Engine oil weight

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Got a 2002 Ford F-150 the other day. 4.2L 5sp-manual tranny. I read off the oil fill cap "5W-20". I've always used 10W-30 oil in all my engines. Why should I use 5W-20?

posted by  DodgeRida67

Are you sure it's not 5W30? 5W20????? And if it does state 5W20, I would use it because it says so.

posted by  lectroid

I did a little research on the matter and found that the reason ford recommends 5W-20(yes, it's 5W-20, only ford and honda recommend it) is because the C.A.F.E told them to. Only for better gas milage. I'm going to get the specs on the bearing clearances before I make up my mind, but after finding that out I'm leaning towards 10W-30. Especially since it's getting to be around 95 degrees here soon on average. Thanks though.

posted by  DodgeRida67

Most folks I know with later model Ford 4.6L V8's use 5W30 instead of 5W20 in this area and south of here

I have an earlier version of the 4.6L (a 1992) with similar clearances to the later ones and use 10W30 in it year round. I use Havoline Synthetic although it is a group III stock instead of group IV like Mobil 1

posted by  tbaxleyjr

I have a 99 4.0 v6, which calls for 5W30, would it be safe to use 10W30?

posted by  lectroid

Ford?

posted by  tbaxleyjr

Sorry, yes Ford :oops:

posted by  lectroid

If the car calls for 5W30, it will probably allow 10W30 as an optional warm weather oil

From a common sense standpoint, 10w30 is probably OK I hesitate to say it is or it isn't since I don't know the 4.0L V-6 as well as I know the 4.6L V-8 and don't want to put a person in a situation where a dealer will deny a warranty claim (if any is availabe from Ford) over lube oil viscosity

The owners book calls for 5W30 in my 1992 Crown Vic 4.6 L with 10W30 as the optional oil for winter temperatures >0F. I opted for the 10W30 since we don't get really cold weather in Chattanooga and my car is parked inside the garage overnight most nights. I ran 5W30 in my Crown Vic for one oil change cycle and heard what I think was valve chatter which went away when I started using 10W30.

The newer Vics call for 5W20 but the engine design has not changed significantly concerning ring gap clearances, camshaft and crankshaft bearing clearances and I know of some folks using 5W30 in theirs.

During summer time, it probably would not matter much but I would look @ my low temp conditions and make sure I was Ok then.

posted by  tbaxleyjr

Can I ASSUME from this post, it would be OK to use 10W30 in the summer time, say 80degree and above? There is no option in the owners manual for a different oil viscosity?

posted by  lectroid

If the car was mine, I would probably use 10W30 in the summer since the 30 in 5W30 and 10W30 represents the weight of the oil @ 100F.

posted by  tbaxleyjr

Thanks, I didn't know that. The 5 and 10, I presume is the weight of the oil at 0 degree?

posted by  lectroid

yep the 5 or 10 number is the 0F SAE oil weight. I looked @ one of my lubrication books and the summer test temperature is 100C (212F) - I need to llearn to type

A look @ the SAE and ASTM charts for lubricant specifications shows @ 0F, a 5W 30 oil has no minimum viscosity and a maximum of 13 cSts while a 10W30 will have a minimum of 13 cSts and a maximum of 26 cSts.

@ 212F (100C) the viscosity for 30 wt oil ranges from 9.3 cSts to 12.6 cSts

What this says is a 5W30 meets the above SAE and API requirements for 5W wt oil @ 0F and 30 wt @ 212F and 10W30 meets SAE and API requirements for 10W wt oil @ 0F and 30 wt @ 212F

Thats the reason I am not too concerned about summer performance of the oil but made the statement about winter cold start temperatures.

Most lubricant manufacturers will have data sheets available (you have to dig deep sometimes to get past the sales slickys used to attract consumers). The link to Chevron-Texaco (if it works - if not search their site for cbest) gives examples of data sheets available for the lubricants.

https://www.cbest.chevron.com/msdsServer/controller?module=com.chevron.lube s.msds.bus.BusPDSList

posted by  tbaxleyjr

:confused:You're all way too smart. I'm sitting here reading all this techie jargon and my face contorted to this: :tard:

posted by  93GrandAm

If you hang around here long enough you'll eventually know exactly what were talking about and have your own opinions. :thumbs:

posted by  DodgeRida67

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