HDEO that runs quieter?

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Jul 10, 2025
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Have you used a particular HDEO where you clearly noticed a difference in how loud your engine sounded after switching to it?

I am particularly interested in oils you noticed a definite reduction in volume or of a particular noise/sound.

In my truck with a 7.3, it definitely runs much quieter and smoother after an oil change. Anyone with a 7.3 will confirm that is not a placebo affect with this engine.

It also has much less noise on start-up with an oil having a winter rating of 5 as opposed to 15 regardless of the weather.

It's been awhile, but I feel the Valvoline Premium Blue 5-40 was noticably quieter at first but didn't last as long.
 
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Not necessarily in how you describe but I noticed a big improvement in the cold winter going from 15w to a 5w HDEO on my old 7.3L. On my 6.0L I don't notice near as much difference but it has a lot more compression (7.3L had a lot of miles on it). New oil seems to sound better than used oil but that's not scientific & probably a placebo effect. :LOL:
 
Not necessarily in how you describe but I noticed a big improvement in the cold winter going from 15w to a 5w HDEO on my old 7.3L. On my 6.0L I don't notice near as much difference but it has a lot more compression (7.3L had a lot of miles on it). New oil seems to sound better than used oil but that's not scientific & probably a placebo effect. :LOL:
Well you will see I added to my original post as somehow I accidentally hit post before I was done.

New oil in a 7.3 is definitely not a placebo effect in my book!

My 30 year old girl definitely lets you know it is time for an oil change by how loud it starts to get and doesn't run quite as smoothly. It's crazy how it feels it almost happens overnight!
 
Engines always sound quieter after an oil change. For one thing the oil is cold and thick and this helps to dampen the sound. If the engine was running prior to the change and you're comparing it to that, then this is the reason. Second the new oil is not diluted with fuel or otherwise thinned.

Noise on startup due to the winter rating would be highly dependent on the temperature. Any oil with a 5W rating isn't guaranteed to be thicker or thinner than the same grade with a 15W rating, except at below the testing temperature for the rating. You say "regardless of the weather", if that's the case then it isn't due to the winter rating.
 
Here are a few previous (sometimes lengthy) discussions on this popular topic. A few are essentially identical to your question:

 
Well you will see I added to my original post as somehow I accidentally hit post before I was done.

New oil in a 7.3 is definitely not a placebo effect in my book!

My 30 year old girl definitely lets you know it is time for an oil change by how loud it starts to get and doesn't run quite as smoothly. It's crazy how it feels it almost happens overnight!
Stick with the 5w if you want it to run it's best during winter. That's really the only biggest difference here. If you're trying to quiet it with oil outside of the above conditions...good luck! 7.3L are loud engines. If you're concerned get a stethoscope & put your calibrated ear & listen to the different brands you decide to run. Just ribbing a little. :LOL:
 
I have never noticed a difference in sound with any oil over the last 20+ years with mine. They only way to quiet it is to cut the key off.
 
I thought I was high as a giraffe when this happened last LOF on my diesel. I switched from Rotella T6 5W40 to Mobil 1 ESP 5w40 (it was cold and on sale at Walmart) and I swore the engine sounded quieter.
 
Changed my 1KZTE from Super Tech 15w40 conventional summer oil to Delo XSP 5w40 this weekend and it was noticeably quieter and smoother.

I don't generally subscribe to the idea of "my engine loves XYZ oil" when what most people mean is "my engine didn't immediately blow up on XYZ oil." Any perceived improvement is likely from changing old/used/sheared out of viscosity oil to fresh in-spec oil and doesn't mean anything about whatever oil flavor they chose.

That said, I've run O'Reily's house brand 15w40, Rotella 5w40, and Super Tech 15w40, and now XSP 5w40, and to my completely uncalibrated ear and having listened to only the Super Tech 15w40 and XSP anywhere close to each other, the XSP is the only one I thought changed how the engine sounds.
 
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It's kinda like when your brand new tires ride smoother than the old ones. Of course they do. There's an additional 3/8" of rubber between you and the road. It may or may not also be because it's a better tire, but it's not a fair comparison.

The reason why you changed from your old oil to the new oil is because the old oil was old. If it never got old, there'd be no reason to change to the new. The new is better at being oil because it's new, and not old.
 
I used to own a 2002 F350 4x4 with the 4R100 Auto Transmission with the legendary 7.3, great motor. Who knows, if the truck's body would not have rusted badly, I still may have it. It ran great and was great to drive. I actually took really good care of he truck over the years I owned it.

I usually ran the Motor Craft 15w40, or once in a while Delo 15w40 always with the Motor Craft Oil Filter changing the oil and oil filter every 5000 miles or a little sooner and grease the front end while waiting for the oil and oil filter to drain. Super Easy oil changes with this truck.

Looking back, I wished I would have run a 5w40 diesel oil during the cold months which would have made the 7.3 a little happier even after plugging in.

I now have a 2011 Ram 3500 4x4 and always run the Rotella T6 5w40 year round.
 
My Kubota L2501 has a loud diesel engine. I typically run a synthetic 5w-40 because I use it in the winter to plow. Last year I tried a Kubota branded 15w-40 conventional oil and it was remarkably quieter.
 
My prior truck was 2002 F350 4x4 with the 7.3 made by International. What a great motor and very easy to work on. When I had my 7.3, I always usually ran the Motor Craft 15w40 year round in all climates. I did run Delo 15w40 a few times and always the Motor Craft FL-1995 oil filter always changing the oil and filter every 5000 miles per the manual. I didn't notice any engine noise quieter or louder with either oil, the 7.3 had a distinctive sound which I thought sounded great. If I still had my 7.3 today, I would run Shell Rotella T6 5w40 in it. My 2011 Ram 3500 6.7 Cummins does very well with the Rotella T6 5w40 year round.
 
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