I recently purchased a 2003 expy with a 5.4. I live in North Mississippi, hot and humid. The book says 5w20. I also have a '98 f150 with a 5.4. I run 10w30 in it.

Should I stick with the 5w20? Why would it matter?

Thanks guys.

Bradm

 

u can only use 5w20 on the new engines dont use a thicker oil doesnt flow as good most people think its better for their engines but their wrong it doesnt flow as well through the heads and cause premature bearing and lifter wear.

 

Along that line, the 4.6L and 5.4L engines are OHC (overhead cam) engines and they require a good oil flow to reduce wear, especially at start up. Also these engines are built to much tighter tolerances than earlier engines, so a thinner oil gets to these tighter spaces more easily. Most 5W-20 oils are a synthetic blend, and this blend is what these engines like. Now, this is only my opinion, and you can be sure you'll get lots of different opinions on your question. But I've read a lot of posts about oil on this forum, and most replies from those who have had expereince with these engines since they came out in the late 90's point to using 5W-20. I have had Motorcraft 5W-20 in my '03 since new and I have had no problems. My truck now has over 37k, it runs like a top.

 

I would use 5w20 if you can. 5w30 is fine, and there are many people that run 10w30 with no problems.

 

HI!... I only run VALVOLINE 10-W-30 in my 5.4. The 1ST week I had my truck the crap thin oil FORD put in it from the factory was already dirty and starting to break down. Since then I switched to 10-W-30. Been running it for over 6 years and I beat the crap out of my 5.4. Currently has 180,000 kms on it. I change my oil every 3000-3200KMS and ONLY run K&N racing oil filters. When I start my truck up, my oil pressure gauge immediately jumps to 90PSI. No oil pressure issues here. I would suggest run thicker oil. FORD only runs the **** water oil so they can pass their fleet emissions testing.

 

I agree with Neal....5-20 is mainly for EPA emmisions testing and fuel economy.

 

Neal. I expected something from you like: Whats the difference between
5W-20 and a canoe? Nothing, they're both f#()#ing close to water!

To add to the confusion, there are numerous SAE papers written on the subject of 5W-20 and even lighter oils. The main driver for the lighter stuff
is reduced friction and hence better fuel economy. I've seen 1 - 1.5 % type numbers in SAE papers. A heck of a lot of testing is done by OEMs and oil mfgrs (real ones that is) before it is approved for use in an OEM engine.
Extensive durability testing is done in fleets and on dynos by both OEMs and oil mfgrs before the oils are put on the market.
The main driver for 5W-20 is fuel economy, not emissions. There are additive packages that have been formulated that reduce cat poisoning, that stuff
came along about the same time. Many things to consider in an oil formulation for performance, fuel economy, durability, etc etc.

Some functionality like variable cam timing can be affected by oil viscosity.
Running really heavy stuff will affect that.

Basically, if you follow what the owners manual tells you to put in the engine and what frequency to change it at, you'll be fine.

My rule of thumb is, keep the oil clean. If you're doing alot of short trips
and not getting the crankcase nice and toasty to burn off condensation
then you don't have to do the severe duty change interval.

When I used to have my 4.6 4V cobra, I was in Neal's range of 3000 kms / 2000 miles and just stuck with whatever the Ford spec was. Gearheads tend to be finicky about keeping the main source of power running tip top, along with every other freakin thing on the vehicle.
Now with the cobra long gone and family haulers all around me, I also live a heck of a lot farther from work and the crankcase has plenty of time to get nice and warm. I change about every
5000 miles. I know that will get me to 200,000 miles easily.

Bottom line, if you want longevity, stay pretty close to factory spec viscosity and make sure it is API certified and meets the required service level spec'd by Ford. And for pete's sake keep clean oil in the thing. Its cheap insurance.

Contrary to many an opinion on oil type and change interval, synth vs. non etc etc...the OEMs and oil mfg's do study this crap to death.
You can be pretty sure the factory stuff's engineered to work for your application.

Happy oil changin'

 

Incorrect. Ford has updated their oil recommendations. They now recommend the Motorcraft semi-synthetic 5W20 exclusively for most engines dating back to the 70s. There are a few exceptions, but our trucks are not one of them.

Personally, I'll stick with 5W30 in mine.

-Joe