Actually, that is incorrect. The MDS requires the 5W20 to function properly.

A DIRECT QUOTE:

If you have an MDS engine (all current 5.7 engines!), only use 5W20 oil. You need the right oil. If the owner’s manual says something else, follow its advice - but don’t be convinced by a mechanic. Insist on the right grade and if they don’t use it...get a refund and go somewhere else. (You can quote TSB 09-015-04 and 09-013-04, “Vehicles with the Multiple Displacement System must use SAE 5W-20 oil. Failure to do so may result in improper operation of the MDS.”) Watch the mechanic pour it in!

Go look up TSB 09-015-04 and see for yourself.

 

I have the same Question , i disabled the MDS on my truck but still using 5w20 fully synthetic , so can we use thicker oil at least in summer when the temp is very high ??

 

You can, but you don't need to. Follow the manual.

 

the manual says 5w20 and the oil filler cap says 5w20

 

I don't know why this is still a question. Just use 5w-20! The manual says use it for a reason

 

So the oil filters that are out there for synthetics that claim 10,000 mile protection are just false avertising?

 

Those are the bypass oil filters and they do some kind of magic idk about to be able to last so long lol

 

Well said.

It is NOT nessecary to change a filter at 3,000 miles even if you are running your oil longer. That is a proven fact. Ask anybody running an oil pressure gauge as well.

Unless you are running in extreme conditions putting immense loads on your truck day in and day out, you could easily go 4-5k between and oil and filter change with absolutley no negative impact at all on your engines lifespan. I proved that fact 30,000 miles ago by doing a lube oil sample right before an oil change at 3,000 miles and then right before an oil change at 5,000 miles. The numbers were different, but even at 5k, were not even close to being an issue.

 

It still baffles me that people think the company who built the engine does not know how to maintain it. If Chrysler thought a heavier grade oil was nessecasry, they would spec it. The fact that they don't proves you do not need to go with heavier oil. No engine company would spec an inferior weight of oil that might lead to failures and bad press. Even if you have the MDS disabled (which seems silly, but that is another story) you should still run 5W-20. It's what the engine was designed to run on.

Can anybody here produce a case where a 5.7 Hemi had premature failure due to running 5W-20 oil that was changed at reasonable intervals and not a heavier grade of oil? If not, stick with what they ask for.

As for filters, their are plenty of excellent resources on which ones to use. But the most detailed filter review i have ever seen where the person cut open and flow tested every brand on the market pointed to only a handful of models worth using. One of them was the Mobil 1 filter which i use because it's the only one on the list that they carry locally. But the Mopar filters are fine as well.

 

I currently run Penzoil High Mileage in my 03 which is a partial synthetic. I have run that oil in everytruck i have ever owned and love it to death. I wont switch to a full synthetic because i have heard and tend to believe that doing so in an older truck which has more wear and tear can cause some minor leaks here and there. Throughout the years as my trucks have gotten older i have increased from 5-20 to 10-20 even 10-30 at one point. I run a heavier oil here in the summer months in Arizona because that heat can really do a number to your engine. The key is changing at regular intervals! I change my high mileage oil, fram xg filter, and clean/oil my air filter every 3000 no matter what. I do the same thing on the wifes Civic that runs full synthetic that says it can 7500 miles. Every 3000 no matter what for me. (but what do i know? i have pushed every truck iv had over 220K with no engine issues what so ever)