I have a 2006 Prius with 147k miles. A noise is coming from the ICE, both warm and cold. Quiet at idle and low rpm, but sounds like a valve tapping under moderate to heavy acceleration or a nasty fluttering tap when accelerating uphill/higher rpms. In park, revving the engine does not produce the noise. Any ideas? I'll try and get a video of the sound soon.
It's been making the noise since I bought it about 5k miles ago. When I bought it I replaced the hybrid battery and did normal maintenance, fluids and spark plugs. It wouldn't run at speed due to the battery issue when I bought it so I didn't hear the noise before hand. It's not horrible, but any noise is of concern to me. Just sounds like a bit of mechanical chattering. Only really noticeable at high rpm/load. Running mobil1 high mileage 5-30.
You shouldn't hear any valve noise when accelerating. Mine is very quiet. But with hood open and the engine at idle its a pretty loud clakity little motor as it uses solid lifters. I recommend you do a little investigation. Go on youtube and find PRIUS INSPECTION MODE. It's a series of simple button pushes that puts the car in an engine test mode and the engine will idle for hours until you shut it off. With the engine idling unattended listen around the motor. Get under the front of the car as deep as you can and listen real closely to the bottom of the motor/oil pan for lower end noise like thumping or loud tapping. That's a lower end bearing failure. Those are caused by running the engine dry of oil. Seen alot of these here lately. Blown motor. Very few complaints of valve noise. Its a pretty good motor basically trouble free but will not tolerate running low on oil even just once. And go to toyota.com/owners and join and list the cars vin. It will show you every time the car has seen an authorized Toyota dealer for service and may give you some insight into why it was sold. Btw, is this a salvage title car?
What was the resolution to this? My 2009 is making a similiar noise. It happens when I floor it or resuming a cruise control speed.
Quoting 2 year old post. But didn’t quote anything I asked. Engine noise is caused by 2 things mostly. One is letting the engine run so low on oil it throws a check engine light or red triangle which usually damages the engine or it’s low now Or The hybrid battery is failing and not contributing its usual power and now since it’s missing its power contribution you have to floor it to achieve the same acceleration power. Without solid hybrid performance it’s a very anemic car as it relies on the little 90 horsepower engine. How many miles?
Any chance this is detonation resulting from a clogged EGR cooler? I was just reading about that in another thread.
Sorry gang but I ain't buying the EdTheFox explanation. I'm hearing of several Prius' with valve clatter or detonation. Mine is a 2006 at 280,000 miles. It's definitely not due to the battery because if the battery lost any ampacity below and family data then you will get the red triangle. I would love to know why these blog threads seem to be cut short of the true answer. The threads just seem to stop with no conclusion Posted via the PriusChat mobile app.
There is no mechanism to force any contributor to follow up or give closure. It can be frustrating but it's the nature of the beast.
Do you have a brand new (not refurbished) battery? The batteries tend to have less capacity when they get older, you don’t get the code when the capacity goes to 99% of new. Your battery could have 50% capacity of new and still have no codes. It sure would not preform like it did when it had 100% capacity though.