Blend or full?
Moderator
Joined: Jan 2004
Posts: 13,851
Likes: 111
From: SW Va
Well we don't know under what conditions you operate, but if it's really cold where you live & the vehicle sits outside & is started cold, the full synthetic may offer up some advantage in winter.
Looking at Motorcrafts product data sheets, the -30c viscosity on the Motorcraft semi-syn is 5300cp & 4000cp for the syn, so at cold temps there is a 26% difference in the -30c viscosity, with the syn being thinner, so the engine would crank easier with the syn & the oil would flow faster, so if you have an OHC engine, the top end sure would appreciate getting all lubed up quicker on those cold starts & so would the main bearings.
The starter motor & battery would have to work less hard to crank the engine too.
Viscosities at 40c & 100c are about the same & so is flash point, so their hot temp performance is close, thus it seems to me all other things being equal, the syn advantage might be with real cold -30c starts.
Some observations to ponder.
Looking at Motorcrafts product data sheets, the -30c viscosity on the Motorcraft semi-syn is 5300cp & 4000cp for the syn, so at cold temps there is a 26% difference in the -30c viscosity, with the syn being thinner, so the engine would crank easier with the syn & the oil would flow faster, so if you have an OHC engine, the top end sure would appreciate getting all lubed up quicker on those cold starts & so would the main bearings.
The starter motor & battery would have to work less hard to crank the engine too.
Viscosities at 40c & 100c are about the same & so is flash point, so their hot temp performance is close, thus it seems to me all other things being equal, the syn advantage might be with real cold -30c starts.
Some observations to ponder.
Senior User
Joined: Sep 2004
Posts: 218
Likes: 0
From: Douglasville,GA
My truck holds 7 quarts so I used 5 quarts of Motorcraft 5-20 Synthetic Blend and 2 quarts of Full Synthetic Motorcraft 5-20 just to experiment. I've driven 150 miles since the oil change and noticed the engine starts easier. It also seems to get up to speed quicker.
Senior User
Joined: Jan 2006
Posts: 265
Likes: 1
From: Wisconsin
I just switched from dino oil to full syn in rotella brand and I do not notice any difference in how the engine sounds or runs but I am sure it is better in oil circulating on startup and maybe it will be better on fuel.
Senior User
Joined: Jan 2006
Posts: 265
Likes: 1
From: Wisconsin
I guess I should have mentioned that I drive a 03 Super Duty with the 7.3 diesel, and was looking for someway to make starting it easier on these cold wisconsin days.
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Elder User
Joined: Aug 2007
Posts: 503
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From: arizona
The best way to accomplish this would be using a 5w40 syn, which I'm pretty sure is what you used. Syn rotella is 5w40 right?
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Post Fiend
Joined: Jun 2001
Posts: 5,228
Likes: 5
From: Running Springs CA
Right. BTW, every "conventional" oil, except maybe straight 30, today is actually a "blend". There is simply no way to meet the API standards without a synthetic "correction fluid" in the mix.
Logistics Pro
Joined: Jul 2002
Posts: 4,821
Likes: 19
From: South Dakota
I would let the price dictate the choice on gasser oils, but that is my opinion. The noticeable differences in performance are at best extremely small when comparing a synthetic 5w20 to a syn blend 5w20.
Now if we are talking a diesel, that's a whole different ball game when in comes to cold weather performance. I too would reccomend a 5w40 synthetic on a 7.3L PSD. 15w40 conventional is way too thick below 30F for cold starting.
Now if we are talking a diesel, that's a whole different ball game when in comes to cold weather performance. I too would reccomend a 5w40 synthetic on a 7.3L PSD. 15w40 conventional is way too thick below 30F for cold starting.
Post Fiend
Joined: Jul 2005
Posts: 6,127
Likes: 6
Rule of thumb: nearly anything qualifies as a syn blend... don't buy it.
The best name brand dino oil is beaten by the cheapest name brand full synthetic oil.
However, the biggest benefit goes to very cold weather starting (-30 or more F)
2nd biggest benefit goes to very high mileage engines
Most of wear in gas engine comes in first 1 minute before oil pressure is up and oil reaches components.
On Diesel, different game.
Suggest: get the cheapest name brand synth that is the thinnest oil you can run
i.e. syn 5w 20 for my truck....
The best name brand dino oil is beaten by the cheapest name brand full synthetic oil.
However, the biggest benefit goes to very cold weather starting (-30 or more F)
2nd biggest benefit goes to very high mileage engines
Most of wear in gas engine comes in first 1 minute before oil pressure is up and oil reaches components.
On Diesel, different game.
Suggest: get the cheapest name brand synth that is the thinnest oil you can run
i.e. syn 5w 20 for my truck....
Elder User
Joined: Mar 2003
Posts: 616
Likes: 0
From: Farms of Duplin County
Diesel Man03 running the Rotella 5-40 is perfect for your 7.3, it's a great oil and at great price and can be found everywhere.
Senior User
Joined: Dec 2009
Posts: 148
Likes: 0
From: Red Deer AB/Sidney MB
For your 7.3 diesels i would use a 0w40 it has a better border line pumpability which is a better measurement than pour point for winter use.look for API ci-4 it is higher phosphorous/zinc .for 08 or newer look for cj-4 0w40 .Also a group 4 synthetic base oil is best. A group 3 synthetic is usually cheaper, synthetic oil. If it sounds like its too cheap to be synthetic it maybe group #3 syn oil.
Senior User
Joined: Feb 2010
Posts: 226
Likes: 1
From: TX
Oils - DINO vs. Synthetic
All my vehicles picked up about 3 MPG on average, when we went from
DINO to full 100% synthetic oils. They also picked up about 10 HP more,
due to less friction and lower temperatures. The engines run freer and
also stay cleaner inside than DINO oils.
If you are going to use a synthetic, than use a full synthetic, not a blend.
Even all the major names that claim to be full synthetic are really just
blends and not any better than the ones that are semi-synthetic.
With full synthetics, you go 15k miles between oil changes, no problem.
Provided you use a good filter like the Mobil 1 or Royal Purple filter.
Some of the top rated oils are listed below:
Mobil 1
Royal Purple
Redline
Amsoil
Do some research, you will see the truth in what is said here.
Rent-A-Man! lawn & tree
Killeen, TX
DINO to full 100% synthetic oils. They also picked up about 10 HP more,
due to less friction and lower temperatures. The engines run freer and
also stay cleaner inside than DINO oils.
If you are going to use a synthetic, than use a full synthetic, not a blend.
Even all the major names that claim to be full synthetic are really just
blends and not any better than the ones that are semi-synthetic.
With full synthetics, you go 15k miles between oil changes, no problem.
Provided you use a good filter like the Mobil 1 or Royal Purple filter.
Some of the top rated oils are listed below:
Mobil 1
Royal Purple
Redline
Amsoil
Do some research, you will see the truth in what is said here. Rent-A-Man! lawn & tree
Killeen, TX
Elder User
Joined: Jan 2009
Posts: 774
Likes: 1
From: East Tennessee
Where I live, 5W-40 HDEO's are the thinnest start up viscosity you will find. Heard in canada they have 0W-40. Would be nice.
I agree though, RTS 5W-40 would suit your truck nicely, summer and winter.
Think of the people you know that run 15W-40 and 20W-50 in the winter.... Hurts me on the inside thinking of that molasses pumping through the engine at 0F.
I agree though, RTS 5W-40 would suit your truck nicely, summer and winter.
Think of the people you know that run 15W-40 and 20W-50 in the winter.... Hurts me on the inside thinking of that molasses pumping through the engine at 0F.