Would be no problem on the 4.6. Many of these motors have seen 15w40 in fleet use. My old mechanic used to think that 20w50 was needed in everything. He maintained a limo/business fleet which was mostly Towncars at the time. Many of them had 300-400k on the thick stuff with no issues. I currently run 15w40 in my '08 Crown Vic w/ the 4.6. If anything, startup noise is less than with 5w20 in my experience. Now if you were in extreme cold environment, different story.
High mile 4.6 Ford - Ok to use heavier oil?
- Thread starter Twisted1
- Start date
Give the QSUP 5W30 a chance. Walmart sells that in 5 quart containers and quarts --- not by the gallon. At that price, it's a no brainer.
I used 10w-30 high mileage in my 4.6 Mustang simply because I didn't have to add any between changes, while with 5w-20, between the leaks and slight consumption, I did.
The oil passages in the mod motors are small and you need those timing chain lash adjusters to pump up as quickly as possible. I have ran Mobil 1 0-40 in my 2V 5.4 without issue, actually did well in it, but it is a "thinner" 40W oil that shears down to a heavy 30W pretty quickly, the 0W aspect seemed to vastly diminish the cold start noises.
Took a few pics of the selection at my local Walmart this morning
Mechanical shear of the VM is highly dependent on engine design. That isn't an issue here, and by far the vast majority of "shear" UOA on here have been due to fuel dilution. The notion that Mobil 1 0W-40 "shears down t a heavy 30W pretty quickly" is often repeated here but always with no supporting evidence (especially for current formulations).
Small passages? How do you know this? And just how big do you think oil molecules are?
I have used 10w30 and 10w40 in engines that spec 5w30, with no ill effects that I could tell. These engines continued to run strong for a very long time. They had at least 150k miles at the time of viscosity change. Temps here range 25F winter to 110F summer. I believe 10w oils are OK for cold starts down to 0F, someone correct me if wrong.
25° winter in Cali? Are you closer to Tahoe?
Sacramento. 25F is the coldest winter night I have seen in the last few years... pretty rare, but it does happen.
More typical winter nights are 30-35F but in the context of this conversation I don't think it matters all that much.
There's no basis for increasing the viscosity. There's also no harm in doing it either aside from a miniscule change in fuel efficiency (if any) and a tad higher operating oil temp (from increased hydrodynamic friction). If the engine has clearanced itself excessively to the point of warranting a viscosity increase, something is already terribly wrong. Contrary to popular belief, the operating oil temp doesn't vary significant enough with ambient temperature to warrant a change in oil grade. The oil simply doesn't care as much if it's 20°F or 100°F outside when it's surrounded by 200°F coolant, passing through 275°F bearings, and splashing on 450°F cylinder walls. Load has a much more significant impact than ambient temp on the oil's operating temp.
I don't like the idea of 10W-40 as it's an oddball grade these days. Conventional 40 grades are usually 15W-40, synthetic 40 grades are usually 5W/0W-40, and 10W-40 is just this oddball in the middle. As such, they tend to not get very much attention, much less R&D. The exception is a specialty oil requested in that specific grade such as HPL's No VII Euro 10W-40. The only reason that grade is still available is because it's still selling sufficiently enough to people who still think it's 1975. The majors on the store shelves are in a race to the bottom. They're going to formulate the oil as cheap as they can possibly can for a given standard as that gives them the opportunity to underprice a competitor at the same or better profit margin. The wider spread grades actually tend to be better at high operating temps and loads as it forces them to use better quality base oils and VII to meet the spread. With that better quality comes lower volatility, better shear stability, and more oxidation resistance. This applies to common store brands, not so much boutique brands.
If you insist on using a 40 grade, I would recommend Mobil 1 FS Euro 0W-40 as it's the best bang for the buck off the store shelves. It's better in pretty much every parameter compared to that 10W-40.
My Tahoe has ~286k miles and still on 5W-30 oil at 15-20k mile intervals. My Nissan hardbody has >480k miles and still on 5W-30.
