I have read that Ford now recommends 5W20 oil for most applications that previously specified 5W30 oil.
My questions are this...
Can the synthetic or synth blend oils be mixed with standard dino oil?

Would there be any issues with the oil or the engine if I were to add a quart of 5W30 to top off when I had 5W20 in the motor?

I know it sounds like a newb question, but I just know at some point I'll forget that I'm using 5W20 and pour a bottle of 5W30 in there.....

Are there any concerns with changing to 5W20 with a fair amount of miles on the motor?
I have a 97 4.6 with about 83K on it.

 

you got two questions there. one was can you mix synthetic with regular oil, and the other is can you mix 5w20 with 5w30. the short answer to both is yes. however, it is normally suggested to not mix different brands as they might have different addative packages. Yes you can mix 5w20 with 5w30 or 10w30 oil. Second it is best to stick with one brand, Mobil, Castroil, etc, but mixing them will not be drastically detrimental. Last, yes you can mix synthetic oils with standard oils, but again, this is normally not a recommended thing to do. It will not damage the motor, just not recommended. NOrmally picking a brand and sticking with it is a good idea. If you have to add a different quart from time to time, that is no real big problem.

 

Well, actually there were 3 questions there.
I started out with one question and as I was typing, the others just hatched.

I usually avoid mixing brands, but I have no brand loyalty other than sticking with a major brand name oil.
I don't use synthetic mainly due to cost. I don't like the idea of leaving oil in the the motor that long anyways. If I have to change the filter, I'm gonna change the oil while I'm under there too.

What prompted all this was that today I was at Wallymart to get some stuff and I decided that I'd get oil for the truck since it'll be due for a change in about a week.

I was checking the prices on the 5Qt jugs and they had Havoline 5W30 for $12. The Motorcraft 5W20 was $12.50 for the 5Qt jug. Now here's the rub...
Since you need 6 qts for a change, you have to get another qt to go with the jug. Wallymart with thier wonderful pricing policies had the single qts of the Havoline for like $3.97, but the single qts of Motorcraft were a dollar cheaper!

I was gonna get the 5qt Havoline and a couple qts of the Motorcraft syn-blend since the had the Motorcraft singles in 5W30 and 5W20, but that would be mixing brands. That was what had me thinking about mixing syn and dino. I really didn't think of the fact that the motorcraft is already a syn-dino blend....duh!

Since the Ford TSB recommends 5W20 for use in some applications that previously spec'd 5W30, and the wife's Windstar uses 5W20 anyway, I was going to make the switch. I'm just a little concerned about going to the lighter oil in a motor with 80K+ miles on it.

As for mixing the grades, I'm sure I'll forget at some point......

 

Don't be concerned with the lighter oil. It only makes sense to use a heavier oil with an engine that is actually worn. And even then, it doesn't entirely work out. The bearings really don't wear enough to justify changing an oil, the only thing that really wears is the rings, and with them, a lighter oil with strong surface tension is still better than a heavy oil.

 

I would have virtually no concern about mixing weights, maybe just a bit of concern on brands but I don't think there is even a problem with that. There are people on bobistheoilguy.com who have mixed 5 or 6 different oil types and brands and after a bunch of miles, had an oil analysis done and everything was excellent.

My '02 E150 with 4.6 has run very well with 5W20 since new; it got Motorcraft for its whole life until a couple of changes ago when I switched to Quaker State Torquepower full syn (5W20) because I got 24 quarts for 99 cents each... I'll probably go back to the Motorcraft when I've used up the cheapo full synthetic, but I am running the full syn out to 6-7k miles whereas I would change the Motorcraft out at 3-4k miles.

We had a '98 Sable with a Duratec 3.0 motor; this was originally specced for 5W30, and later in its life (close to 100k miles on the car) we ran a couple changes of 5W20 in it when we took it to the dealer and that was all they were using...

My perception is that the Duratec burned off a *little* more of the 5W20 than it did the 5W30--maybe a quart in 3000 miles whereas with the 5W30 it was about half that. Nothing I'd worry about, but in the summertime especially I felt a bit better using 5W30 in that engine. Actually, in the summertime, I consciously topped off the 5W20 in that engine with some 10W40 that I had around for our BMW's when it was a half quart low....

George

 

Weird how they say go from 5w30 to 5w20

 

Not really. That’s the CAFE brownie point rabbit hole automakers go through in the US.

The cooler part is where they mention that 5w-30 is acceptable when towing heavy.

But, dropping 5w-30 in at the factory is more expensive and hits them with CAFE taxes.

It is what it is.

 

I use Valvoline VR-1 Straight 40w ! In my opinion anything less is worthless in hot weather, The "on the shelf oil" is too thin !

 

Yes you can mismatch the oils and nothing will happen, but it would be cheaper and easier if you just bought 2 5qt jugs that way you can have extra for your next oil change or if you burn some.

 

I use Valvoline VR-1 Straight 40w ! In my opinion anything less is worthless in hot weather, The "on the shelf oil" is too thin

..... that might work in southern Florida or Texas, but is a BAD idea in general.. Especially in northern States.

 

VR-1 is also a high zinc oil. Not exactly good for catalytic convertors.

 

I run 10W30 Full Synthetic. In my opinion, 5W20 & 5W30 are great for the manufacturer to meet their CAFE rating AND to have your motor wear out just a little quicker (they only warranty it for 5 years anyway). As for a filter, I use only WIX filters in my F-150 (ie - oil, air, fuel).

 

I wonder which will die first; the engine or the cats?

 

I've always run Motocraft 5W-20 in my 2011 F-150 5.0L V8 and I haven't had a single issue doing such. I live in west Texas and our climate 85% of the time is hot and dry. Summers range from 85 to 110 degrees, winters are ''usually'' between 45 and 75 degrees though we do have a few oddball days where we may see below freezing for a week at a time or so. But yeah, in my experience I've always just used what Ford recommended year round and its been a perfectly good experience for me.