Dineau

I know our manual suggest that we use 5W20 or 5W30 if you have a V6 but I have a little question for you folks that are better at this than me.

If I only use my car in the summer, do I really need to go with 5Wxx type oil ?

Can I go with 10Wxx instead ?

My understanding was that the 5Wxx type was more suited for cold climate and I remember in the old days my dad putting 5W30 in the winter and 20W30 in the summer in his Camaro.

What do you think ?

Any issues or a good thing to go 10W in the summer ?

Thanks for your inputs

v6tungsten

Just use 5W30. Im in Texas and use that all year. there's no reason to use 10W30 as both will be 30 weight when warm.

hammeron

i've been using 5w-30, because costco sells
the 12 qt packs

red pony

( 1 ) Use 5 W 20 for the sake of the warranty issue . ( 2 ) Use the Motorcraft oil filter exclusively also, not only for the warranty, but because it's the highest quality and it's made for the car . ( 3 ) Technology for oil in the last few years has changed for the better due to additive packages being improved , plus the concept of synthetic and synthetic blends have vastly improved the anti-wear characteristics of oil today . I used to be an avid 20W50 advocate ( I still am when it comes to cast iron V8's with high mileage ) but , with today's high-tech metalurgy , synthetic blends are better matched to the aluminum engines of today . In fact , if you run 20W50 in a 4.6 3V , you may damage the top end of the motor due to the oil not getting there quick enough upon cold start-up . Besides, synthetic and synthetic blends will stick to engine parts long after thicker oils run off ( and when I say run off , I mean run off down to nothing ) . The reason it doesn't run off so fast is its larger , more uniform molecular structure . Just stick to 5W20 in a 4.6 V8 and 5W30 in a 4.0 V6 Mustang . Stay with synthetic or synthetic blends .

gt/cs08

Good advice !!!!!!!!!!!

cal66

Great~what about the interval between oil changes with weekend use only? No track racing. Every three months or every 3-5,000miles? Does the use of synthetic oil have any effect on the warranty? Thanks...

poldrv

I always go with what the manufacturer recommends. 5w30w for me, all year round.

theedge67

If you are only driving the car on the weekend, you will not rack up many miles. That doesn't mean you should change the oil every 2 years, when you finally rack up 5K miles, but it also doesn't mean to change it every 3 months either. It all depends on your driving style, how many miles per year you are actually putting on, and most importantly...how many miles you are putting on the car per driving event.

If you drive 2 miles to work per day, 5 days a week...that = 20 miles round trip per week.

If you drive 20 miles in a weekend, and that is all you drive, that is much MUCH easier on your oil than those 20 miles/week previously mentioned.

That said, as long as whenever you do drive it on the weekend, you get the oil good and hot and take it for a drive of at least 20 miles each time you start it, go with 5,000 miles or once a year, whichever comes first. If you are using full synthetic oil, stretch that out to 7,500 miles...but keep the 1 year interval. Don't let used motor oil sit in your engine for more than a month because it will seperate and form deposits and sludge on the bottom of the oil pan. Always change the oil BEFORE a long storage.

metroplex

I would stick with the 5W-20 for warranty and fuel economy. The extra protection afforded by a thicker oil isn't going to be noticeable.

Dineau

Thanks for the advise....

I only use Ford oil filters (I even buy the Ford Racing, since the cost is not much higher). As far as oil I use Mobil1 Syntetic.

Th reason for my question on 10W30 is because there's always great specials on 10W30 and 10W20 (like 10$ less) but never on 5W30. So that's why I was wondering wath was the impact, especially that I only drive my car in the summer.

