• Sign Up! To view all forums and unlock additional cool features

    Welcome to the #1 Fiesta ST Forum and Fiesta ST community dedicated to Fiesta ST owners and enthusiasts. Register for an account, it's free and it's easy, so don't hesitate to join the Fiesta ST Forum today!


Isn't 5W-20 Wt. oil a little too light for a Turbocharged Engine?

Messages
231
Likes
135
Location
Corsicana
#41
At that point you basically threw your power train warranty out the window (well, you might be able to 'fake out' some dealers/warranty reps with a very factory looking hybrid, at least until they open it up), so at that point you could use anything you want.

I would go to a 'stout' 0/5W-30 for daily use, and a 'boutique' (Red Line, Motul 300V, Millers, etc.) 0/5W-40 for open track/HPDE use.
I agree that if you upgrade the turbo, the warranty is gone. Mine's just out of warranty, so I'm going to a hybrid. I've always run full synthetic Pennzoil Platinum 5w20 up to this point, but with the added heat and stress, plus the fact that I live in hot Texas, I was thinking that I needed a thicker oil like a 5w30 or 5w40. I don't really plan on tracking my car tho.
 


TyphoonFiST

9000 Post Club
Premium Account
Messages
11,498
Likes
7,987
Location
Rich-fizzield
#42
What about when you're doing a hybrid/big turbo upgrade? Should you step up to something like a 5w40 for daily driving because of the added heat/stresses? Just curious.

The thicker the oil....the less it is able to dissipate the heat so the answer is NO. There is a big misconception about that the thicker it is that it will be cooler but that is incorrect.
 


M-Sport fan

9000 Post Club
Messages
14,000
Likes
6,700
Location
Princeton, N.J.
#43
The thicker the oil....the less it is able to dissipate the heat so the answer is NO. There is a big misconception about that the thicker it is that it will be cooler but that is incorrect.
CORRECT, as long as it is of the base stock quality which will totally resist the viscosity breakdown effect of said heat.
I'm guessing that you are pushing the bitog credo of "as thick as necessary, as thin as possible"?

In any case, for southern Tejas, (or any hot southern climate), even the thick (3.8 HTHSV) for it's API number Red Line 5W-30 should NOT add too much pumping viscosity friction to the mix as to be adding to the oil's heat (as long as there are NOT any VVT/cam phaser problems with a 30 weight oil??). [wink]

Run a big/efficient enough oil cooler, and one could use a good quality, very shear stable 0W-20, even in blast furnace ambients, and not have any problems. [:)]
 


TyphoonFiST

9000 Post Club
Premium Account
Messages
11,498
Likes
7,987
Location
Rich-fizzield
#44
Let's just put it this way....most people will not need a thicker oil due to no autocrossing.....no drag racing etc. With tighter tolerances of today's engines a thicker oil can create more heat due to it not being able to be thin enough to creep into all tight crevices of a modern engine. With Ford engineers and the R&D put into this project i'd say either the 0w20...5w20...0w30....5w30 would be alright if you don't mind not meeting Ford's spec etc. I've ran 0w20 and 5w20 and saw no increase or decrease in economy or temps on long road trips or just driving around town. If you wanna make the vehicle temps move down get a bigger intercooler.....Imo. that will increase efficiency more than oil.
 


neeqness

1000 Post Club
Messages
1,398
Likes
166
Location
LA
#45
Let's just put it this way....most people will not need a thicker oil due to no autocrossing.....no drag racing etc. With tighter tolerances of today's engines a thicker oil can create more heat due to it not being able to be thin enough to creep into all tight crevices of a modern engine. With Ford engineers and the R&D put into this project i'd say either the 0w20...5w20...0w30....5w30 would be alright if you don't mind not meeting Ford's spec etc. I've ran 0w20 and 5w20 and saw no increase or decrease in economy or temps on long road trips or just driving around town. If you wanna make the vehicle temps move down get a bigger intercooler.....Imo. that will increase efficiency more than oil.
Well, people don't just use thicker oil to lower temps. You are missing the likely possibility that an oil can be too thin. Unfortunately, some people don't recognize this until it's too late. Not only are their closer tolerances but there is also higher stress. If you thin the oil too much, over time you can cause more wear which ultimately leads to the premature breakdown of parts.

