Old-Raptor-guy
FRF Addict
It has taken me awhile to sit down and put this together.
Of course Ford has a some financial incentive to recommend an oil that will give a reasonable life expectancy. But alas, I don't believe ANY manufacture has much incentive to recommend the "perfect oil".
The following is my philosophy after pushing almost 4 decades of experience and research, You can follow it, learn from it, ignore it, create your own ideas.
I will start with philosophy #1
Every business and I mean EVERY business has to answer to 3 entities.
The Government (local to federal)
The stock holders
The customer
In that order, personally everyone should remember that at all times.
Side note: prior to the 1980's the order was actually Government, customer, stock holders. In the 1980's (maybe late 70's) some big stock holders in a couple companies sued stating the their interests where not being met, that the company had a duty to maximize profits over almost everything else. They won and it changed business forever.
Anyway
The government requires a lot from manufactures. One of those is CAFE (Corporate Average Fuel Economy) Manufactures are always trying to find ways to meet this requirement. One way they do this is with "lighter" or "thinner" fluids.
Thinner fluids requires less HP to move which means less fuel.
But there is no free lunch and always trade offs.
I am going to go back a few decades to the mid 1980s. I worked at a Ford dealer. There were new technologies coming out and a couple that blew the older techs minds (I was young back then and didn't really know a difference) was transfer cases and manual transmissions that "required" automatic transmission fluid Instead of the really thick gear lube (75w-90). This was done 100% for fuel mileage and for no other reason.
The gearboxes were obviously designed for thinner fluids, I would never tell anyone to put gear lube in them. But at one point I saw a memo (I wish I still had it) and it stated the following (not quoted word for word). Also FYI ATF is around a 5w-20 oil I believe (newer ATF even thinner)
Ford had asked that New Process (company that makes transfer cases) and ZF (made the 5 speed transmission in the F250-350, became a 6 speed in 1999) to investigate the use of ATF in their respective gear boxes even though both had originally spec-ed 5w-30 engine oil to Ford.
The memo stated that New Process found that the average life of their transfer cases would drop around 50,000 miles from around 200,000 to around 150,000 miles
ZF stated the average life of their manual transmissions would drop around 75,000 miles from 250,000 to around 175,000
Both these numbers were acceptable to the industry (everyone changed to ATF not just Ford) also the 5w-30 engine oil spec from the manufacture was never released to the public, it was all internal testing.
Guess what fluid is in my 2002 ZF 6 speed 4x4 PSD.
Now on to engine oil. All modern engines have pretty much the same oil clearance specs. A modern engine is really any "new" engine designed since around 1990. The clearance spec is right around .002 of an inch. Any less and there is not really any room for oil.
I will stick with Ford products but this all applies to every manufacture.
If the oil clearance specs are all the same, then WHY different oil recommendations???
Lets take a 2018 F150 with a 3.3 non-ecoboost engine, and a 2018 F150 Raptor with 3.5 HO ecoboost engine. They have the same oil clearance specs on the crankshaft bearings and connecting rod bearings. AND in fact the part numbers for the crank bearings and rod bearings are EXACTLY the same.
So why would the 3.3 engine "require" 5W-20 oil and the 3.5 ecoboost engine "require" 5W-30. This example is across the board between non-ecoboost engines and their turboed counter parts.
Another one is the 3.5L Taurus and the 3.5L eco-boost SHO. Those 2 engines share over 90% of their parts, with the differences being small insignificant (to the lubrication system) like the intake manifold. Same Thing, non turbo gets 5W-20 and turboed gets 5W-30.
This tells me that Ford knows that 5W-20 oil does NOT protect/work as well as they would lead the general public to believe. Obviously turbos add heat and 20 Weight oil can not handle it. So if all things being equal 5W-30 would protect an non-turboed engine even better.
What it all boils down to is heat. Lighter oils burn off/ vaporize and break down faster.
I could go on and on and on. But for the most part there is a ton of evidence that all manufactures recommend the lightest possible oil so they can meat CAFE requirements and longevity is a second or third consideration. It goes to reason if that is the case (which I believe it is) then 5w-40 would be a better oil for turbo-ed engine. Which is also ironic because turbo diesel engines have required a 40 weight oil since forever.
