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Cleaning Intake and EGR - what chemicals would do the best job?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Lares_Mat, Aug 13, 2022.

  1. Lares_Mat

    Lares_Mat Member

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    I'm preparing to do the job and am researching needed tools and chemicals.

    Maybe, I'm trying to reinvent the wheel - if so - let me know ;)

    Here I want to discuss, what chemicals clean the carbon and epoxified deposits in the intake manifold and in the EGR system the best, the easiest, the safest and the quickest (maybe not all at once).

    I know, there are a multitude of descriptions, films and discussions about that, but they are not always consistent. For different people, different agents do the job and they demand a different amount of effort and time...

    I think, it would be worth it to have the best functioning chemicals collected and discussed in one place.

    And the thing is - we should discuss chemicals - not products.
    Of course, a distinct product has a distinct ingredients - if someone can confirm, a product is doing a great job, we should look at the ingredients and try to understand, which one is doing the most and which is only for the good smell there ;)

    The prerequisites for me would be:
    1. the chemicals should be accessible for an average man and that not only in the US (on-line, normal chemical or construction shop, maybe automotive parts shop)
    2. the chemicals should not be excessively harmful to the environment or to the user (working outside or in very well ventilated area, using gloves and eye protection is OK)
    3. the chemicals should do no harm to the cleaned part (I realize, there will be different chemicals for the intake and for the ERG cooler - that's OK)
    4. the chemicals should do the work - minimal scrubbing and no days long soaking at best
    5. the chemicals should not be excessively expensive.

    Disclaimer: I'm not a mechanic, I'm not a chemist!

    Apparently one can not dissolve carbon and we actually do not have to dissolve it.
    We have to dissolve the backed stuff, that holds the carbon sticking to our parts - a kind of resin or epoxy, the carbon is embedded in...

    I did some research and it seems, few chemicals come over and over again in the discussions and descriptions of cleaning carbon deposits, and this are:

    - NaOH (Sodium Hydroxide, attacks aluminium - do the intake manifold have aluminium parts?) eventually with additives. Could be used for intake manifold if you avoid contact with aluminium parts. Here some interesting reading:
    What breaks down burnt carbon deposits? | Physics Forums
    https://www.apriliaforum.com/forums/showthread.php?323620-Cleaning-Spark-Plugs-(for-Colour-Tuning)
    Both links seem to come from one author.

    - CH2Cl2 (Dichloromethane or DCM or methylene chloride or methylene bichloride) - a strong diluter found in products like Aircraft Paint Remover. Here is safety data sheet of Aircraft Paint Remover (I think more products are named similar?): http://kleanstripauto.com/resources/product-resources/3404_18_KS_Aircraft_paint_Remover_SDS_05012019.pdf

    - acetone - this one, I know, removes easily carbon baked on a copper sheet (DIY methode of making printed circuit boards)

    There are many others for sure.

    An additional good stuff to read is here:
    https://www.nylacast.com/wp-content/uploads/2019/04/NylacastChemicalResistanceTable19.pdf

    Our intake manifold is made of PA6 reinforced with fibreglass (PA6-GF30).

    I'm interested in a good discussion about how to quick and simple clean our intake manifold and EGR system and cause as little damage / harm as possible to anything / anyone.
    Of course it can happen, there is no such method at all, but maybe it is - let's see, if we can get closer to it :)

    Best regards

    Mat
     

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  2. PriusCamper

    PriusCamper Senior Member

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    There's a lot of sketchy chemicals in your list. And it's not just which one cleans the best, but which one is most dangerous to your personal health and how much hassle is PPE gonna be. @Mendel Leisk says an overnight soak in Oxyclean with a high pressure wash after is all you need.
     
  3. Lares_Mat

    Lares_Mat Member

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    I don't think they are THAT sketchy (a new word for me). I'm OK with gloves, good ventilation and safety glasses - safety should allways be first.

    I really appreciate the opinion of @Mendel Leisk, but with Oxyclean (is it OxiClean?)
    I do have a problem - is it accesible outside of North America? It is a product - not a chemical, which I wanted to discuss and it needs a night long soak...

    And I think, a good discussion is never bad, even if we are discussing something, that appears obvious ;)
    I hope, I was clear enough in my initial post, about what and why I would be glad to dicuss.

    Mat
     
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah I think Oxi-Clean Versatile Stain Remover might be hard to find outside of North America. NaOH (sodium hydroxide, lye) is readily available, should be quite effective. Just need to be careful with it. Always add it TO water, not the other way 'round. Eye protection might be warranted, and for sure rubber gloves, a ready source of rinse water, and common sense.
     
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  5. Lares_Mat

    Lares_Mat Member

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    Te safety precautions are obvious, but mentioning them every time is not too much.

    NaOH should not harm PA6 (10% solution at room temperature), but what with the metal inserts in the intake manifold. If they are aluminium, it could afect them - no idea how qiuckly and how strong.

    Mat
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah only for EGR cooler.

    I merely used (milder caustic) oxi on the intake one time, regretted it: left the metal embeds with crusty corrosive film.

    same story for EGR valve, it’s mostly aluminum and will react with caustic.

    the pipe between valve and intake manifold is stainless steel, but trivial to clean, say with brake cleaner.
     
  7. Tombukt2

    Tombukt2 Senior Member

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    It's an intercooler so we can go to the radiator shop and be tanked clean it can go in the safety clean but I don't think they make the original green chemical anymore that stuff would eat your hands up and I like the smell of it but I take it over to the machine shop or the radiator shop and they'll tank it and get it silver generally speaking and it just is a few bucks and I don't have to dispose of anything or do anything crazy.
     
