Mobil 1300 OK in Ford 3.5 V6?

Joined
May 31, 2005
Messages
150
Location
Tucson
I've been using 5W30 since owning a Taurus with the 3.5 V6, even though the manual and oil cap demand I use 5W20. This is a non-turbo, non-DI engine, it's very quiet and has been trouble-free, and is just now coming off the 6 year powertrain warranty. What I currently have in my "stash" is 2 gal. of Mobil Delvac 1300 Super 15W40, thinking of using this for the next oil change for the Taurus. Any reason not to use it? I'm in AZ, it's going to get up around 100F or more every day for the next couple months. Also, I have a bad habit of adding some Lubegard Biotech at every oil change.
 
I don't see why you couldn't use up your stash of 15W40 in that engine especially in that AZ heat. But I am curious as to what others will add.

Also, I have nothing against LubeGard BioTech(I like ILI products) however, I just dont think it's needed. But, if you already have some in your stash, use it up as well.
 
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I used 15w40 and SAE 40 in both a 98 Taurus and 95 Windstar van. But then again, I'm both a thickie and Mr monograde.
 
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Ran it in my last GMC 5.3L (non AFM) … what I have left is for the 19 HP Briggs …
 
High ambient temperature does not dictate using a thicker oil. Low ambient temperature does dictate using a lower Winter rated oil (0w-x or 5w-x)
 
Originally Posted by neo3
I've been using 5W30 since owning a Taurus with the 3.5 V6, even though the manual and oil cap demand I use 5W20.


Where is the word 'demand" written in either the Owners Manual or oil fill-cap? Does it say 'require"? Or does it say 'recommend"?

Your warranty time is over. Try the heavier oil and let us know how it works out. You could probably continue with it, during the Tuscon winters.
Wait..... does Tuscon even have a winter? I've never been Southwest. Wait again..... never Northwest either.
 
Originally Posted by ka9mnx
My Ranger manual doesn't say "demands" but says "only use 5w-20".

That's close-enough to a demand - if it concludes by saying.... 'in any climate" or stops the sentence right there & then.
...... thanks for the quick check & see.
 
Originally Posted by neo3
I've been using 5W30 since owning a Taurus with the 3.5 V6, even though the manual and oil cap demand I use 5W20. This is a non-turbo, non-DI engine, it's very quiet and has been trouble-free, and is just now coming off the 6 year powertrain warranty. What I currently have in my "stash" is 2 gal. of Mobil Delvac 1300 Super 15W40, thinking of using this for the next oil change for the Taurus. Any reason not to use it? I'm in AZ, it's going to get up around 100F or more every day for the next couple months. Also, I have a bad habit of adding some Lubegard Biotech at every oil change.


I doubt it will hurt it. If 15W-40 would hurt it on a 70F cold start Ford wouldn't recommend using 5W-20 down to -22F.

Ford has been known to recommend heavy oil to quiet noisy cam phasers and chains so I think any speculation about heavier oil and potential cam phaser issues is a lot of worry over nothing.

I've never seen any evidence the 3.5L Ti-VCT needs anything other than the 5W-20 but if 5W-30 helps you sleep better no biggie.
 
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Originally Posted by ka9mnx
High ambient temperature does not dictate using a thicker oil. Low ambient temperature does dictate using a lower Winter rated oil (0w-x or 5w-x)


In many cases, that is absolutely incorrect. There are times where ultra low viscosity oils and low HTHS oils are incapable of maintaining adequate film strength under high temperatures. Additionally, many vehicles do not have oil temperature management systems. This is particularly true with older designs.

Clearly, many modern engines are designed around a low viscosity oil. Even so, some engines require more viscosity in Saudi Arabia, for example. It's common for hot areas of the middle east to use synthetic 5W-30/40 where the very same vehicles the USA would use 0W-20.
 
Originally Posted by Cujet
In many cases, that is absolutely incorrect. There are times where ultra low viscosity oils and low HTHS oils are incapable of maintaining adequate film strength under high temperatures. Additionally, many vehicles do not have oil temperature management systems. This is particularly true with older designs.

If your cooling system is working the engine will not know, or care, what the ambient temperature is. I would agree with you if your coolant system couldn't keep up.
 
Originally Posted by neo3
What I currently have in my "stash" is 2 gal. of Mobil Delvac 1300 Super 15W40, thinking of using this for the next oil change for the Taurus. Any reason not to use it?


I'm in a similar situation.
You could do what I do and mix the 15W-40 with 0W-20.
My Kia Optima loves this blend!
 
Originally Posted by ka9mnx
If your cooling system is working the engine will not know, or care, what the ambient temperature is. I would agree with you if your coolant system couldn't keep up.


Oil temperature and coolant temperature are not directly proportional. Track day enthusiasts regularly see this [as do Middle East motorists] . The 278 degree oil temperature in the quote below shows just how out of control oil temperatures can get even with an OEM oil cooler. I understand the temptation to think that oil temperatures will be managed by the oil flowing over relatively cooler components. The reality is that oil temperatures can spiral out of control in high ambient temperatures, engine destruction can and does result.

It's good to remember that oil transfers heat much more slowly than water. Oil temperatures can and do continue to rise under some circumstances.

Quote: "To be fair, it was pretty hot at the track, about 28 C (84F) on the hottest session, and I was pushing the car pretty hard. Sessions are 20 mins, and I was near the end of it. I checked the performance pages display and my engine oil temp had got up to 137 C, or about 278 Fahrenheit At that point, I backed off and did a cooldown lap. The car had no warning lights or limp modes or anything like that, still had plenty of power, but that scared me a little. The coolant temp stayed pretty normal, I don't think it exceeded 105 C"
 
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Originally Posted by Rand
Thats the reason the track mustang gets 5w50 instead of 5w30?


Exactly! It also points to a failure to manage oil temperatures well. The 5.0L engine obviously can produce 460HP without damage on 5W-20 oil. That is, until oil temperatures are excessive.

Well configured track day cars can use the very thin oils we have today. To do so, they must manage oil temperatures actively and use components engineered for the thin oil. One secret is the use of very light pistons, rods, pins, ring packs and so on. This reduces inertial loads significantly, allowing a less robust oil to protect.

A rule of thumb for oil temperature is to design for 220 deg F, giving a wide margin of safety to 260F.

Another rule of thumb, 0W-20 and 5W-20 oils are unable to provide adequate protection for conventional engines, at 300F.
 
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Well if you go through with it, then give an update back on how the performance was. I also have a 2018 Ford Taurus I use 5w30 the first time I changed it and it runs fine then I went to 0w20. It does seem to actually have better fuel mileage with 0w20. Other than that it runs the same to me
 
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