Best penetrating oil??

[81 SC Ray]

From the weekend warrior garage,

I have to change out a broken heater valve (you know, two of em - left and right) - the bolts are really rusted and I am afraid to break a stud. What is the best penetrating oil - I have never tried to loosen anything so rusted. Fortunately, this is the only rust on the car.

Thanks for the help.

Ray

[rs6er]

PB Blaster for me, but others feel free to chime in.

[Superman]

Maltby's. Can be hard to find, but diesel parts stores usually have it.

[pete3799]

PB blaster, but you will still have to heat the nuts to get them off.
Don't even try them without heat.

[1990C4S]

ATF with varsol in it should work fine. Or ATF and diesel fuel. Or ATF, diesel and brake fluid. Mix up what you got on hand.

The heat is more important than the oil.

[Jim Garfield]

This was recently posted by Curt Egerer on the S site:

"From a friend:

Machinist's Workshop magazine actually tested penetrants for break out torque on rusted nuts. They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment.

Penetrating Oil Type ..... Average Load to Free
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 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. Our local machinist group mixed up a batch and we all now use it with equally good results. Note also that "LiquidWrench" is about as good as "Kroil" for about 20% of the price."

[MBAtarga]

I've also had recommended to me a 50/50 mix of acetone and ATF. I haven't had the opportunity to mix some up and try it out though.

Edit: Jim posted the above as I was typing my response. Scientific evidence that ATF-Acetone works.

[walt]

I have used Kroil for years as do many of the local machine shops - works great. I would like to try the 50/50 mix next but will need to exercise caution around painted finishes.

Walt

[Formerly Steve Wilkinson]

Awhile ago when I stopped in Portland to visit Steve Weiner, he gave me as a parting gift a new can of Zep Super Penetrant. So unless it was something he was desperate to get rid of, I take that as a knowledgeable recommendation.

[IROC]

Originally Posted by walt

I have used Kroil for years as do many of the local machine shops - works great. I would like to try the 50/50 mix next but will need to exercise caution around painted finishes.

Walt

+1. I had a can of Sili-Kroil that was the best stuff I've ever seen.

[88-diamondblue]

+1 on the Kroil. I have used other but none have worked as well

[RWebb]

PB Blaster works well but stinks - I like Kroil.

Loctite now makes a Freeze-Off product which I plan to try next time I need it.

Wurth makes a product too.

The comparison above is hard to interpret as no sample sizes or even test methods are given.

I would never use acetone in a garage. It is toxic and dangerous (ignition hazard).

THe most important factors in any penetrating oil (WD-40 is not a penetrating oil) are time and tapping the joint - so ap it hundreds of times over a week or two after spraying.

[Winter]

If you use Liquid Wrench, let 'er soak. And then hit it again with the LW and let 'er soak, and again. . .

This has worked very well for me, and I'm talking doing the process over a couple of days. And Liquid Wrench is easy to find, relatively cheap.

The suggestions from others here sound good. I've heard good things about Kroil, but haven't run out of LW yet. When I do, I'll try that.

---

Tom '75 targa

[Wintermute]

Wintergreen Oil. Seriously.

Wear gloves.

[GaryR]

Aero-Kroil, really works!

[1990C4S]

Originally Posted by Jim Garfield

The 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.

And note how cheap it is to make. Spray lube is way overpriced.

[Zef]

Mouse milk is the one to beat...
Welcome to Mousemilk

[equality72521]

One more for Kroil. i bought a whole case of it.

[81 SC Ray]

OK - you guys rock - thanks, but, I want to expand my question. I have always done my own work on my cars, but, my cars have never been 28 years old before. So, I have never had to use penetrating oil - from your responses, I am gleaning that I am to:

1. Apply it many times over as long a period as I can.
2. Tap the bolt - the nut - both??
3. How do I "let it soak" when it is a bolt/nut assembly that is perpendicular to the earth on a vertical piece of metal.

NOTE - Thanks for the scientific evidence. I will be going to Autozone and mixing up a batch of acetone and ATF - I will be careful with it (damaging paint - death - all bad).

Thanks.

Ray

[dshepp806]

Kroil....