IIRC a different weight oil can mess with the MDS system and cause it to not work properly.
4.7L engine = no MDS
Originally Posted by hdsport
'08 JGC, 4.7 V-8, 77,000 mi.
I know that the Owner's book calls out a 5W-20 oil viscosity.
I would like to put in 10W-30 for my winter stay in Florida.
Anyone see a problem in using 10W-30????
Also, will be doing a 2500 mi trip from Fla to Pa and back.
I lean towards the slightly higher viscosity for the Fla heat and interstate driving.
Your advice is appreciated.
Not sure if the requirements changed in 08 ,and wkjeeps does not list it, but my 05 owners manual and service manual state 5W30 for the 3.7/4.7L engines . But as stated above you would be fine with 5w20 . all the HEMI guys in florida and other hot climates are running it .
Not sure if the requirements changed in 08 ,and wkjeeps does not list it, but my 05 owners manual and service manual state 5W30 for the 3.7/4.7L engines .
Our last WK was an '06 and it took 30 weight. They switched from 30 to 20 between '06 and '07.
Long story short - If you can squeeze more miles per gallon out of the current set-up by merely changing oil weights, then it saves the auto makers a butt load of money. The 20 weight oil yielded slightly better fuel econ (and I mean slightly) when the engineers ran the engines through their rigamarole of tests. It's a case where the results are greater than the sum of its parts. From an individual perspective the difference is less than miniscule. From a manufacturer's perspective getting the best fuel econ for your entire fleet of built vehicles goes a long way with the gub'ment.
Any of those oil weights will work fine. I use 5w20 because thats what the cap says??
Funny that is the only change they did to the engine,just changed the oil fill cap.The 4.7 was designed for 5w-30 and can use 10w30 in hotter climates with no issues.I have run into issues at work from the 3.8/3.7/4.7's running 5w-20 and 0w-20 oil,mainly high oil consumption but when switched to 5w-30 or 10w-30 the problem goes away.
'02 Liberty sitting on 35" tires,HP44,RockJock60,and AtlasII t-case