Important update - airleak, head-gasket, water pump, P261B

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by kobear18, Oct 13, 2021.

  1. kobear18

    kobear18 Junior Member

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    Hi every1
    I got an important update for all of you who got similar problems. Its giving me P261B water pump code but I think its not its problem to begin with. My problem started last year around July with misfire and higher temp and also that P261B code. I asked around and thought that it must be head gasket problem so I got the Bar's Leak to seal it. Everything was fine until this May. I got similar problem again so I changed the pump and thermostat too. It worked fine until last week. It gave me that water pump code again. The symptoms that I see now is: it stays at higher temp even in maintenance mode. First 25 min is fine, after 25min, it stays at 195 to 220 and cabin heat loss after it past 195. I thought that is very strange. Cabin heat was there for the first 25 min no issues. I also saw bubble came from the lower hose of coolant reservoir tank. That only happened after 25min and over 195. So I thought it must be the head gasket again and it also fired the water pump. I took the water pump out yesterday and yes it was hard to pull that spindle out because there were some sealants around it. However, it turns fine except some scratch and scrap at the bottom of that spindle. I also thought that i may be the radiator was clogged too. I asked where the upper and lower hoses were so I can do the radiator flush. I was able to open the lower hose attached to the thermostat but the upper hose was a lil more difficult but I was still able to open it and flush through it. I did not feel much pressure flushing both hoses so I think the radiator is fine for now.

    I thought that the worst case is that I put a new pump on and use the head gasket sealant again since the radiator was not clogged. I was half way done installing the pump. I thought maybe I should tighten up the thermostat too just to give it a few more turns. Oh shit, that is where the problem was. I heard a snap sound and that fuking bolt broke off. Yes it was that bolt on the thermostat the only bolt hidden behind the thermostat. So now half of the bolt was left inside that hole. I bet it was this little bolt causing all the problems since last year. It was a designed flaw for the car to fail. Otherwise, nobody buy new car. The other 2 were nuts holding it. Why they wanna make the most difficult bolt there and it was so fragile.

    For the people who thought they got cracked head gasket, this may actually be the only cause. It was loosen just a lil bit to begin with. The Bar's leak was able to seal it. As time go by, that bolt is getting more and more damage until it finally just broke off. That is where the air come in at higher temp. Lower temp, the system was still be able to hold it. When it gets too hot, the housing at that loosen bolt opens up maybe just a lil crack to let the air in the system to cause over heat and bubble and fired the water pump a lil bit too. I should also mention that I heard screaming sound from either the water pump or it may actually comes from the thermostat.

    But anyways, I think this is IT !!. IT caused all these problems. Let me show you some pix. Now the problem is how to get that half broken bolt out of that hole ??? Weld it to some thing so I can turn? Welding cause a lot of money. Super glue ?? Doubt super glue would work. What kind of technician can get broken bolt out ?? Not necessary a auto mechanics know how to do that.

    It is a 10mm bolt but I don't know how long it is and the thread size. Too long or too short wont work, it has to be exact. Otherwise, it will be too loose if its too long.

    20211013_152221.jpg

    20211013_152422.jpg
     
    #1 kobear18, Oct 13, 2021
    Last edited: Oct 13, 2021
  2. kobear18

    kobear18 Junior Member

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    another pix
    20211013_152433.png
     
  3. ChapmanF

    ChapmanF Senior Member

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    Here is your bolt: 91551-80620

    You can probably find an M6x1.0 flange bolt (10 is just the size of the hex head) at the hardware store, but at only a buck or so at the dealer, you won't have to fuss about getting the length right etc.

    I'm not sure I agree with you a hundred percent on your policework there, Lou.

    When the engine is at operating temperature, the pressure inside the system is roughly one full atmosphere higher than the pressure outside. If that elbow were separating by just a crack then, outside air getting in is not what would be happening.

    I suspect all that happened to the bolt is you broke it off just now.

    Backing up in time a little, when you were getting those P261B codes, did you ever happen to watch the live data and see what water pump RPM you were getting?
     
  4. kobear18

    kobear18 Junior Member

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    Hhmm...i dont have fancy scan tool to get live data tho...im sure that bolt has been loosen for a while and it just snap today. Maybe at 200, 220 f the crack is big enough for air to come in. I only saw bubble after 25min and over 195, 200 ish...if head gasket cracked, it should have been earlier than that and white smoke at start but i dont see white smoke tho
     
  5. kobear18

    kobear18 Junior Member

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    I also forgot to mention....i loosen the coolant reservior cap too to bleed air out ..so that may cause lower pressure in the system. I know I have this head gasket problem so I usually dont close the cap tight.
     
