Time for a new oil in the '08 Dodge 4.7...

[opposite_locker]

OCI will continue to be 8k (~2 months) under severe service conditions (high rpm w/lots of engine braking, dusty conditions, extended idling, etc.).

Have a choice between M1 0w30, M1 5w30 HM, M1 10w30 HM, and M1 0w40 from the "black friday" stash. Will probably try the 0w30 this time around due to the relatively cooler (but not freezing) temps...save the thicker stuff for the summer, when it becomes "ridiculous service" conditions.

Chrysler (or is it CAFE?) calls for a 5w20 in this engine (310hp '08 4.7L SOHC), and though the 20wt oils have worked well thus far, the engine really seems to like a slightly thicker oil. Motor currently has 115k miles and runs like a top with zero oil consumption...has only run the below-listed oils since factory fill.

How I'd rate what I've used so far, in this application:
1. Mobil 1 0w40
2. German Castrol 0w30
3. Pennzoil Ultra 5w20
4. Mobil 1 0w20
5. Pennzoil Platinum 5w20

All of these oils seem to have had no problem lasting 7500+ miles under "severe service", except for PP 5w20, which had to be changed at 6k because the motor became very noisy. Ranking is purely subjective, based on how the motor ran & sounded with these oils...

 

[umungus1122]

As you said, given the choices, try the M1 0w-30 during the cooler season, while saving the thicker stuff for the heat.

 

[440Magnum]

Interesting that I see this thread, as today happens to be a day when I'm driving an 08 Ram with a 310HP 4.7 also. Although this one has only 16,000 miles on it (my elderly father's truck).

I've also pondered the best oil choice for this engine. Since the factory fill, all its seen is M1 5w20 (sometimes regular, sometimes EP).

The engine runs great, and since Xw20 oils have worked so superbly for the very similar Ford Modular family of engines, I'm very leery of trying anything thicker at all. My only consideration so far would be 0w20 for its (assumed, not really known) better base stock.

When people say "the engine really seems to like a slightly thicker oil," I'm curious as to why. Is this based on oil analyses? It was UOAs that convinced me that the Jeep 4.0 works better with Xw40 HDEO than it does with Xw30 PCMO. Before I switched the 4.7 from a proven Xw20, I'd want to see some hard evidence. Claims of "it feels smoother" are not hard evidence, and "its quieter" is at best "firm" evidence, not quite hard evidence ;-) What about oil pressure? Have you put a real gauge on your 4.7 instead of the factory "idiot gauge" which just snaps to mid-range and stays there when the oil pressure is above a threshold? I HATE that gauge and wish the Ram had at least as good a gauge as the Jeeps, which are actually reasonably accurate when checked against a mechanical gauge. If the Xw20 pressure is dropping to zilch in the heat of summer, then that might be a reason to move to an Xw30, or even M1 0w40.

Someone on here once said something to the effect that even though there really is no universal oil, M1 0w40 might be the closest thing at present. I have to agree with that... I doubt it would actively hurt a 4.7, although I'd want to see if the oil pressure peaks too high at maximum RPM and might possibly put the filter into bypass.

 

[opposite_locker]

Quote:
When people say "the engine really seems to like a slightly thicker oil," I'm curious as to why. Is this based on oil analyses? It was UOAs that convinced me that the Jeep 4.0 works better with Xw40 HDEO than it does with Xw30 PCMO. Before I switched the 4.7 from a proven Xw20, I'd want to see some hard evidence. Claims of "it feels smoother" are not hard evidence, and "its quieter" is at best "firm" evidence, not quite hard evidence ;-) What about oil pressure? Have you put a real gauge on your 4.7 instead of the factory "idiot gauge" which just snaps to mid-range and stays there when the oil pressure is above a threshold? I HATE that gauge and wish the Ram had at least as good a gauge as the Jeeps, which are actually reasonably accurate when checked against a mechanical gauge. If the Xw20 pressure is dropping to zilch in the heat of summer, then that might be a reason to move to an Xw30, or even M1 0w40.

Someone on here once said something to the effect that even though there really is no universal oil, M1 0w40 might be the closest thing at present. I have to agree with that... I doubt it would actively hurt a 4.7, although I'd want to see if the oil pressure peaks too high at maximum RPM and might possibly put the filter into bypass.


Because my truck is a 6-speed manual that gets worked VERY hard daily to the tune of 40k+ miles per year, I have a bit better feel for my truck than most do of their vehicles. I can immediately tell if something is wrong or changes with the throttle response, since the truck sees at least 100 heel/toe downshifts daily (no joke), because it felt different from the last few hundred times. If the idle even hiccups or develops the slightest lope, I notice it...not because I'm trying to nor because I have some super-human ability to feel what my car is feeling, but because I spend SO much time driving this thing and it has become so routine, that any change is immediately noticed.

I know this sounds retarded, but I'm sure that those of you that spend much of your time in a vehicle (i.e. truck drivers) will notice any little change in the way your rig is running, whether positive or negative.

That being said, this engine has always run fairly well on a 20wt oil, and there is probably no reason to change under normal driving conditions. But when climbing up Pacheco Pass in 100 degree heat at 4500rpm in 3rd gear with 2k lbs of fruit in the bed, the motor runs & sounds better on a thicker oil.

I believe the 4.7L was originally specced for a 5w30 oil, and still is outside of the USA. Because of this, I see no potential problems arising from upping to a 30wt oil (or thin 40wt that shears to a thick-30, like M1 0w40).

And yes, I agree that M1 0w40 is the closest thing to the perfect univerasl OTC oil available.

 

[crazyoildude]

5w20 flows faster and runs cooler

 

[440Magnum]

Originally Posted By: opposite_locker

I know this sounds retarded, but I'm sure that those of you that spend much of your time in a vehicle (i.e. truck drivers) will notice any little change in the way your rig is running, whether positive or negative.


I understand that- I logged well over 400k miles in one car, and had a really good feel for its every sound and vibration. But I also noticed that relative humidity and other external conditions had WAY more effect on it than what grade or brand of oil I ran. In fact I never noticed *anything* it did differently related to oil grade, other than the behavior of the oil pressure gauge. If I noticed a *consistent* difference in sound/vibration/etc. in the same stretch of road under different weather conditions, then yeah, I concluded that something else was afoot like a wheel bearing failing or a suspension part getting worn. I just never noticed anything really change the sound and feel of the engine.

 

[opposite_locker]

Quote:
But I also noticed that relative humidity and other external conditions had WAY more effect on it than what grade or brand of oil I ran


I absolutely agree.

Got the Mobil 1 0w30 in to replace the 8k-mile-old PU 5w20. First observation: smoother idle, but this is most likely attributable to fresh oil more than anything else.

Also, valvetrain noise has noticeably decreased, which is what I've experienced every time in the past I switched from a 20wt to a thicker oil. For some reason, the top end on my 4.7 has always been louder with a 20wt oil. Even thought it was an unavoidable inherent characteristic of the engine for the first 40k miles on M1 0w20. Switched to PP 5w20 and it became worse. Switched to GC for a few changes and noise basically disappeared, but the thicker oil made the motor a touch more sluggish and thirsty. Then switched back to M1 0w20 and noise returned, along with a bit of power and MPG. Then tried M1 0w40 and the valvetrain was quiet again, but didn't suffer any noticeable loss of power or mpg as it did on GC. After a couple runs of 0w40, tried out PU 5w20 for a couple OCIs. It was definitely the "quietest" of the 20wt oils and didn't get louder over time as M1 0w20 and especially PP 5w20 did, but the valvetrain once again made itself known.

So far quite pleased with the M1 0w30.