high engine coolant temp, no heat in passenger cabin

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by dlenox, Mar 13, 2016.

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  1. dlenox

    dlenox Junior Member

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    all,

    have searched a LOT of the articles pertaining to this situation, still having issues.

    first background: G2 car has 215,000 mi and recently got P1121 scan code, so I replaced the coolant control valve. that's when high coolant temp and no cabin heat started.

    on CCV top nipple connected to hose that had a dot on it and hose goes under inverter cover on right, next nipple down went to hose slightly to left of first hose, bottom hose goes to thermus can. initially ran car in diag mode with high heat, no heat in cabin.

    so I got a Autel 519 scan code reader and I see now that the only code is a P0505 (idle air control malfunction)

    taking car down my road for short test run, I turn off cabin heat completely and watched the ECT. after a while it climbs to around 220, then while engine is running quickly goes to 245F then 260F.
    at that point in time (around 245F) the high temp indicator lights up, temp stayed at 260ish so I return home.
    with car in park, cabin heat off - the temp returns back down to 220F. if I rev the engine temp again climbs.

    I have gone through all suggestions, open radiator bleed valve, manually 'pumped' coolant hoses, turned on/off high heat in cabin and finally with car off removed and jumped the CHS multiple times for about 20secs.

    Have purged the coolant system over period of days and coolant appears to be full as level is near top of radiator cap, no bubbling, no gurgling.

    However 2 mentioned problems continue... I am starting to suspect coolant thermostat but it would seem strange that it would go at precisely the same time as coolant control valve.

    Have appt at dealer, but it is 60mi drive and feel uncomfortable with the drive when temp stays high, so unsure if it is ok to drive at this point.

    Pretty much at end of my wits and looking for suggestions.
     
    #1 dlenox, Mar 13, 2016
    Last edited: Mar 13, 2016
  2. exstudent

    exstudent Senior Member

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    Any part can fail at any time. It could be just coincidental that the thermostat failed while changing the 3way valve. If it indeed fail, isnt it best that it failed at home vs a road trip 100s of miles away from home?

    Why not just remove the thermostat and test it to confirm. Its a $16 part at Camelback Toyota.

    Maybe you reattached the hoses incorrectly?
     
  3. jadziasman

    jadziasman Prius owner emeritus

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    Clogged radiator can cause this. Radiator cooling fan not functioning can also.
     
    #3 jadziasman, Mar 13, 2016
    Last edited: Mar 13, 2016
  4. dlenox

    dlenox Junior Member

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    I used new SLLC coolant and fan appears to 'kick in' at about 205F.

    Actually the P1121 alarm threw about 100 mi from home, took it slow and limped my way back. Travel up mountainous road capped speed at about 35mph.
     
  5. exstudent

    exstudent Senior Member

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    Now I remember. P1121 will cause the heater to not work b/c valve can be stuck in wrong position. This 3way valve won't cause the car to over heat, but misery in winter.

    Rule out the thermostat. If it passes, then you may have blockage.
     
  6. jadziasman

    jadziasman Prius owner emeritus

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    Whatever you do, don't drive it to the dealer if it continues to overheat like this - you might blow the head gasket (if you haven't already). Transporting it on a flat bed or with its front wheels off the road will be expensive but will be less so than replacing your Prius altogether.
     
  7. dlenox

    dlenox Junior Member

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    I think I finally figured it out - I looked at where the grooved belt that drives the water pump and IT IS NOT THERE!!!

    that explains how NO water is being circulated.

    does anyone have good pictures and procedure on how to replace?
     
  8. exstudent

    exstudent Senior Member

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    Water pump belt replacement has numerous threads. Search w/in PriusChat or use Google.

    While you are at it, maybe address other maintenance items the car is lacking.
     
  9. jadziasman

    jadziasman Prius owner emeritus

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    Well, that's great news. I'm surprised you didn't hear the belt snap while you were driving it at 35 mph after the P1121 code was triggered.

    Many Toyotas of the early to mid 2000s had crankshaft driven water pumps unlike the timing chain/belt driven water pumps in Hondas and others.

    Here's a great YouTube video that shows how to replace the drive belt as well as the water pump. You will need to slow the video down to see how the belt is released.
     
  10. 69shovlhed

    69shovlhed Surly tree hugger

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    the belt is very easy to replace, and it is possible you can push the new belt on without even having to adjust the tensioner. do not drive without the belt. don't even run the engine without the belt. you will blow the head gasket or worse.
     
  11. dlenox

    dlenox Junior Member

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    Thanks for the link, I replaced the belt today and got it tensioned, was actually pretty simiple and easy to perform.

    This is definately something to check, unfortunately with the P1121 alarm I was focused on the OTHER side of the engine compartment.

    At the time that I lost the belt I was accelerating onto highway, at the time I thought I heard something, but rationalized that it was a bump or something, then alarm started sounding off. Luckily for me that day it was relatively cold out (about 35F) and it appears (so far) that no damage was done to possibly warping head from heat.

    Actually up till a week ago I did not know that the Prius had ANY belts. Silly impression now that I know that there is a single belt - and it drives the water pump.

    All's well that ends well, now getting back to attempting to get to 300,000 miles!
     
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