  6. ChapmanF

    ChapmanF Senior Member

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    If the cap is left loose, the pressure is atmospheric, and there'll be bubbles from the coolant simply boiling around 225 ℉.
     
  7. kobear18

    kobear18 Junior Member

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    the big question is how do I get that broken bolt outa there ??? I just zoom in but there is not that much sticking out. Some suggest drill it and break it
     
  8. AzusaPrius

    AzusaPrius Active Member

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    By the time you would see white smoke out the tail pipe it is beyond headgasket, it has now killed your catalytic converter.

    In my case I never saw white smoke but somehow the catalytic converter went bad after replacing my engine.
     
  9. rjparker

    rjparker Senior Member

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    You need to use a reverse drill, one that turns counter clockwise (ccw) as you drill. Sometimes that bit will wind out the bolt. If that fails you use a screw extractor that also gets tight ccw. If that fails you drill out the bolt completely, ruining the block threads. Then you have to tap it out larger for a larger thread or use a special insert. If you have never done these things you might be better off letting an experienced shop do it.

    I agree with the above, white smoke is end stage engine failure in many cases. Fixing a head gasket quickly can save your engine.

     
  10. rjparker

    rjparker Senior Member

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    Sorry but they don't design to fail. Engineers are just like you and I, they make mistakes and the consumer pays the price. Toyota tries to do accelerated aging tests, they hold suppliers to high standards and dealers often make mechanics redo failed repairs at the mechanic's expense. If bolts breaking off the water pump was a design flaw, Toyota would typically pay for the fix even after the powertrain warranty. Parts do wear and fail, any machine at any price fails. A couple of space shuttles failed taking out their crews. Designed to fail? No. Design flaw? Yes.

    This along with the Bars Leak sealer pretty much verifies you have a head gasket leak. The sealer and reduced pressure helps, you got an amazing July to May reprieve. Most get one to three months.
     
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  11. kobear18

    kobear18 Junior Member

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    i dont see white thick smoke but maybe a lil bit when i suspected it was the head gasket last year. i applied the Bar's leak since last July. White smoke went away

    but that little bolt is small enough already. I need a very small reverse drill ... let me check

    update: I was still able to get the bolt out with a lot of patient. However, I just did a test run but still saw bubble and temp was still kinda high. At the beginning, there was heat but past 195 no heat. It is still a mystery. Maybe I just need to keep burping air out for now. I just turn off the car when it reach 208 and then turn on after a few hours. That is what the plan is for tomorrow.

    But is it possible that the radiator is 50% clogged? I tried to flush both lower and upper hoses, water came out from either way no problem. If its 50%, will the water still come out ok like it did? The thing is that there was not much water came out when I opened the drain valve (petcock). Does it mean there is no water in the coolant tank at the bottom? Maybe its the lower portion of the radiator is clogged?
     
    #11 kobear18, Oct 13, 2021
    Last edited: Oct 14, 2021
  12. kobear18

    kobear18 Junior Member

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    I agreed maybe I was lucky. From May this year, I did the same thing, replaced water pump and thermostat and it worked from May to now. Oh well, I heard that some people can still drive for a few years no problems. I just hope that at least let me get through this chip shortage so I can get a new car then.
     
  13. rjparker

    rjparker Senior Member

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    First 208F is not too hot. Do you have antifreeze in it? How hot does it get? Do both radiator fans run? Do you see coolant flow in the reservoir?

    You should get about 1-1/4 gallons out of the peacock. If not it is either already empty or the radiator among other things may be clogged up. When using block sealers in the past, most manufacturers required you to remove it quickly. There was a whole prep, use, flush and new antifreeze process. The newer magic in the can solutions are simply giving you fast results at the cost of a major long term expense.
     
  14. Mendel Leisk

    Mendel Leisk Sand Pounder

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    upload_2021-10-14_7-27-28.png

    Could you get a hacksaw blade (or dremel disc) on there, create a slot?
     
  15. kobear18

    kobear18 Junior Member

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    I already got it out by using those tools. I was lucky, it was NOT tighted at all 20211013_212030.jpg 20211013_212021.jpg
     
    #15 kobear18, Oct 14, 2021
    Last edited: Oct 14, 2021
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  16. kobear18

    kobear18 Junior Member

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    I also think that we dont need to get to the lower hose of radiator to flush the system. The lower hose of the expansion tank is enough to do the job. If I feed water into the lower hose of expansion tank, water goes into the radiator reservior then some water goes to lower radiator hose then to the engine block and come out to upper radiaor hose and some other water goes to the tubes of radiator and into the engine block from the upper hose. If I open the petcock, water go out from there. Some water may even go back to expansion tank from the upper hose of the expansion tank. I think now I got a better picture of how n where water goes in the entire cooling system.
     
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