades. It's only during the first few minutes of warmup phase where one can say the 5w oil is "thinner." If being too thin for winter startup is a concern, the 5w is even thinner in the summer start ups. So I'm not sure I understand the reasoning for 10w in winter and 5w insummer.

Fwiw, when I checked graphs on viscosity vs. temp for M1 5w-30 vs. M1 0w-40, the 5w actually shows a lower viscosity than the 0w in the ambient temp range of approx 40-100 deg F...the range I most often start my "other" car. No doubt that at -40/-35 deg C of F, the 0w is thinner....though not necessarily throughout the entire -40C to +50C temp range. But, since I wanted the high calcium/no magnesium add pack that 0w-40 M1 offers as well as the higher HTHS of 3.6, I switched from the 5w-30 (low calcium, high mg, HTHS 3.1).

Just my personal preference is all it's recommended for 5w-30 generally