Oil Catch Can, Eliminate that knock!

Been reading up a bit. Some years back, for a soap making project (which never got started ) we got a 2-pound container of Potassium Hydroxide (KOH, aka caustic pot ash), a little different than Sodium Hydroxide (NaOH, aka caustic pot ash, or lye), but with similar efficacy.



worth noting: ONLY use this on the stainless steel cooler.

Of the two, the Pottasium Hydroxide is maybe easier to get (popular in soapmaking), and more effective: Asking Google's AI:

Which would be better for cleaning carbon build-up in an automotive, stainless steel Exhaust Gas Recirculation component

The response:

For cleaning carbon build-up in a stainless steel Exhaust Gas Recirculation (EGR) component, Potassium Hydroxide (KOH) is generally the better choice between the two hydroxides.

Why Potassium Hydroxide (KOH) is Preferred

• Superior Penetration: KOH molecules are slightly smaller than NaOH molecules, which allows them to penetrate hard, baked-on carbon and grease more effectively.
• Better Rinsing: KOH is more soluble in water, especially hot water, making it easier to rinse away without leaving the hazy residue often left by sodium hydroxide.
• Lower Corrosivity for Efficiency: While both are corrosive, KOH is often cited as providing better efficiency with less risk of localized corrosion on certain metal surfaces when used correctly.

Critical Precautions for EGR Components
While KOH is effective on stainless steel, you must verify the exact materials in your EGR assembly:

• Avoid Aluminum: Many EGR housings are made of aluminum. Both NaOH and KOH will vigorously corrode aluminum, creating small pits and holes that actually cause carbon to stick faster in the future.
• Protect Electronics: Do not submerge the component if it has integrated electrical motors or vacuum diaphragms, as the caustic solution will destroy them.
• Manual Pre-cleaning: For heavy build-up, use a screwdriver or scraper to remove large chunks of carbon first so the chemical can reach the base layer.

 

Gentlemen, great discussion! I am all for an OCC installation on the Gen 3 Prius’s. However, as I understand it, California does not allow them. And their installation is an automatic fail during a smog test. I live in SoCal and I hate the notion that I would have to temporarily uninstall it every 2 years for testing only to reinstall it! Personally, I always run my cars a 1/2 quart low. So far, my Gen 3 has 150k on the odometer and, knock on wood, no engine dancing has materialized!

 

Catch cans can blow seals if neglected which is why newer factory designs were integrated into the engine and have a drain back to the oil sump.

 

It's not THAT hard to remove and install, every 2 years, is it???
WHY would you run half a quart low? They less oil, the less cooling.

And depending on whether you have the updated pistons and rings, you'll start burning
oil before too long. You should keep an eye on the oil level...

 

?? Half a quart below the full mark (i.e., 1.1 quart above the low mark), or half a quart below the low mark, which would be risky?

 

Set it up so it’s at least easy to pull out, and clean if necessary. An extra (intact) PCV hose is $10 USD at most.