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2005 Prius Coolant Loss

Discussion in 'Gen 2 Prius Main Forum' started by buddy77, Jun 21, 2010.

  1. buddy77

    buddy77 Junior Member

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    Vehicle:
    2006 Prius
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    2005 Prius...113k miles...master warning light & a coolant temperature briefly light up several times while commuting. The inverter coolant tank stays full, but the motor coolant is empty every day after a 30 mile commute. I fill it up & 30 miles later it is empty. There are no puddles or evidence of a leak while parked in the garage. Any help as to what the problem may be?
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Two
    1. Check the engine oil dipstick to see if the oil looks nasty (i.e., coolant in the oil).

    2. Remove the black plastic cover over the radiator to gain access to the radiator cap. Open the cap (when the radiator is cold) and look inside. Do you see evidence of oil in the coolant?

    3. When the powertrain is warmed up, floor the accelerator pedal and look in the rear view mirror as the car takes off. Do you see any visible exhaust (white smoke for example)?

    If you don't see any problems with 1-3 above, then use a trouble light or flashlight, and examine very closely the radiator, hoses, and the engine looking for a coolant leak. Leaked coolant will typically show a whitish or pinkish stain. Good luck.
     
  3. Nate Glenney

    Nate Glenney New Member

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    I'm having the same problem with my 05. We use ours as a fleet vehicle with our taxi company and the 05 is at ~167k miles and my driver noticed that her reservoir was empty a couple days ago. She called me in concern and I asked if there were any puddles under her car. She said there was no visible leakage whatsoever underneath her car (I then asked her husband to verify and he had the same remark). I had her go to the auto parts store and buy a jug and walked her through filling the reservoir and told her to drive it around for about 20 minutes and check it again. She did and said the coolant was still full. The next day (about 260 miles later) she noticed that it was low again. At this point, I assumed the worst and told her to come to the shop and swap out into our 07 Prius. After we had that taken care of, I changed the oil to check for coolant presence in the system and performed a block seal test with the radiator, however neither test yielded any sign of a bad head gasket (my original fear.) I'm not by any means an expert on Prius' (or any hybrid for that example) so I'm not sure if there is any other accessory in the vehicle that taps into the coolant system that could be losing the fluid, but I've exhausted all basic/intermediate tests for coolant loss. The only thing I haven't tried is a vacuum test for a cracked head.
     
  4. Nate Glenney

    Nate Glenney New Member

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    Vehicle:
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    Another point I'd like to make is that my 05 burns a LOT of oil between our regular 5k oil changes (between 2-4qts). As a result, or so I believe is a result, I've been getting an intermittent p0420 code, pointing towards the cat. converter running inefficiently. I'm assuming that in the life of the vehicle and the massive amounts of oil that it has burnt that the system has become inevitably plugged up. Its also showing a significant drop in economy (about 10mpg). Could this be a factor in the coolant loss or am I just getting desperate for an answer now? Haha

    Also, we have 2 other 07 models, and one of which is approaching the 200k mark and has never experienced any issue with the coolant/cooling system. It also, however burns quite a bit of oil (not nearly as much as the 05 but more than I'd like to see.