I'm new to this board so I'm sorry if this question is old news but what is the deal with 5W20 oil? I have a 2001 F150 with 5.4 and my son has a 2001 Mustang GT. Every oil change we run around looking for a lube place with 5W20 oil. Most either don't carry the oil or they are out. Today I thought I would remedy the problem so I called the local Ford dealer to set an appointment for an oil change on my F150. I asked if they had 5W20 oil and was surprised when he said yes but you don't have to use it. He stated Ford "did that for mileage" but it was o.k. to use 5W30. He also stated 5W20 was more expensive. What is up?

 

I don't know the answers to your questions, but I have noticed the trend to thinner oil. I can't bring myself to put 5w-30 in my truck, especially in summer, so I'm using 10w-30. My mechanic said it won't hurt it. I'd be interested in comments from all the more knowledgable people out there.

 

This has been beaten to death. Use the search and you will find all the answers you seek.

Basically the 5w20 and the 5w30 both use the same base stock but the 5w30 has more viscosity modifiers for hot operation. The 5w20 is only "thinner" at high temperatures, at start up they are both 5w oils. Using 10w oils in an engine designed for 5w will decrease your gas mileage and in some cases may cause oil starvation issues especially at startup. If you live in a hot climate zone 10w may not cause any trouble at all.

Again do a search and you shall be rewarded.

 

I posted the oil tsb a few weeks ago....search my name for it, I think.

Both my ford dlrs said to use it, and older rides can use it too as that is what ford is now recc for just about everything. I am going to go to it because I will not be doing my own oil changes for a while (had to move into a dinky apartment after my divorce, but I still have my truck!) and I will only let a ford dlr touch it.

Ford recc 5w20 for gas better gas mileage although I dont see how it can make a big diff, other than for ford's CAFE numbers.

--karl

 

I will not put 5W20 sewing machine oil in my $24,000 truck......5W30 Amsoil is what I use. 5W20 oil is spec'd by Ford for fuel mileage only.

 

I'll keep using 15w-40 in my 1992 4.9 and we'll see who gets the most miles...

 

That's not fair...........you have the indestructable 300 CID 6.

 

The reason that the 5w-20 is more expensive than 5w-30 is because they don't manufacuturer as much of it right now. As time goes on and if it becomes a popular choice, you will see the price go down, but oil manufacturers produce a lot more 5w-30 and 10w-30 right now. I am not sold on using that light of an oil in my vehicle.