Who has made the switch from 5W 30 to 5W20 in their 97 up trucks??? Will it hurt to change weights on a 97 with 75,000 miles on it? Also how many miles between oil changes??
Lariat#1

 

After that long, I'd keep doing what you've been doing. Your motor is good and broken in and this late in the game, I'd be hard pressed to believe you'd even see any fuel mileage increase at all...which BTW would be the only reason to change anyways.

As for how often to change...what have you been doing all this time??

 

It should make no difference at all. The 5w-20w may give you a little better fuel economy but I'm betting you won't even notice it. As far as engine protection 5w-20, 5w-30, 10w-30 will all work just fine. Just buy a brand name SAE rated oil and change it every 4000 miles or so. A Motorcraft oil filter is also highly recommended and changed at every oil change.

 

yeah would it be ok for me to switch from 10w30 down to 5w30? at 106,000 miles? sorry for asking in your thread, lariat1

 

I run 5w-30w year round. Even 10w-30 sometimes. Switch back and forth whenever. I even ran 5w-50w in mine for over a year. Truck never knew the difference. We performed dyno testing on these engines using everything from 5w-20 to 5w-50w. In fact the 5w-50w was standard factory fill on the GT-40 and Condor modulars. The key is using good oil and filter and changing the oil at regular intervals. During extreme cold weather using the 5w-20 is preferred as it gets circulated faster but the 5w-30 is probably only milliseconds behind it.

 

thanks. yeah thats why i wanted to switch mainly because the winter, and i could just run 5w30 all year

 

From what I've read, Ford recommends 5w20 for my 02, so thats what I run.

 

I was at my local dealership 4 years ago getting an oil change, and there was a Ford Engineer flown onsite there to inspect a Mustang Cobra engine failure. I was picking his mind about a few things, including oil viscosity, and he told me this...

The tolerances between modulars that originally required 5W-30 and engines that were speced with 5W-20 are exactly the same, but after 5W-20 became widely available Ford switched to it.

Partly for improved fuel economy, but they also found thru testing that the engine lubricated better and improved long term reliability as well. That is why Ford back-speced it to older engines because it would benefit them.

So it makes sense to me. If it's strictly for CAFE reasons, they would not have back-speced older modulars to 5W-20. Why would Ford risk going to thinner oil on older engines if they didn't have to?

 

Let me give you guys a short lesson on lubrication....especially the bottom end of the engine where everything is dependent on it being good and tight. At the main bearings and rod bearings, as the engine breaks in, the bearing will wear at a microscopic elliptical shape. This allows for a wedge of oil to form just in front of the load direction on the bearing. This is per design as attempting to have a perfect circle doesn't lend itself to good lubrication as the oil would have no place to be. It would just be squeezed out or it would take extreme amounts of pressure to keep an oil film in place. The thinner oils, like a 5w-20, are great when the engine is new. They run far cooler and do a far better job. With today's oil bases, the film strengths are enormous by comparison of the oils of your fathers. So we don't have to run the heavy viscositys like dad did when pulling a trailer or under heavy load conditions. We can still use the Xw-20 oils and do it better. BUT, and here's the meat folks, when the engine develops wear, and they all do, at the bearings, the lighter weight oils tend to run out quicker between the bearings and the crank. What this means is that the rings may be in a starvation situation as the oil is running out of the bearings instead of being sprayed in adequate amounts on the cylinder walls and bottoms of pistons. The best example of this is the Ford Vulcan 3.0. Rarely do the 3.0's go much past 100,000 miles without needing the rear main replaced. When the rear main gets worn, it beats the seal out and hence, the leak. But the rest of the bottom end is also in need of replacement as it is worn too. It's one of those things where the light should go on at the brain cells. If the bearings are worn, expect ring wear to increase dramatically as they are starving for oil. As an engine wears over time, you need to move out of the xw-20 into the Xw-30 Energy Conserving oils and if expecting long life, you probably need to move into the High Mileage oils at a later time. The heavier oils having a greater resistance to flow will bring the volume of oil back up at the rings as the heavier oil isn't going to run out of the bearings as fast. I have 87,000 miles on my 4.6. I'll be switching over to the 5w-30 EC oils at the next change. If I still have this truck at 130-140,000 miles, I will be switching over to the High Mileage oils. If you have been using the heavier oils already, stay with them. As the bearings break in, they break in to the viscosity of the oil you are using. If you ran a 15w-40 oil since new, there will be a larger wear gap between the crank and the bearing from the viscosity of the oil. Going to a lighter oil will surely cause excessive wear at the rings and engine failure at an early age. Hope that explains in plain english some of the issues with viscosity.

 

My '97 Explorer is suppose to use 5W30. At the dealership, they use 5W20. I've never had a problem with the 5W20 from the dealership.

 

I have been using 10-30 dino for all of my life until recently. I am now using Mobil 1 with a motorcraft filter.
The old '81 truck never ran better.

 

I switched my '97 4.6L over from 5w-30 ??? to 5w-20 Motorcraft semi-synth shortly after I bought it. 5w-20 is easier for me to find in the large jugs...just a bit cheaper when buying oil compared to buying single quart bottles. We've got four 4.6/5.4 modulars (two are 97s and two are newer) around the farm to keep fed so it makes inventory easier too.
At 146k, I haven't noticed any difference and it's not using any oil or showing any lower pressure on the gauge compared to 5w-30.

I'm still a little old-fashioned...don't believe in long oil change intervals even when running full synth. I stick with 3000 miles for a max oil change interval on pretty much everything. We've gone up to 5000 on the folks' 4.6L Lincoln a couple times but the oil really starts to "color" when it gets past 3000 so we usually change it out then.

 

And so does everyone who gets oil changes from Jiffy Lube.