Engine oil Mobil or AMSOIL

Have noticed on several times that when I went from Subaru OEM oil to Amsoil BACK to OEM that it runs much quieter and smoother on Amsoil.

But I run Amsoil signature blend in my vehicles. And I also push 15,000-25,000 miles per change.

I have seen my friends and family use amsoil for 25000kms each change and their cars do 200k- 300k without any engine issues.

I already added to engine oil and transmission. 5mpg improvement avg. already.

I use the Mobil 1 Racing 4T 10W-40 which is synthetic *and* meets JASO, just because it is always available at the nearby Walmart.

Switch to Amsoil products and go every 6,000. I honestly would go every 7500 with it if it was me driving that much.

I use M1 5-30 because I've ran it in well over a dozen cars and beat on all of them without issue, and it's only $28 for a gallon jug at walmart. I also run liqui moly ceratec to silence the typewriter tick it developed around 35k.

Send your used oil to Blackstone or Amsoil for analysis and all of your questions about oil will be answered.

MOBIL 1 every 5k miles. Not the worst or the best oill

Amsoil's biggest 'benefit' is a longer service life. Their additive pack doesn't break down as quickly, so you can run it longer between oil changes. However, if you're paying twice as much and running it twice as long, it's a wash and you're not gaining anything. When I was selling Amsoil, I had a modified 4 banger and a high mileage 24v that had both been running Rotella for the entire time that I owned them before switching to T6 when it was introduced. I pulled UOA samples every 1k miles, then switched to Amsoil Signature after 5k and did the same thing except I pushed the Cummins to 10k. Zero improvement in fuel dilution, wear markers, or carbon build-up. After seeing there was no real-world benefit, I stopped selling it. I won't market a product I don't believe in, let alone one that I see as an outright scam.