Which leads to another example. the 6.7 Ford PSD. In the owners manual, and even on the oil cap it says 10W-30 oil unless any of the following are present. bio-fuel usage, extreme heat, extreme cold, dusty conditions, towing. then 5W-40 oil is required. This tells me Ford knows 5W-40 oil protects better but the 10W-30 gets better MPG for Ford's CAFE rating.
When we talk about better MPG we are only talking .1-.2ish which doesn't make much if any difference to the consumer but averaged over 500,000 units and it does make a difference to Ford.
Lets talk about what the numbers actually mean. The first number with the "W" is the weight/viscosity of the oil cold, measured at freezing I believe. You want the lowest number here. This doesn't mean the oil is super thin per-se it means the oil doesn't thicken up as much. There are a bunch of YouTube videos about this. You want oil to flow as fast as possible to all moving parts.
Before Youtube in the 1990's I saw a study of different oils flow time. The engine used was push rod V8, 5.8L (351) or 7.5L(460) Ford i believe. On these engines the rocker arms are the last things to get oil. Test was done at 32 degrees, oils used were 15W-40, 10W-30, 5W-30. On cold start up the time for oil to reach the rocker arms was measured.
15W-40 - 185 seconds (yes 3 mins)
10W-30 - 45 seconds
5W-30 - 15 seconds
You might ask, why in the Eph is/was 15W-40 the recommended oil for diesels forever (still is I believe in Cummins and D-max) that is because they needed the 40 weight rating to handle the heat and and 10W-40 conventional oil wasn't really possible (yes it was produced for 4ish years but the polymer chains required for a "points" spread that big broke down rather quickly) . The biggest possible "points" spread with conventional oil is 25 points. Anything more than that has to be a synthetic oil.
The second number is the weight/viscosity of the oil at 200 degrees. Again the doesn't mean the oil doesn't get thinner, it just doesn't get as thin as a 5 or 10 weight oil would at 200 degrees.
let's not even get into Maintenance issues, I see vehicles daily that go 7,500 miles per oil change and let me tell you if you value your vehicle then that is retarded. 5000 MAX and that is for a vehicle that is not pushed hard, commuter/grocery getter car. If you push your vehicle by towing/racing etc.. I highly recommend more frequent oil changes.
Which leads me to a question. Why today am I seeing more internally lubricated part failures today than I was 30 years ago. Yes we had oil leaks like no-tomorrow but internal parts failures pretty rare.
The 4.6 "modular" engine came out in 1990 with chain driven over head cams, the 5.4 version in 1996. original oil recommendation was 5W-30. I never saw a "strechted" timing chain in one of these engines until a couple years after the recommended oil was changed to 5W-20 in 2002 (was done to meet CAFE requirements, not one single part changed inside the engine). I have seen dozens of pre-2001 engines go over 300k and the Crown-Vic is almost famous (top-gear for example) of going to 400K with-out much effort.
What about the summer heat in AZ, how can they recommend a lighter oil for cold temps but not a heavier oil for hot temps. Ah that pesky CAFE rating again.
Personally the perfect oil if it existed would be a 0W-50 ( it probably does exist but is a lot of $$$)
I believe the GT and the GT500 (possibly the GT350) recommend a 50 weight oil, and if it was hot and I was going to baja the shit out of my raptor for hours I would want a 50 weight oil to handle the heat.
But I normally run 5W-40 (diesel) oil in all my vehicles (7.3 PSD, 3.0 duratech, 3.5 ecoboost SHO and now 3.5 ecoboost HO)(oh and 3.2 atx SHO but that one is gone). They have been taking Zinc out of Diesel oil the last decade or so but it still has more than "gas" oil.
Zinc is an excellent anti-wear additive and if you don't know about it look up (high zinc flat tappet break in oil). Most oils have the bare minimum of zinc, as it is believed but not proven that zinc can damage Catalytic Converters. My answer to this is two fold.
1: If my engine uses no measurable amount of oil how is zinc getting into the Catalytic Converter
2: I would rather by a Cat than an engine.
With just around 550,000 miles of 5W-40 usage in my fleet I have never bought a cat for any of my vehicles ever. I also have never had any internal engine problems. I am about ready to do the 3.5 SHO water pump, but that is a maintenance reason as if you know when they go out they dump all the coolant into the oil and that vehicle is right at the mileage I see then fail at.
I will tag @FordTechOne into this, in case he has different thoughts.
Next we will talk about life time transmission fluid and how retarded that is....................................
Last edited:
