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Faint sweet/hot plastic/coolant smell 2009 Prius (2 year old)

Discussion in 'Gen II Prius Care, Maintenance and Troubleshooting' started by 2009Prius, Mar 29, 2011.

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  1. 2009Prius

    2009Prius A Wimpy DIYer

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    Today while driving to work I noticed this faint sweet smell that seemed like antifreeze. After parking I opened the hood and felt a similar sweet/hot plastic kind of smell. I looked at the engine coolant reservoir and the level seemed OK. I forgot to look at the inverter reservoir. Could a 2 year old car already develop coolant leaks such as pin holes in the cabin air heater core? Does this has anything to do with the possible timing chain cover seal leak? Any suggestions? I am not 100% sure it is coolant smell. Thanks!

    Update: dug up a related post: 2006 Prius reported end of 2007:



  2. edthefox5

    edthefox5 Senior Member

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    I can garantee you if your smelling coolant your leaking somewhere. If not readily visible most likely its leaking out of the ENGINE water pump weep hole. Get a flashlight and look closely in there.
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  3. 2009Prius

    2009Prius A Wimpy DIYer

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    Thanks I was wondering about that too. Where exactly is the hole? Do I look from above or from below? Which side of the engine?
  4. edthefox5

    edthefox5 Senior Member

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    Its right underneath the pump where the pully stem meets the engine. If your smelling it I bet you will see signs of water leakage on the belts and surrounding area. If not there jack the front end up and look under there real carefully for signs of leakage.
    Seems like there's a lot of posts about engine water pump replacement.

    Hope its not the heater core in the cabin. But its pretty stinky if you have a cabin leak.

    How many miles?
  5. 2009Prius

    2009Prius A Wimpy DIYer

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    18K miles. Thanks again!
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Feel the carpet on the front passenger side to see if it is damp.

    If you smell a sweet odor inside the passenger cabin then it is a reasonable bet that the cabin heater core is leaking antifreeze. That stuff is poisonous so I would not want to continue breathing it indefinitely.
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  7. richard schumacher

    richard schumacher shortbus driver

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    Get thee and thine to a dealer. Put that factory warranty to work.
  8. 2009Prius

    2009Prius A Wimpy DIYer

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    Update: It may very well be my own nose malfunctioning. Yesterday I kept smelling the same sweet smell in my office, on and off. On the trip home and trip to office this morning, I turned the heat off and on and did not smell anything different and no sweet smell. I put my nose close to the vent when the heat was on and only smelled dry warm air (coolant was high 180s to low 190s F). The front passenger carpet was dry. I haven't looked under the hood yet but since the smell is gone I am not too worried. Thanks again for helping!
  9. uart

    uart Senior Member

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    It mightn't hurt to see if there is any smell coming from the rear battery cooling vent. I've never personally experienced it but quite a few people here have reported a strange smell that originates from rubber vent tubes in the traction battery pack.
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  10. 2009Prius

    2009Prius A Wimpy DIYer

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    Today while driving I smelled a strong puff of sweet coolant smell, then it dissipated away. It was sunny and pretty warm inside the car and the heat was definitely not on (fan was blowing cool air, A/C was off). After arriving home I popped open the hood and it seemed to smell faintly around the engine coolant reservoir but not sure. I looked around for pink residue but can't find any. Levels in both reservoirs were fine. But it should be coming from the engine compartment since the heat was not on. Then the strangest thing happened that later when I biked with one of the kids to a neighbor's house I smelled the same thing briefly again. Could it be something in the air like some kind of flowers?
  11. xs650

    xs650 Senior Member

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    Coolant leaks that give off a little sweet smell can be hard to find. It takes very little coolant to make the smell so your coolant level might not visibly change for a long time. If the leak is under the hood, the leaked coolant may dry before you have chance to see it.

    One way to find small leaks like that is to wrap a bit of toilet paper around connection, or under weep holes. You will be able to see that the paper got wet by the way it is distorted, even if it's dry when you look at it.
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  12. googrx

    googrx New Member

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    I have experienced the smell before, right after I did the recall. Apparently, there were splash of coolant all over the engine and the container. I have it checked with dealership and they said it fine. I guess, technician or somebody open the coolant cap while engine was still hot?
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