This, is why I would thicken the oil. We are not talking a significant thickness here. 5w30 or 5w40 is not significant. MAYBE if it were 20w50 I would agree with you, but at 5w30 or 10w30, a simple significant rise in ambient temperatures from seasonal changes could justify this alone.
 


TyphoonFiST

9000 Post Club
Premium Account
Messages
11,498
Likes
7,987
Location
Rich-fizzield
#46
I could argue till I'm blue in the face here but chose not to get into fluid thermal dynamics and different types of metal. The moral of this thicker oil story falls back to powertrain warranty....if it doesn't meet Ford spec for weight and use... I wouldn't use it. As you will always have the what if in the back of your mind when shit does hit the fan or if it doesnt.Then you're paying out of pocket just because you chose to use a thicker oil that don't meet Ford spec. Out of powertrain shoot for the moon .....but until then if the women don't find you handsome at least they will find you handy.[rockon]
 


neeqness

1000 Post Club
Messages
1,398
Likes
166
Location
LA
#47
I could argue till I'm blue in the face here but chose not to get into fluid thermal dynamics and different types of metal. The moral of this thicker oil story falls back to powertrain warranty....if it doesn't meet Ford spec for weight and use... I wouldn't use it. As you will always have the what if in the back of your mind when shit does hit the fan or if it doesnt.Then you're paying out of pocket just because you chose to use a thicker oil that don't meet Ford spec. Out of powertrain shoot for the moon .....but until then if the women don't find you handsome at least they will find you handy.[rockon]
I think those people who stuck with spec and now have issues with their power train might disagree. However, I'm not just saying change your fluid for no justifiable reason. If the engine and power train are running smoothly with spec fluids, by all means continue doing so.

However, if you detect signs that your fluids are not lubricating properly and blindly choose to stick to stock fluids, regardless, thats your choice of course. But remember the power train warranty only goes for so long. Extra wear on the engine may or may not cause a problem during that warranty. The way I drive my car, my extended warranty will likely be up sooner based on the mileage alone. I would prefer my vehicle to last much longer than the warranty and I choose not to rely solely on the warranty alone to solve any future issues. Besides, ultimately you have no guarantee the dealer will not blame you for the problem even if you DO use only recommended fluids.
 


M-Sport fan

9000 Post Club
Messages
14,000
Likes
6,700
Location
Princeton, N.J.
#49
The other point about viscosity is that it is futile to go by the SAE/API 'weight' (xW-XX), since some heavy 5W-20s are actually 'thicker' than some 'thinner'/lighter 5W-30s, when one goes by their High Temperature High Shear Viscosity numbers instead of the 'weight' on the bottle.

The API gives A LOT of range and leeway in the actual HTHSV numbers which the manufacturers/blenders are allowed to label their oils with a given xW-XX number. [wink]
 


Last edited:

ROCKYFiestta

Active member
Messages
504
Likes
115
Location
Colorado Springs
#50
w in oil does not stand for weight it stands for winter fyi one of the first things learned in autoshop school
“W” stands for “winter.” When oil grades are hyphenated (i.e. 10W-30), this indicates range of viscosity attainable with this particular oil, namely it behaves less viscous when it is cold or “winter” and thanks to viscosity modifiers
 


ROCKYFiestta

Active member
Messages
504
Likes
115
Location
Colorado Springs
#51
on that note I use the castrol gold bottle also rated for 15k but still change it every 3 months been using a k&n oil filter unless you guys think the ford one is better??

i put the cheaper magnatec castrol on my regular sedan fiesta but same 5w20, it just got really dark after one month of use i was surprised since i barely drove it 200 miles max in that month.
 




Top