  8. ASRDogman

    ASRDogman Senior Member

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    A pressure washer will clear out the cooler. Oven cleaner will clean it out after soaking for
    30 minutes or so, and rinsing again with the pressure washer.
    Depending on how bad it is, it might take a few times.

    Don't use the oven cleaner on the aluminum or plastic parts.
    You can use Gunk cleaner, flamable one, not the usless foam version.

    I use a gun bore brush in a drill for cleaning out the egr ports on the intake manifold,
    spraying with gunk. It will clear and clean it in a few seconds.
     
  9. CR94

    CR94 Senior Member

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    Because many of those are primarily sodium hydroxide, NaOH.
     
  10. ASRDogman

    ASRDogman Senior Member

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    It doesn't matter what's in it, it works. I used it on my 2 Stroke RD350 to decarbonize the pistons.
    It worked great. And the pistons where aluminum. It didn't seem to hurt them. So many it's
    okay to use on aluminum???
     
  11. Lares_Mat

    Lares_Mat Member

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    On the contrary, it is very important which component does the job!
    Not everyone has te possibility to buy every product made in the US ;)

    It would be nice to know, what is the concentration of NaOH in the product and how long was it on the pistons.

    Mat
     
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  12. ASRDogman

    ASRDogman Senior Member

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    No, it does not matter what's in it. It works, that's all that matters.
    I might matter to YOU, but that's completely different.
     
  13. Lares_Mat

    Lares_Mat Member

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    Oven cleaners have NaOH very often on the list of ingredients beside of some solvents (ethers), ethylene glycol (like antiffreeze) and methylene chloride (dichloromethane, which was on my list).
    It will not harm the stainnless steel cooler and the steel pipe wich sits between the cooler and the intake manifold.

    RIGHT - definitely not for intake manifold or for EGR valve.

    It would be nice to know, what type of GUNK product exactly it was and what are the ingredients. Is it possible to get the ingredients list anywhere (I'm from Poland - didn't even know, there is someting like GUNK ;) )?

    Mat
     
  14. Lares_Mat

    Lares_Mat Member

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    I can undestand your point of view. If it is not a problem to buy some exact product, it does really not matter, what is inside.
    If you live outside of the USA and have trouble to get that product, or it has to be imported, payed for shipping and customs, it beginns to matter, what are the ingredients. You can then find something with similar ingredients in your region.

    Yes, it matters to me, while I'm not living in the USA.
    I think on priuschat.com there are more people like me.
    And maybe others would be glad to know, what really does the job - out of simple curiosity ;)

    Regards

    Mat
     
    #14 Lares_Mat, Aug 14, 2022
    Last edited: Aug 14, 2022
  15. Noahdoge

    Noahdoge Active Member

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    The SDS of my brake parts cleaner I used contains acetone, methanol, and toluene. It works very well for carbon.
     
  16. Lares_Mat

    Lares_Mat Member

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    Acetone seems to be a really promising chemical.
    It is widely accessible, apparently not that aggressive to the environment - you find it in almost every nail polish remover.
    I think methanol is here to dilute any oily residues, acetone dilutes resins, I think, and toluene is mentioned on many ingredients lists of cleaning stuff I saw (maybe replacing dichloromethane, which seems to be really nasty stuff, I did not know before).

    I found two films on youtube showing acetone in action on piston carbon deposits - really interesting:

    a short one
    a longer one.

    I'm not sure, why they are mixing acetone with transmission oil.
    Has it to be _transmission_ oil?
    My guess would be, to make it less volatile and more sticky - better for application, but then, every oil would do, wouldn't it?

    And our intake manifold plastic (PA6) seems not to be harmed by acetone, as you can see here on page 3:
    https://www.nylacast.com/wp-content/uploads/2019/04/NylacastChemicalResistanceTable19.pdf.
    Maybe you could even clean the EGR valve with it? Many use brake cleaner to clean the valve.

    Mat
     
    #16 Lares_Mat, Aug 15, 2022
    Last edited: Aug 15, 2022
  17. StarCaller

    StarCaller Senior Member

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    quote from bitog:
    "Before the 70's ATF was Whale oil which is an ester so I can see cleaning being accomplished by using it."
     
  18. Lares_Mat

    Lares_Mat Member

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    OK. I had to google both - the quotation (didn't even know what would be the "bitog") and the ATF (I am a non american species ;)).

    Found the quotation and grasped it.

    Then I read a little about ATF in Wikipedia.
    Found something like this:
    "Most ATFs contain some combination of additives that improve lubricating qualities, such as anti-wear additives, rust and corrosion inhibitors, detergents, dispersants and surfactants (which protect and clean metal surfaces);"
    and even a mention of whale oil was there:
    "In the 1940s, 1950s, 1960s, and early 1970s, ATF contained whale oil as a rust and corrosion inhibitor."
    So... ATF was not based on whale oil as lubricant - it contained whale oil as an additive.

    So much to clarify the poor whales role in ATF production ;)

    I can imagine a role the ATF could be playing in ATF-acetone mixture as it has additives to "protect and clean metal surfaces", but still... I think, it is mostly there to let the mixture stay in place and not evaporate that quickly, as acetone itself would do.

    Mat
     
    #18 Lares_Mat, Aug 15, 2022
    Last edited: Aug 15, 2022