I don't like the idea of 10W-40 as it's an oddball grade these days. Conventional 40 grades are usually 15W-40, synthetic 40 grades are usually 5W/0W-40, and 10W-40 is just this oddball in the middle. As such, they tend to not get very much attention, much less R&D. The exception is a specialty oil requested in that specific grade such as HPL's No VII Euro 10W-40. The only reason that grade is still available is because it's still selling sufficiently enough to people who still think it's 1975. The majors on the store shelves are in a race to the bottom. They're going to formulate the oil as cheap as they can possibly can for a given standard as that gives them the opportunity to underprice a competitor at the same or better profit margin. The wider spread grades actually tend to be better at high operating temps and loads as it forces them to use better quality base oils and VII to meet the spread. With that better quality comes lower volatility, better shear stability, and more oxidation resistance. This applies to common store brands, not so much boutique brands.
If you insist on using a 40 grade, I would recommend Mobil 1 FS Euro 0W-40 as it's the best bang for the buck off the store shelves. It's better in pretty much every parameter compared to that 10W-40.
My Tahoe has ~286k miles and still on 5W-30 oil at 15-20k mile intervals. My Nissan hardbody has >480k miles and still on 5W-30.
Thank you for the explanation and advice on the oddball oil grade… Are you using Mobil 1 in your Tahoe? Also, is the Mobil 1 FS 0w40 a thinner oil vs. something like Castrol of the same flavor?
I’ve never had one out, but I’ve read that the orifice is around 1 mm. There’s plenty of Euro high HTHS 5W30 oils around, that’s what I would use on mine if 5W20 was ever not good enough.
So run a 5w50… Motorcraft has one, Mobil has one, HPL has one… and the HPL has a pour point of like -81F, so there’s no worries in cold weather.
Here are the lab reports for my 4Runner performed at Shell Labs:
SuperTech 10w-40
Equipment Life 280,003 miles
Lubricant Life 5,061 miles
Viscosity 100C cSt 12.9
Pennzoil Euro 5w-40
Equipment Life 285,022 miles
Lubricant Life 5,022 miles
Viscosity 100C cSt 12.6
Still in grade, barely.
SuperTech started with an advertised V of 14.96
Pennzoil started with an advertised V of 12.72
Fuel dilution for both oils <1.0%
I cant read all the posts but I have owned over 30+ panther platform cars and I have safely used 0w-20 up to 10w-30. I highly recommend **NOT** going to a 40w as you can feel it. And you will also loose some MPG. I used german castrol 0w-30 in a 99 CVPI and at first I did not notice why I only got 19 mpg on the flat highway, and admittedly I did not notice the power reduction. When I swtiched back to motorcraft 5w-30 the power and fuel economy was back.
After researching that back in 2006, I found out german castrol of that era was a basically a 40 weight when hot.
After researching that back in 2006, I found out german castrol of that era was a basically a 40 weight when hot.
GC is/was a 30-grade all day long.
dnewton3
Staff member
I have probably (estimated) 600+ UOAs for 4.6L Ford mod motors from just about every application you can imagine. Car; trucks; short trips; long trips; cold areas; warm areas; etc ...
I can say with absolute certainty that the grade of lube won't affect wear rates, etc. (As long as it's a reasonable grade for the application). Especially in 2v form, these engines are fairly well-wearing, and whatever your engine does is unlikely to be affected by the lube choice.
Anything from a 0w-20 to a 10w-40 will work. Conventional or syn doesn't affect wear rates either.
If you want to hedge your bets, use a 5w-30 or 10w-30; the Goldilocks "middle" of all choices.
I can say with absolute certainty that the grade of lube won't affect wear rates, etc. (As long as it's a reasonable grade for the application). Especially in 2v form, these engines are fairly well-wearing, and whatever your engine does is unlikely to be affected by the lube choice.
Anything from a 0w-20 to a 10w-40 will work. Conventional or syn doesn't affect wear rates either.
If you want to hedge your bets, use a 5w-30 or 10w-30; the Goldilocks "middle" of all choices.
I grabbed 2 jugs of QS FS Euro 5W-40. My decision came after reading a lot of UOA’s of that oil on here repeatedly showing that they’re truly a thick 30 weight rather than a true 40 (by a slight margin). I think with the 100°+ summer’s we’ll see this year, it should be perform rather well.
Great choice!
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