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dubwarren 09-12-2010 01:11 PM

5w 20 vs 10w 30
I think i get better mpg using 5w20, but could i use 10w 30 or 10w 40 in my 11 overland with the 5.7? The manual calls for 5w 20, but doesnt that oil lead to quicker breakdown of the engine? I'd rather use the best oil i can get my hands on but dont want to mess the rig up....i know you guys will have the answer..I want a long engine life, any suggestions?

Scottina06 09-12-2010 01:14 PM

Re: 5w 20 vs 10w 30
maybe try the mobil1 exteneded performance 5w-20? I have used that in everything from my wifes lexus to my jeep to a 600 hp 3000GT Vr4

MeanDean 09-12-2010 01:29 PM

Re: 5w 20 vs 10w 30
I read somewhere (owner's manual?) that the 5W-20 is required for the MDS to function properly. It doesn't make any sense at all to me why this is, but I would at least stick to the 5W-20 until the warranty has expired.

dubwarren 09-12-2010 02:01 PM

Re: 5w 20 vs 10w 30

robpp 09-12-2010 02:03 PM

Re: 5w 20 vs 10w 30
in the wk, there is a cel that is thrown if the system detects the wrong weight oil, i would suspect the wk2 has the same.

when the hemi first came out, they recommended 5-30. then the MDS flutter became common so they changed it to 5-20. then they noticied a slight i9ncrease in gas mileage so they expanded the 5-20 to the 4.7 and 3.7.

Joe in PA 09-12-2010 02:08 PM

Re: 5w 20 vs 10w 30
Why would you believe that using 5w20 would lead to a quicker engine breakdown than 10w30 or 10w40? if anything, attempting to second guess the 5w20 called for in the owners manual for the 5.7L hemi will cause more problems than it will help solve.

dubwarren 09-12-2010 02:34 PM

Re: 5w 20 vs 10w 30
i read somewhere that the thinner the oil is the quicker an engine will break down, i thought 5w 20 was thinner and only called for to get better gas mileage. all assumptions....i have no solid info or knowledge to back that up, enlighten me.

Joe in PA 09-12-2010 03:09 PM

Re: 5w 20 vs 10w 30
If you run a "thinner" oil in an engine than it was designed to use, there is certainly a chance that the engine will wear out prematurely. Same can be said for using a "thicker" oil than an engine is designed to use. But to suggest that a "thinner" oil will cause premature engine wear regardless of the engine in question, simply is not true. Stick to what the owners manual calls for in your new vehicle and do not pay attention to what others may tell you. Same goes for the fluid specifications for your new vehicle's transmission, transfer case, axle lube, coolant ...........

dubwarren 09-12-2010 03:18 PM

Re: 5w 20 vs 10w 30
cool. will do.

LTrainGC 09-12-2010 04:46 PM

Re: 5w 20 vs 10w 30
As said before, 5W-20 is required for MDS to function properly.

Marlin 09-13-2010 08:24 PM

Re: 5w 20 vs 10w 30
^^^ Truth, but due to unavailabilty of it here in Oz other than genuine I use Mobil1, 5W/30 in mine with no ill effects.

Kev- 09-14-2010 02:42 PM

Re: 5w 20 vs 10w 30
Newer engines are being built with tighter tolerances. If you put thicker oil in there, it could easily mean having inadequate lubrication of the tight spots where it's needed most.

Do either of the engines call for synthetic? Even if not, I'd suggest running a very high quality synthetic of the correct weight. But if it does, make sure to always use synthetic.

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