Dakota Durango Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter #1
Hello, I have a 2003 4.7 Durango with 265k on it and read around and see people saying I should run a heavier weight oil and some people say I should use a lighter weight oil I. Currently running 5w30 should I change the type of oil?
 

·
Registered
Joined
·
599 Posts
The basic concept is this:
1. As the engine parts wear out normally over time the clearances between the parts open up.
2. As the oil pump parts wear out over time, it also is subject to the clearance between parts opening up a bit.
These two factors cause the oil pressure to drop over time.

Low oil pressure is bad because it means you are not pushing oil to the parts of the engine that are farthest from the oil pump. This is typically the top end parts. Additionally, when starting the engine the oil pressure might build slowly and that causes more wear at that time.

What you can do is check your oil pressure with a gauge that screws into the oil pressure sensor port.
If the oil pressure is too low, you can use a heavier weight oil. That will improve the oil pressure.

How low is too low?
Realistically speaking you have an old engine so the book values for a new engine do not matter a whole lot.
You want to have SOME oil pressure at idle when the engine is hot. even 5 psi. (5 psi is way better than none.)

By a dumb coincidence, I checked mine the other day while doing something else and i had 14 at idle. (43,000 on the engine)

If you go to a 40 weight oil you will see an improvement. It might not be a lot but it will be some.
 

·
Registered
1988 Dodge Dakota LWB RC 3.9V6 3 speed auto
Joined
·
1,441 Posts
Isn't the factory weight supposed to be 5W20 on a 4.7?

In any case - one thing that complicates the figuring is that a lot of the "Heavier is better!" folks are using pushrod motors; yours is a OHC motor, and needs a thinner oil to pump up into the heads quicker.

You also need to use an oil filter with an appropriate anti-drainback valve.

I'd be using a high quality synthetic of the weight called out for in the owner's manual if I were you.

Oh - wait - that's what I'm doing on my 1988 after the motor rebuild! (For me it's 5W40 year round in Northwest Louisiana; if I lived up north, it'd be 5W30 winter and 5W40 summer. But that's a 3.9 pushrod; OHC I'd probably be 5W20 year round.)

RwP
 

·
Registered
Joined
·
599 Posts
The factory oil is:
5w30 for most people and 10w30 in extreme heat.

The point Ralph is that the engine is not the way it left the factory.
The OIL PUMP needs to be able to move the oil. Wear in the pump makes it less likely to be able to pump a thin oil to the top end. This is true whether it is Overhead Cam or pushrod.

Measure the oil pressure at idle when it is hot.
Make a judgement call.
Go to 40 weight oil and see if you have an improvement.
You need to have some oil pressure at idle.
I'm out.
Good luck to the OP. I hope you get some more miles out of your vehicle.
 

·
Registered
Joined
·
149 Posts
With 302K mi, I run 0W20 and my engine thrives on it. I have tested 0W20 with a mechanical pressure gauge and found no discernible difference on the gauge from 5W30.

The vast majority of engine wear occurs when cold...not when hot... and we have coolant, radiators and fans to control the heat.

The manual specified 5W30 for the earlier 4.7, but that changed to 5W20 on later models, although tolerances stayed the same. Standard fill at any Dodge/Chrysler dealership is 5W20 for any 4.7, no matter the year and has been that way for many years.

We must remember, oil has improved in leaps and bounds. If you do the research, you will find that 0W20 often performs better in torture tests, than 5W30 or heavier oils. It's not about viscosity, it's about base oil and additive pack. Furthermore, 0W20 is only zero weight when cold for faster flow, but is the same 20 weight as 5W20 at normal operating temp. I would never run a 40 weight in my engine. Yes, pressure may rise but due to resistance to flow. Cold start is where you really get wear and you need fast flow at that point.

One thing on these high mileage 4.7L is that you'll get the hydraulic lifter clatter until the lifters become pressurized with oil. They quiet down faster with 0-weight so that tells me oil arrives in the top end faster.
 

·
Registered
Joined
·
696 Posts
I have a high mile Dakota
0w-40 Full Synthetic like Mobil 1 high mileage if using some oil otherwise the 20,000 mile stuff is the best
order is
ESP
Annual Protection
the rest of the family
most wear is at start up with a Fi motor
cam't see where you are and that does make a difference
The 0W-40 is really just at the top of the 30 weight range
 
1 - 6 of 6 Posts
Top