Penetrating oil

Tiny
RIEBE123
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  • 2000 HONDA ACCORD
  • 3.0L
  • V6
  • 2WD
  • AUTOMATIC
  • 136,000 MILES
You guys have been very helpful in the past so maybe you can help me out now. I have to replace my catalytic converter due to a PO420 code. Which I am told almost specifically indicates the catalytic converter is gone and must be replaced. The bolts and nuts are rusted on pretty good. My question is, what is the best penetrating oil you found works the best?
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Monday, February 4th, 2019 AT 4:15 PM

6 Replies

Tiny
CARADIODOC
  • MECHANIC
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I've heard good things about PB Blaster but I never used it myself.

My preference is for Chrysler's Rust Penetrant. I suspect other dealers' parts departments have the same thing under their own name. This stuff goes on black, and sizzles, but if you're going to reuse the parts, it must be removed when you're done, otherwise it opens the way up for moisture to follow it in, then the parts will be even harder to loosen next time.

I can tell you from experience that WD-40 did not work for a project even after soaking for three days. Hit those bolts again with Rust Penetrant and the bolts came loose in less than twenty minutes. This product was originally made to loosen rusted heat riser valves on cars from the 1960's and 1970's.
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Monday, February 4th, 2019 AT 5:53 PM
Tiny
RIEBE123
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Thanks.
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Wednesday, February 6th, 2019 AT 3:28 PM
Tiny
DANNY L
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Hello, I'm Danny.

I was actually a paid participant in a focus group by WD-40 when they introduced the Rust Penetrant line. It's not the regular WD-40 in the blue/yellow can but it's actually made to compete with PB Blaster. I strongly feel it works wonders. You might want to try it. Hope this helps and thanks again for using 2CarPros.
Danny-
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Wednesday, February 6th, 2019 AT 9:40 PM
Tiny
CARADIODOC
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Hi Danny L. Are you referring to the Rust Penetrant from the Chrysler dealers? Or are you saying Chrysler buys it from WD-40 and puts their name on it? They also have a product called MP-50 which in my estimation is the same as WD-40. They refer to that as a "moisture displacer" but it's actually a very light oil.
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Thursday, February 7th, 2019 AT 7:21 PM
Tiny
DANNY L
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Here's what I'm talking about:
I was a paid participant in its introduction. Stuff works wonders.
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Friday, February 8th, 2019 AT 6:19 PM
Tiny
CARADIODOC
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Dandy. My guess is that is something different. Chrysler's stuff was made for freeing up rusted heat riser valves in the 1960's and 1970's.

Many years ago I was doing an antenna job for my boss. The home owner had an old cast iron tripod on the roof and the bolts were rusted tight and starting to twist. I sprayed the snot out of them with WD-40 on a Friday afternoon. Came back the following Monday and the bolts were still twisting. Sprayed them with Rust Penetrant, then went inside to do other parts of the job. Twenty minutes later I was back up on the roof, and all six bolts came loose.

The problem I found later with Rust Penetrant is I started using it on inner and outer tie rod connections during alignments, thinking it would keep the parts from rusting together. We had a lot of customers who came in once a year for maintenance alignments, and on every one of them after I did that, the tie rods were rusted so tight, I needed a torch to get them loose. After that I started using their "Spray White Lube" which is a lithium-based grease. It has a juice that flows into tight places and takes the grease with it. The juice evaporates and leaves the grease behind. Works really well for door hinge pins too. When cars came back a year later, the tie rod ends came loose just like they do on rust-free cars down south. Moral of the story is if you're going to use Rust Penetrant on parts you're going to reuse, be sure to wash the stuff off, then use some other type of grease if necessary. Moisture follows Rust Penetrant in and makes the parts rust even tighter.
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Friday, February 8th, 2019 AT 7:09 PM

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