Genuine GM Fluid 88862628 Rust Penetrant and Inhibitor - 11 oz.

Works better than literally anything else for breaking stuck fasteners free. Give it a quick spray, wait ten minutes or so, and tap with a hammer or other suitable tool. Beats every other penetrant hands-down.WEAR EYE PROTECTION!!! This stuff is no joke, get it in your eyes and anyone around you will think you're having a seizure.

Former GM dealer tech. I’ve been using this stuff for nearly three decades. It was formerly called Heat Valve Penetrant, for unsticking and lubricating exhaust to carburetor heat valves. WD40 is not a good lubricant and is not a penetrant at all. PB Blaster is decent and I have used it, but if you want the best stuff, use the GM stuff. It comes out sort of foamy and really clings to rusted surfaces. Admittedly it does not smell very good, and I’m sure it’s not good to breathe too much, so adequate PPE and ventilation are appropriate, but this is the stuff to get if you are working with rusted fasteners. And, because it foams and clings, a little goes a long way. I still regularly work on vehicles and a can will last me a year or more.

This stuff is great. Broke free my tire carrier on my Wrangler that was rusted and would not move. I will never use anything else.

Works as designed, value for the money.

Been using this as a dealership technician for over 20 years. Great for stuck tie rods and exhaust bolts.

The product is great I have used it for years, but when I received it there was no plastic applicator

If you are trying to save a part or hard to find/expensive fitting, spray onto whatever you"re trying to get apart several times over several days. Dont rush it. Used this 35 years ago at the dealership. Was called heat valve lube back when carbs were on cars. Do not get in ur eyes...

I use this stuff daily. Helps loosen rusty bleeder screws and anything else I need to get loose.