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dansanch 04-11-2010 12:45 PM

Newbie! Need Help with oil and gas choices
 
Hi there. Just purchased a 05 gc limited hemi with 61K miles. Just installed an Aem intake. Questions, not knowing the type of oil previous owner used, should it be ok to start using mobil 1 5w-20 or should I continue letting dealership change regular oil? Also, should I start using 87 or 89 octane gas? Feel small hesitation when cruising and hardly pushing had at around 40-55 miles/hr. Same happens if at stop pushing gas all the way in several times in a row, it feels as hesitating big time after first push of gas. There is no hesitation of engine when driving and flooring the gas though!
Just got 60k miles service from dealer including fuel injectors, spark plugs, service.
Any comments will be greatly appreciated.

robpp 04-11-2010 01:46 PM

Re: Newbie! Need Help with oil and gas choices
 
is it a 3.7, 4.7, hemi?

4.7 has a trans tsb about hesitiation. you could check if that tsb was ever applied. once past warranty, dealer charges for them......

gc4x4 04-11-2010 03:10 PM

Re: Newbie! Need Help with oil and gas choices
 
If its a Hemi then its probably the mds kicking in and out that you feel.Sometimes its perceived as an abnormal hesitation but its actually the mds working, usually between 40-80 mph at a constant speed.
Btw If you do find out if the PO has been using synthetic, then you should keep using synthetic, otherwise I would use Castrol 5w20, I can swear by Castrol, Ive had no problems using it in my cars at all. Good luck

dansanch 04-11-2010 03:36 PM

Re: Newbie! Need Help with oil and gas choices
 
It is a hemi. Would it hurt to start using synthetic oil at this point? I have heard that it may cause problems if an engine was using regular oil and then switch to synthetic later on.
Regarding gas octane, 87 or 89?

Joe in PA 04-11-2010 04:02 PM

Re: Newbie! Need Help with oil and gas choices
 
If it is a hemi you should be using a synthetic 5w20 in order for the MDS to function properly. As to the octane, use whatever you can get away with and not experience detonation. Running a higher octane than your engine needs or is tuned to use is a waste of money.

Walt 04-11-2010 06:13 PM

Re: Newbie! Need Help with oil and gas choices
 
Quote:

Originally Posted by dansanch (Post 186981)
Hi there. Just purchased a 05 gc limited hemi with 61K miles. Just installed an Aem intake. Questions, not knowing the type of oil previous owner used, should it be ok to start using mobil 1 5w-20 or should I continue letting dealership change regular oil? Also, should I start using 87 or 89 octane gas? Feel small hesitation when cruising and hardly pushing had at around 40-55 miles/hr. Same happens if at stop pushing gas all the way in several times in a row, it feels as hesitating big time after first push of gas. There is no hesitation of engine when driving and flooring the gas though!
Just got 60k miles service from dealer including fuel injectors, spark plugs, service.
Any comments will be greatly appreciated.

First, welcome aboard.

I changed to synthetic oil at 3/36 warranty expiration. It's been Castrol 5W-20 Syntec. You can get it on sale at AutoZone in special offers. Also, it's sold in 5-qt jugs (as is Mobil-1 5W-20) in WalMart for ~$22.00 per jug. HEMI likes synthetic more than dino oil, and burns less between oil changes.

Sounds like your "hesitation" is more-or-less normal for a HEMI. Try doing it in 5th gear, not Overdrive, to see if there is an obvious difference.

You can use 87 octane gasoline, but 89 is "recommended" by Chrysler. I just buy the 89, unless it is not available. Never used 91, so I can't comment on that.

Just my "Limited" experience (pun intended)................:)

dansanch 04-11-2010 06:42 PM

Re: Newbie! Need Help with oil and gas choices
 
Thank you all for your input. I really appreciate your advise and hope to be a long time jeep lover as all of you are.

Scottina06 04-11-2010 07:36 PM

Re: Newbie! Need Help with oil and gas choices
 
yep...thats the throttle lag on the hemis due to the throttle by wire. I recommend the Mobil 1 5w-20 extended performance and a K&N Gold oil filter. Ive used that combo for years on high hp engines

dmsfun 05-08-2010 11:03 AM

Re: Newbie! Need Help with oil and gas choices
 
Hands down, the best oil for the hemi is Royal Purple. I used Mobil 1 and Castroil full syn, and it runs better, stronger and gets better mpg with RP. WIth gas, use 89 Octane and make sure it is not B grade; i.e., get gas from top tier stations like Shell, Mobil, Exxon, Chevron, etc... and avoid Marathon, Sinclair, Walmart, and all cheap discount staions, as they buy low grade gas from small refineries that do not use advanced formulations, and will cause problems down the road. I have visited all the refinery labs in the US, as a supplier of instruments for product testing, and have seen firsthand what the products consists of.

moose158 05-08-2010 11:26 AM

Re: Newbie! Need Help with oil and gas choices
 
I agree with dmsfun on the royal purple. Scottina06 is right on with mobil 1. You cannot go wrong with either oil. I used RP in a high horse Trans am and loved it. I actually just yesterday put RP in my 4.7 wk for the first time, and it def runs smoother and quieter. I had been using mobil 1, but choose to go back to RP because I need all of the life I can get outta this wk, and I know the RP kept the TA together because I certianally wasn't easy on it.. Synthetic is the way to go!

08pretaco 05-08-2010 03:55 PM

Re: Newbie! Need Help with oil and gas choices
 
Oils aren't the same as they were some years ago even if the PO used synthetic you can switch back to regular, the differences now adays are miniscul use whatever oils you have good experiences with. On the gas side: don't bother using an actane your engines not tuned for because your not gonna get a difference in performance, use what's specified in the owners manual or gas door. If you ever do go to a tunable chip for the engine or just over the top and a ecu retune (idk if that's possible) then get the tune for a higher octane if you want and with the tune and 91 you'll be seeing and feeling the difference

1 GRAND 05-08-2010 03:57 PM

Re: Newbie! Need Help with oil and gas choices
 
My Hemi was using a quart of RP between oil changes. Every 3000 miles. I switched to Mobil 1 and have not had to add any oil between changes since the switch.

And your hesitation is like Scott said... Throttle by Wire. Gotta love it. Try to rev it up in park... It will just go to 3000rpms.


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