Throttle Body Clearning-Remove or Not

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Sanchan, Apr 29, 2021.

  1. Sanchan

    Sanchan Junior Member

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    Hi Guys! I am thinking about cleaning throttle body of my 07 140k miles. I checked out many thread here and you tube video as well. I saw one video that the owner actaully remove TB and clean it instead of cleaning from the top! Is there any benefits for doing this way? Have you done it this way? Your thought?
     
  2. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Lift it off and leave coolant lines attached. Not at PC right now, but if sim to 3rd gen there’s 2 bolts and 2 nuts holding it down, and torque 7 ft/lb (in a crisscross). Clean as much of intake manifold underneath as you can reach too.

    Addendum:, see update in post #6 below.
     
    #2 Mendel Leisk, Apr 29, 2021
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  3. Sanchan

    Sanchan Junior Member

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    Thank you for your reply! So you recommend this way(removing) rather than cleaning from the top like many owners have done?
     
  4. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Much easier and more effective, having it in your hands and both sides accessible. You might want to spring for replacement gasket, depending on age/condition. Use carb cleaner sprayed on cloth or q-tips.
     
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  5. Sanchan

    Sanchan Junior Member

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    Thank you so much! I will do it that way! I am ordering TB&Air Intake Cleaner and MAF Sensor Cleaner along with a new PCV valve(I might as well take care of this while I am at)!
     
  6. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Attached is 2nd gen repair manual excerpt: it's a single bolt and two nuts, and torque is 15 ft/lb.
     

    Attached Files:

    #6 Mendel Leisk, Apr 29, 2021
    Last edited: Apr 29, 2021
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  7. Sanchan

    Sanchan Junior Member

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    Thank you! This helps a lot! One more question? I am assuming that I can do what you have suggested(post no. 2)since I am not draining an engine coolant, right? But If I want to remove TB completery(disconnecting No1 and 2 water by-pass horses), intial engine coolant draining is a neccessity? Can I possible disconnect water by-pass horses without draining coolant intially and breeding the system later?
     
  8. ChapmanF

    ChapmanF Senior Member

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    Might not be able to breed the system later, unless one of the by-pass horses is a mare and the other isn't.
     
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  9. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Not sure.
     
  10. Sanchan

    Sanchan Junior Member

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    Thank you guys! I really don't wanna deal with a coolant issue so TB will be lift with by-pass water horses(and two electricals connectors)attached! It should stll give me enough space to clean it well!
     
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  11. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Yeah I’ve done this in n 3rd gen, hopefully doable on 2nd. If there’s a decent amount of slack on the coolant lines you don’t want to disconnect them.
     
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  12. Sanchan

    Sanchan Junior Member

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    I found you tube video from Japan and he was doing that with his Gen 2. He also decided not to disconnect by-pass water horses but still have enough space to clean TB and intake of surging(?) tank. I think I should be able to do the same! Thank you for your help!
     
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  13. edthefox5

    edthefox5 Senior Member

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    Yes go to the dealer and get the little gasket first. You live in Ca why don't you bypass the coolant to the throttle body why your at it?

    I did that to my bought new 07 about 2 weeks after I bought it. Its a good well known mod the car will be peppier and the throttle body motor will last much longer without constant 180 degree heat going through the body. Coolant loop is only needed in cold climates to stop vapor lock.

    The throttle body will never get hotter than 90 F with the coolant bypassed. All you need is a 3/8 PEX barrel and 2 small hose clamps and barrel the hoses together. Its wicked easy you wont lose any coolant. My G2 loves it never ever any issue.

    Mines been bypassed 14 years. Car runs great its been running so good I put a red bullet on it too thats alot of fun. One bolt install and very peppy.

    Google: Throttle Body Coolant bypass

    Also pull off the 2 black hoses that plug in on the top of the TB make note of there positions. Look at the ends see how gunked up they are. One is the pcv outlet the other is crankcase return they both go the drivers side of the valve cover. If the hose ends are really sludged up the pcv valve should be replaced.
    Its been a while i think the pcv valve hose is on the back of the tb. I think. Its the one really sludged up.

