Rotella 15w40 T4, T5, or T6???

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Oct 21, 2021
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I have been doing some research on the various Rotella 15w40 oils and have a few question hopefully you all can help with. I have been using the T4 claimed "synthetic blend" for some time and considering the benefits of switching to T5 or T6. Was wondering if anyone has made this change and seen any benefits in switching to the synthetic blend or full synthetic products? The only issues I have being an OTR driver is there seems to be a huge price difference in getting the T5 and T6 oil changes compared to T4. It seems to average about $175-$225 more for the higher grade synthetics compared to T4. Also there have been times I've been in need of an oil change and out in some remote area that doesn't have the T5 or T6 at all. Sometimes time and location restraints do factor in when needing an oil change on the road and T4 seems to be the most readily available between the three products. I have actually been mixing a synthetic additive called FR3 from Hot Shot Secrets with the T4 for the past few oil changes. The FR3 costs an extra $50 per oil change requiring 64oz in a semi truck. My current approach has been to create my own improved synthetic blend of the T4 and stick to the the T4 since the cost is significantly lower and oil is consistently available. Wondering if it would be efficient to continue my method or switching to T5 or T6 and cutting out the FR3 additive? Also any thoughts on the risks of switching between all three oils based on shop availability? I have heard risks of switching back to a conventional after using synthetic but have never done this and can't say I know much about the specific subject. Any thoughts and feedback on anything discussed here would be greatly appreciated!

Here are links to the FR3 product if you would like to check it out:
 
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I've read about a decent amount of syn diesel oil guys ended up switching back to a regular diesel since there wasn't a big improvement to merit the near 2x price jump and i agree i just got 6 gals of supertech diesel.

And no the fr3 isn't necessary but that's not to say its bad. It does work but for the most part with steady loads over long periods it's not a big concern. Also it's not a tbn booster so it doesn't really make the oil last longer.

I'd only get a 5w-40 diesel oil if i lived in a very cold place or was super concerned about a more fragile engine.

But for the most part the manufacturers don't expect you to run a full syn diesel oil but would like for the oil to have the certifications they ask for which many of them have.

The vast majority of engines wont have ill effects from going to a lower grade.

What's your oil change interval and average miles per engine running hour?
 

muzictrucking

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Hi Javier thanks for taking the time to respond here. You have provided some good insight from your experience. I stick to changing the oil about every 15-16k miles and average about 45 miles per engine run hour. Any additional thoughts on this?
 
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The Volvo VDS 4.5 test is a test where the oil is ran for 360 hours and passes without too much oxidation and it's a pretty stout test and doing the quick maths it looks like you're around the 330 to 340 hour mark and that's fine.

That's perfectly acceptable for a big rig. It looks like you do a bit more idling time but those intervals are all right. I would probably just do one oil analysis including TBN at 16,000 Miles because some 4.5 rated oils can do more.
 

AutoMechanic

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My dad uses that exact oil in his truck. He prefers T4 because of the price and it’s what he has used for years. He used the synthetic blend once didn’t notice any difference it still used a gallon like it normally does. He has also mixed them together and not noticed anything different either. 15,000 mile oil changes with both oils when used. Now the only hard thing is finding it in stores it’s nowhere around here.
 

muzictrucking

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The Volvo VDS 4.5 test is a test where the oil is ran for 360 hours and passes without too much oxidation and it's a pretty stout test and doing the quick maths it looks like you're around the 330 to 340 hour mark and that's fine.

That's perfectly acceptable for a big rig. It looks like you do a bit more idling time but those intervals are all right. I would probably just do one oil analysis including TBN at 16,000 Miles because some 4.5 rated oils can do more.
Thanks! I actually do oil analysis at each change and all levels have been normal.
 

muzictrucking

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My dad uses that exact oil in his truck. He prefers T4 because of the price and it’s what he has used for years. He used the synthetic blend once didn’t notice any difference it still used a gallon like it normally does. He has also mixed them together and not noticed anything different either. 15,000 mile oil changes with both oils when used. Now the only hard thing is finding it in stores it’s nowhere around here.
Thanks for the feedback, I think I’ll stick with the T4 it seems to be doing the job well and is affordable and available everywhere.
 
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Ditch the additive, it may not do anything helpful at all, and will void your oil warranty, if you ever wanted to make a claim. I sold probably a quarter million gallons of T4 from the time Shell bought out Pennzoil-Quaker State until I retired twelve years later. A solid product, a good value, and at under 20K OCI you're just fine.
 

muzictrucking

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Ditch the additive, it may not do anything helpful at all, and will void your oil warranty, if you ever wanted to make a claim. I sold probably a quarter million gallons of T4 from the time Shell bought out Pennzoil-Quaker State until I retired twelve years later. A solid product, a good value, and at under 20K OCI you're just fine.
Thanks for the feedback 👍
 

muzictrucking

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what has the tbh been like
Actually I’ve only done a few samples so far and all contaminants ppm have been low. I was reviewing the reports again today and realized the TBN is not on it and called the lab company and found out they didn’t include it in the sample package. I just added the TBN test so will be getting those numbers soon. Just sent a used oil sample in today along with a fresh sample to baseline the used oil reports off. Thanks for taking the time to discuss this here it helped me look again and resolve that with the lab company!
 
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What's up with the T6 shortage? Guys online are saying they can't find any. I went to my Walmart and the shelves were indeed bare. Apparently there's a national shortage of T6. Anybody have info on when this may be resolved?
 

muzictrucking

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No idea but I saw some at a Pilot in Indiana the other day. That’s one reason I started this thread to get some outside feedback because the T4 seems to be the most widely available of the three.
 
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unless things changed it was noted that only a small amount of synthetic usually cheeper group III need be blended in to advertise as a semi synthetic. blending some full synthetic of the same brand could be an option. snooping in Wallys today i noted not much of any diesel oil on the shelves! discovered an old thread while searching diesel oil about hot shots branded products for good prices on PAO's as well
 
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Went to Auto zone today, Berlin Tpke Newington Ct. bought to jugs T5 $22.00 Ea. Still hag 3 jugs left.

Was there 2 weeks ago and bought the last jug, so either they are short stocking, or they can actually get the t5, didn't see any T4 , orT6

Convert
 
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not sure if this will help you or not , i picked up a 2.5 gal jug of t6 earlier this year at runnings ,with a sale , with rebates it was like 29$ and you could apply for multiple rebates , the link below was the rebate i used , its still open , and can apply for 4 rebates

 
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