My manual says I should use anywhere from 5w30, 10w30, to 15w40 depending on the temperature outside. I live in Alabama so I see anwhere from 15 degrees fahrenheit to 100 degrees fahrenheit. I am thinking 10w30 would be a good compromise. I want to run the thinnest oil I can for gas mileage without losing engine protection. I will be towing a lot but I will drive it only occasionally so maybe 5-10k miles a year.
Deciding on which weight diesel oil for 2000 7.3L Ford Diesel
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I want to use a Pennzoil Ultra Platinum because in my other cars this oil keeps those engines incredibly clean but I dont see the diesel spec listed for these oils. I don't know of a similarly effective oil that works so well at cleaning the engine that is made for a diesel engine.
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well since you live in the south like me, some good 15w40 synthetic will do very good in the engine, something like rotella T6. The difference between 30 and 40 weight is very small, so the mpg increase you will see will not make any real difference.
15w40. The pz platinum you mentioned is not a diesel oil.
15w40 diesel oil. Oil weight isn't going to make a bit of difference in your gas mileage on that rig. Delvac is cheap and widely liked.
I'd go with a 15W40, especially if it's the HEUI 7.3L in your sig.
Been looking online. Rotella T5 Ultra 10w30 seems comparable to the Ultra Platinum cleaning performance that I am looking for in an oil.
I see you all are saying 15w40 but I hate thick viscosity oils. My dad ran castrol gtx conventional 20w50 in a 1991 toyota 4x4 pickup with a v6 engine. I thought he was insane. Still, he used it for over 200,000 miles till we sold it. I like the thought on the diesel engine running smoother and easier with the 10w30.
Motorcraft Super Duty 15w40
id use a 15w-40 they're usually around 14cst kv100 while 10w-40's are around 15-16 so there not as thick as people think. Tractor supply and rural king usually have buckets of the stuff for cheap and if you're driving that infrequently and towing you're gonna see basically no mpg gain whatsoever. Home depot tends to sell gtx diesel for 10.97 and i've bought some before. Supertech diesel is also great stuff.
dnewton3
Staff member
Did you just come into ownership of the PSD? Seems odd you'd be asking about oil grade unless you've not owned one before.
The 7.3L PSD uses it's oil for the HEUI injection system. So you don't want something that's too thick or too thin. The HEUI will shear oil down, but it seems to slow/stop the effects when a thinner oil is used. If you use a 40 grade, it will shear to a 30 grade at some point. If you use a 30 grade, it will shear less if any at all. I cannot explain why this is so, but I've seen (literally) hundreds of UOAs to know this is just a symptom of the system's operations. So ...
Either the 10w-30 or 15w-40 will do a good job in your area. As much as I'm a fan of extended OCIs, in this case I'd say just stick to 5k mile intervals using conventional oil. The 7.3L is reknowned for it's longevity. The grade choices are going to make a minimal difference in fuel economy; not enough you'd see in your 5k mile annual use. The 7.3L PSDs run just fine on conventional oil. Don't get hung up on brands; even house brands will do fine. Just make sure to get a qualified HDEO; CJ-4 or CK-4 will do fine.
Also, when you do an OCI, make sure to vacuum the oil out of the HPOP and then refill it along with the sump capacity. The HPOP does not drain down quickly and won't get a good oil exchange in a quick OCI.
The 7.3L PSD uses it's oil for the HEUI injection system. So you don't want something that's too thick or too thin. The HEUI will shear oil down, but it seems to slow/stop the effects when a thinner oil is used. If you use a 40 grade, it will shear to a 30 grade at some point. If you use a 30 grade, it will shear less if any at all. I cannot explain why this is so, but I've seen (literally) hundreds of UOAs to know this is just a symptom of the system's operations. So ...
Either the 10w-30 or 15w-40 will do a good job in your area. As much as I'm a fan of extended OCIs, in this case I'd say just stick to 5k mile intervals using conventional oil. The 7.3L is reknowned for it's longevity. The grade choices are going to make a minimal difference in fuel economy; not enough you'd see in your 5k mile annual use. The 7.3L PSDs run just fine on conventional oil. Don't get hung up on brands; even house brands will do fine. Just make sure to get a qualified HDEO; CJ-4 or CK-4 will do fine.
Also, when you do an OCI, make sure to vacuum the oil out of the HPOP and then refill it along with the sump capacity. The HPOP does not drain down quickly and won't get a good oil exchange in a quick OCI.
Yes. I just bought it. It is my first diesel. I'm learning all of the terms like "hpop" an "heui" for the first time.
I see the Ultra Platinum oil cleaning my engines so well that they run much better; i.e. smoother, less noisy, etc.. That is why I'm looking for an oil with a potent additive package. I have no idea what this engine sounded like or ran like when it was new so I want to clean up the inside of the engine as much as I can. With 287,000 miles on it, I should be able to get another 200,000 miles out of it with what I hear about the longevity of these engines.
Thanks for the heads up. I will look into this procedure of vacuuming.
You are going to choke when you see your new oil is dark black 15 seconds after changing it.
Up front, you need to know that medium duty diesels like the 7.3 are nothing like passenger car gas engines so you should not base anything off your previous experience.
You need to use a diesel rated oil and 15w40 is what probably >90% of people use in the 7.3 PowerStroke but 10w30 diesel oil is fine, too. Change it religiously at no more than 5K miles to keep the fuel injection system happy. You're going to be buying 4 gallons per oil change so boutique oil is not usually what people choose to use, and frankly, the truck will in all likelihood be a rolling junk heap long before the engine wears out running standard Delo, Delvac or Rotella, assuming it got good maintenance over it's life.
Happy trucking!
You need to use a diesel rated oil and 15w40 is what probably >90% of people use in the 7.3 PowerStroke but 10w30 diesel oil is fine, too. Change it religiously at no more than 5K miles to keep the fuel injection system happy. You're going to be buying 4 gallons per oil change so boutique oil is not usually what people choose to use, and frankly, the truck will in all likelihood be a rolling junk heap long before the engine wears out running standard Delo, Delvac or Rotella, assuming it got good maintenance over it's life.
Happy trucking!
In the 7.3 and 6.0 PSD trucks I have owned, I’ve always used 5W40. Usually Mobil Delvac 1 ESP. $23/gallon at Rural king.
What makes you hate thick oil?
Welcome to the 7.3 club. As with anyone that ends up with one of these the best advice I can give is to learn about Brian at BTS in Lead Hill AR. Brian is ridiculously good with everything about these trucks.
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