    The sludge or lack thereof is a direct result of the oil quality your running.

    With the hoses off flush out the inlets on the TB there connected too.
     
    #13 edthefox5, Apr 29, 2021
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  14. ChapmanF

    ChapmanF Senior Member

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    Icing would be my guess ... vapor lock being more of a thing from the days when the fuel pump was on the engine instead of in the tank.

    I'm not sure what the ambient has to get down to for throttle body icing to be a thing. Expansion and evaporation will cool the intake air by some amount when it gets sucked past the throttle at low-load conditions.

    Checking the New Car Features manual ... yup, the Gen 1 book says "A warm coolant passage is provided below the throttle body to prevent the throttle valve from freezing during cold temperatures." (p. 55)

    Edit: hmm, this source says the cooling due to air passing the throttle valve tends to be around 3 ℃, so temps 0 to 3 ℃ (32 to not quite 38 ℉) are where it gets interesting. That source is for aircraft. This one looks directly on point for auto engines, for readers with SAE access.
     
    #14 ChapmanF, Apr 29, 2021
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  15. Sanchan

    Sanchan Junior Member

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    Forgive me for my ignorance. I did not know anything about this by-pass horses and what it does until you just mentioned to me. I am googling to understand more. But it sounds fantastic! I am assuming(please correct me if I am wrong..)barrel horses together and plug those two by-pass inlets of the throttle body will not activate "warning" on dash board? Also, will it affect the result of smog inspection(I know this is California thing...)? Thank you so much for providing new knowledges! BTW, I do plan to replace PCV valve while I am at it. The car has 140k miles so I figure I might as well replace it. lol
     
    #15 Sanchan, Apr 30, 2021
    Last edited: Apr 30, 2021
  16. Sanchan

    Sanchan Junior Member

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    It does not happen often but once in a while, it does get to the range even in so called Sunny California. @edthefox5 stated that throttle body still get up to 90 degree F without by-pass horse connected it so I am assuming(correctly or incorrectly..)it is still ok? Regrettably, I don't know much about this subject and I am in a process of researching further. Any suggestions and advice will be highly appreciated. Thank you!
     
  17. ChapmanF

    ChapmanF Senior Member

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    I'd probably start by checking if there's any library nearby that has free access to that SAE article in the last link there.
     
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  18. Mendel Leisk

    Mendel Leisk Sand Pounder

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    OP’s original quest was cleaning throttle body; now he’s been distracted by coolant hose delete. Fugedaboutit?
     
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  19. Sanchan

    Sanchan Junior Member

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    Haha, I know I have an attention span of kitty lol It has been very educational and I am enjoying this! Is it so great you guys know so much and willing to share your knowledge with me. I have a little bit of motorcycle wrench experience but never really dealt with cars so this has been great! I love Pri-Chat! Thank you guys!
     
    #19 Sanchan, Apr 30, 2021
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  20. edthefox5

    edthefox5 Senior Member

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    He better not be distracted he's going to have to take the coolant loops off anyway to get the throttle body out of the car.

    You don't need to take the throttle body off to clean it but if he wants to good for him. You can probably do a much better job of cleaning it by doing that. Its easy. I have that little gasket was going to do it at one point but the engine is running so clean my TB has been spotless.

    If he's capable of removing the TB he's sure capable of connecting 2 little hoses together on a barrel. In fact he found my original post 14 years ago on this site with a picture of the connections. Good Job Sanchan!!!

    Post was called TB Hot Water Bypass.

    I think you called me a heretic on that post too as you often do Mendel lol...

    Car runs so much better and a very very cheap instant CAI. Just cant do it if the car see's winter temps. Im talking really cold like in the 20's.
    It gets really cold here once in a while we saw alot of high 30's this year and the car has never had an issue.

    YMMV.
     
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