I saw this a while back and thought it would be good to share on this forum as well. If anyone enjoys working on their own cars this information is invaluable. I typically stick to using the Liquid Wrench penetrating oil as it's available at all auto parts stores and isn't too terribly expensive. Works very well and allows you to be able to use almost half the torque of PB Blaster which I see recommended a lot.


"For all of you that are mechanically inclined..... Penetrating Oils Compared A study done by Machinist's Workshop magazine in their April 2007 issue looked at different penetrating oils to see which one did the best job of removing a rusted bolt by measuring the pounds of torque required to loosen the bolt once treated. If the study was scientifically accurate, it turns out a home brew works best! Here's the summary of the test results:

Penetrating oil .......... Average load

None ..................... 516 pounds

WD-40 .................... 238 pounds

PB Blaster ............... 214 pounds

Liquid Wrench ............ 127 pounds

Kano Kroil ............... 106 pounds

ATF-Acetone mix.............53 pounds

The Automatic Transmission fluid (ATF)-Acetone mix was a "home brew" mix of 50 - 50 automatic transmission fluid and acetone. Note the "home brew" was better than any commercial product in this one particular test. A local machinist group mixed up a batch and all now use it with equally good results. Note also that "Liquid Wrench" is about as good as "Kroil" for about 20% of the price."

Link can be found here:

Penetrating oil comparisons - The Garage Journal Board

 

Good job. I've been a big Kroil user for a while. It's good, but expensive. I've heard for years that the ATF (or PSF)/acetone mix was good but never saw any empirical evidence. I'll mix some up and try it next time.

 

I believe this is the same study referenced throughout the video above..he does a simple test at the end.

Thanks OP for the reminder about needing to make some in the near future. I happen to be running low on Kroil and I saw this awhile back about acetone & atf. Kroil was my standard go to and I always brought it up when I would see friends using PB Blaster or Liquid Wrench.

 

im definitely going to give this atf/acetone mixture a try. i know those damn spark plugs on the ford triton motors with the 9/16 plug are a real pain in the ***. hopefully this atf/acetone penetrant can also break loose engine carbon.

 

My father has an F250 with a triton setup (it's a 2000 I believe) as his beater, hauling brush truck. I can tell you this mix does work for exactly for those stubborn plugs! He had soaked in PBB for an evening and had zero luck. He called me up, I referenced the ChrisFix video, he had some cheap syn ATF around and he mixed up w/ some acetone from Ace in equal parts. 30 min soak, he said almost an immediately release after applying some torque to them. Mind you, he's in his upper 60's, but still spry as they come.