which oil weight?

I'm original owner of 2004 tacoma with 120,000mi. in Phoenix (hot!). Have always used Valvoline 5W30 oil. Recently advised by dealership to switch to 5W20 for better gas mileage. I have concerns of using this thin oil in the Az. heat. Any suggestions?

 

I would stick with 5w30 since this is what Toyota recommends. It might be a Toyota dealership, but they're not a Toyota engineer. Stick to the manufactures recommended oil weight.

 

+1

Even though the thinner oil probably wont hurt anything...stick with 5w-30 like toyota recommends. They built the truck, and they know best

 

Welcome to TW, OP!

This ^^ is solid advice.

 

Ya I would stick with what toyota said to run. They designed that engine for that oil.

 

x10

 

Toyota engineers told Toyota to tell dealers to use 5w20 in everything. Dealers didnt take it upon themselves to change the weight, because they dont care what miliage you get.

 

"Recommended" and "best" may be two different beasties when it comes to oil. You can't sell cars in the US and many other countries unless you have a certain CAFE or Corporate Average Fuel Economy rating. If a company is falling below the necessary rating it will often recommend a lower viscosity oil. Some companies have recommended different viscosity grades in the exact same model from one year to the next for just this purpose.

 

I would stick to the 5w30 I'm a tech and I have seen that a lot of manufacturers are switching to thinner oils like 0w20 to improve fuel mileage and reduce cost of ownership but they don't have to worry about anything after 100,000 mi

 

This is interesting and news to me. Can you provide a link of some sort that states this? Thanks.

 

I have no link. But I worked at a Toyota dealer from '05-'08 and we were told to change all our bulk oil by Toyota and were given a chart that stated the few years/models that still required 5w30. It wasn't the decision of the dealership, if anything it was more hassle for us because we now had to deal with 2 different weights rather than simply 5w30


Dealers are also not going to take that sort of liability risk by themselves. Toyota corp would have to make the decision for warranty coverage etc. Common sense says Toyota isnt going to allow an oil weight change if it were to cause engine issues so that is something engineers would have to research.

 

Do you use 5w20 in your personal truck? I'm curious if there's any significant mpg increase. I have close to 240k miles and have always used 5w30 or 10w30. I wonder what's the real reasoning behind the switch. It can't be solely on increase gas mileage as the OP was told.

 

Like I mentioned above, oil viscosity recommendations are often determined by CAFE ratings. If a manufacturer's average fuel economy for vehicles sold in the US falls below the US government standard, then the manufacturer is fined $5.50 per 0.1 mpg under the standard for every vehicle it produces for the US market. Even though a switch to a thinner oil grade might increase mileage by less than a mile per gallon, if a manufacturer "recommends" the thinner oil this is often enough to meet US fuel economy standards and prevent having to pay millions of dollars in fines.

Edit:

From 1983 to 2003 the US government collected over 650 million dollars in CAFE fines.

 

understood, but doesn't this only apply to new cars/trucks? what does toyota have to gain to recommend a 10yr old truck to change oil viscosity?

 

Personally, I think that the best thing to do, no matter what oil is "recommended" is to find someone who has 300 k plus miles on an original engine that isn't using more than a half a quart of oil between changes and follow what he did.

 

Since 2009 when the truck had only 110k miles on it I have been using 5w-30 Mobil one synthetic high mileage every 8-10k miles.

I drive it hard and I like to stick to Manufacture spec they give for what ever I drive.

Once you start to tinker with things that weren't meant to be.. problems can occur.

on another note, I use Toyota dealer Fuel Filters and spark plugs as well.

Truck now is sitting at a smooth 162k miles and still going strong.

 

5w30 goes in the truck because it's usually cheaper.