Why does ford use .5w30 in the 4.0 ??

Status
Not open for further replies.
C

crazyoildude

Joined
Jul 23, 2008
Messages
9,808
Location
New Jersey
I was just curious why ford uses 5w30 in the 4.0 and 5w20 in everything else...
I am now using 5w30 in all my 4.6 engines they seem to run a lot quieter and smoother... I will be going to an engine rebuilders meeting for a couple of classes on Monday and there will be a gm rep a ford rep and a nissan rep there lets see what they have to say i will also ask all the other engine guys what weight they use and i will report back on monday nite
 
I saw a document on line a couple of years ago that had Ford letterhead claiming that it was because of the oil pump not handling the thinner oil well.

Didn't make sense to me but the letter looked credible.

I have one of the older OHV 4.0's and run 10W30.
 
There are a lot of recent threads about this. I haven't really seen any concrete evidence, other than Ford TSB's saying the 4.0 needs 5w30.
 
Originally Posted By: Tempest
I saw a document on line a couple of years ago that had Ford letterhead claiming that it was because of the oil pump not handling the thinner oil well.

Didn't make sense to me but the letter looked credible.

I have one of the older OHV 4.0's and run 10W30.


This is my understanding as well. Interesting note: The new SHO also has 5w30 on the cap.
 
Originally Posted By: Tempest
I saw a document on line a couple of years ago that had Ford letterhead claiming that it was because of the oil pump not handling the thinner oil well.



Makes you wonder if 5W30 quickly shears to a 5W20 anyway, why not just use the 5W20?

Guys on the Explorer forums seem to think the thicker 3OW is needed to keep oil pressure high enough as the engine has oil powered chain tensioners that are of weak desingn.

Again only speculation...
 
Last edited:
Curious about this myself now that I'm driving a 4.0 powered Ranger. 5w30 is fine by me, nothing else we own uses 5w20 and it's simpler when the cars and even the yard equipment can all use the same oil.

I'll have to search some of these other threads.
 
Its the oil pump on the older 4.0's. The guys who put real pressure gauges recorded some pretty low readings at idle and even at 2000rpm its lower than most. Guys who are rebuilding them are opting for a higher volume pump and getting good results. I should ask one them if they would like to run some 5w-20 with the new pumps.
 
Quote:
Makes you wonder if 5W30 quickly shears to a 5W20 anyway, why not just use the 5W20?

Exactly what had me confused. BUT, a 20 grade can technically start at 5.6 cSt so I guess they have to cover all of their bases.

A 30 grade will probably only get down to about 9 cSt even after shearing.
 
The oil pump in the 4.0L Ford engine was not designed for a 20 grade oil. There are several threads discussing this. Ford back spec'd engines to 5W20 that could handle it and benefit from it. Engines prior to 1993, and the 4.0L engine for example were not back spec'd IIRC.
 
I thought they were going to 5W-20 in some cars to try to get fuel economy up a tick. I will never use it in anything I own.

As for "5-30 shearing to 5-20 quickly", I would say if it does, you need to change to a better brand of oil. The viscosity increasers should not go away quickly in auto usage. In bikes, the oil runs through the gearbox which chops the VI's up some, but cars shouldn't have that problem.
 
Last edited:
Oil Pump Volume

"Some of our carryover Engine Designs are not yet completed with 5W-20. For instance, the 4.0L engine's oil pump must be redesigned for more oil flow before 5W-20 can be used. As we change engine designs, we will recommend 5W-20. Some engine designs will never be able to accommodate 5W-20."
 
Originally Posted By: Bluestream
Mod, you sound like you know what you are talking about.

I still am going to use the 5W20 in my 4.0 in the winter this year.


I dont understand. Your being told the oil pump dont produce enough flow for ford to be comfortable with 5w20 , yet are still going to use it. More than likely it will be fine, but for the very little gain, why risk it?
 
Last edited:
Originally Posted By: jstutz
Originally Posted By: Bluestream
Mod, you sound like you know what you are talking about.

I still am going to use the 5W20 in my 4.0 in the winter this year.


I dont understand. Your being told the oil pump dont produce enough flow for ford to be comfortable with 5w20 , yet are still going to use it. More than likely it will be fine, but for the very little gain, why risk it?


Using the 5w20 in the 4.0 makes no sense to me whatsoever.
 
In my area, in the winter the 5W20 will be thicker than the 5W30 I use in the summer. SO why not. The important things is the thickness of the oil, the numbers don't really mean anything
 
The oil system is over extended! That engine is a SOHC-retrofit pushrod engine. Now much more oil flow is needed around the chains, guides and in the lifters which are in the head now. To simplify, there are probably double the lube points now in SOHC form then there was in pushrod form. If the oil pump on the original Cologne was barely adequate then, it's running on the jagged edge now with all the SOHC hardware to lube. My buddy has this truck, he gets free oil changes from the dealer. We suspect theyre using bulk 5w20 in everything, including the ranger, because when he lugs the engine the oil light comes on steady! The truck is only 3 or so years old!

Originally Posted By: tuckman
Its the oil pump on the older 4.0's. The guys who put real pressure gauges recorded some pretty low readings at idle and even at 2000rpm its lower than most. Guys who are rebuilding them are opting for a higher volume pump and getting good results. I should ask one them if they would like to run some 5w-20 with the new pumps.


I would redily agree with this based on what I know so far
 
I'd pass on the 5W20. Once the engine reaches operating temps the 20 grade oil is a 20 grade oil. Now if it is in extreme cold and short trips then I don't think the 20 grade oil will do any harm. For me, my engine reaches operating temps even during the dead of winter. That is the reason I won't use 5W20 in my E-150, it wasn't back spec'd to a 20 grade oil either. I stick with a 30 grade in that, even though a 20 grade oil would make life easier for me. JMO
 
Originally Posted By: Bluestream
In my area, in the winter the 5W20 will be thicker than the 5W30 I use in the summer. SO why not. The important things is the thickness of the oil, the numbers don't really mean anything


I have to respectfully disagree. A w20 is at most going to be 9.5cSt when on. Maybe im off a little on that number. If you doing alot of short trips i guess i see no problem but the engine is probably going to get up to temp. If a w30 is borderline adequate, why push your luck. This is not a x is better than y, it is simply that your truck is not designed for 5w20. Like i said, it probably wont hurt it but i just dont understand the risk. If yours happens to be on the high side of the tolerance and you get a little more flow than most, maybe you will get lucky. It will just be an expensive mistake for relatively no gain. Anyway, let us know how it works.
 
Status
Not open for further replies.

Similar threads

U
OCI and oil selection 2024 Ford Transit
2
Replies
31
Views
957
midnightlaundry
Ronin73
2023 Ford F150 3.5 EcoBoost Recommendation
Replies
17
Views
1K
Whimsey
S
What kind of oil do you use in your Ford 3.5 N.A. engine..
2
Replies
28
Views
1K
Scott S
Au{R}oN
Oil Spec that replace Ford WSS-M2C913-D, if exists
Replies
17
Views
2K
ctechbob
S
API versus Euro oil, for the same engine
Replies
17
Views
1K
KCJeep
Back
Top