Thanks again for your inputs

Lime GT

5w20 and 5w30 are the prevailing oils in todays cars. The higher grades are probably slow movers thus the sale pricing.

theedge67

If you are only driving the car in the summer, I see no issue with running 10W30. The difference in actual thickness is really not that great anyway, and in the summer the difference will not be enough to matter one bit, in my opinion. I have done quite a bit of research on oils and I would have no issues running 10W30, especially in a V6.

frdfrst

the motor was designed to use 5/20.the clearences are for the 5/20 so they can meet the miles per gallion for ford.i've been told by friends that are mechanics and past ex. to use whats recommened as the above reasons.

bob

Indeed, the engine in the case of the 4.6 3v is designed for 5W20, the lash adjusters for example wont bleed down properly with higher viscosity oils. I would also guess like the 4.6 2v, the cams don't use bearings, they are just cinched down in the saddles, while not as bad as when the cam journals go bad in a viper block (they also dont use cam bearings), wiping out the saddles in a 3v head will probably mean cyliderhead replacement (unless like the viper blocks sombody has figured out a way to adapt cam bearings).

Gearhead

5W-30 is totally fine for either your V6 or your GT engine. Remember that when 5W-20 oil is at operating temperature, it is phenomenally thin (about 50 Saybolt).
Keep in mind this definition of a 5W-20 oil:
It behaves like a 5 weight at 0F
The "W" means "safe for Winter applications"
It behaves like a 20 weight at 212F.
By the viscosity tables, I read the following Viscosities:
a 5 weight oil has a viscosity of about 3,000 Saybolt at 0F
a 20 weight oil has a viscosity of about 50 Saybolt at 212F
a 30 weight oil has a viscosity of about 65 Saybolt at 212F
a 40 weight oil has a viscosity of about 70 Saybolt at 212F
a 50 weight oil has a viscosity of about 95 Saybolt at 212F
So, if your top number is 20, 30, 40, or 50, they are all far thinner than 5 weight at 0F. You won't hurt your engine, and actually would protect it better with a higher second-number oil. These thin second-number oils are all about fuel economy. Note that the new Shelby REQUIRES 5W-50 because of the bearing loads, so you know that the thicker-at-temperature oil will work in engines of this general design.
I run 5W-50 in everything I own, and change at 5,000 mile intervals. Ford sells the oil for about $10 per quart, and Castrol runs about $6.50 or so. Their higher cost is offset by less frequent oil changes and longer engine life.
NEVER run a higher-than 5 weight base oil in these engines, even in the summer. They are too thick at startup, and you could crash a bearing.
The reason that Ford recommends the very thin second number is that they do get better fuel economy (about 0.1 MPG). However, your engine will last longer with a 5W-50. You will have fewer bearing strikes, and less metal content in the oil (not visible shavings, but measurable by oil tests none the less). Finally, the thicker second number gives you double the bearing protection in lugging conditions, where journal speeds are low, and the thicker viscocity will allow your bearings to carry twice the load without crashing.
If you run a standard quality 5W-20, I would recommend changing every 2,000 miles, because the index stabilizer can break down, where the oil can start to behave like a 5W-15 after 2,000 miles, which puts you below minimum bearing requirements. If you run standard quality 5W-30, then you I would recommend changing every 3,000 miles, before your anti-corrosion additives are all absorbed. The higher cost synthetics are safe for 5,000 miles.

theedge67

Excellent post Gearhead, pretty much tells it all right there. I would say that a good quality synthetic is probably good for more than 5K miles in most instances, but it really depends on how you drive. Lots of highway miles and you should be good for at least 7,500 miles on a quality full synthetic. Lots of city miles though and you might want to change it out at 5K to be safe.

RagtopV8

So, Gearhead and theedge67, what would be your opinion of Mobil 1 0w40 in a stock GT motor as opposed to Mobil 1 5w30?

Has anyone here run the Mobil 1 0w40 in the GT? How about the Mobil 1 5w30 Truck and SUV oil?

I'm all for running oils with higher HTHS values than are available with the 20wt oils, but how much is too much?

metroplex

Just use a full synthetic 5W-20 or 5W-30.

Indystang

Are you a chemical engineer?

theedge67

I would not go higher than a 30 weight. 5W30 seemed to work magic in my engine, and I have the oil analysis to prove it. I showed considerably less wear metals in the oil with 5W30 than 5W20 oil.

I think 5-40 oil might be pushing it though, thicker is not ALWAYS better.