PriusOnline.com

Hi all,

2006 Prius - 91K miles. This noise became apparent when I changed tires (the old tires were getting loud and were masking this noise.) I swapped the new tires left<-> right and the noise stayed where it is. It becomes apparent at 35 mph or so and is unrelated to engine operation i.e. put the vehicle in Neutral or P&G-coast and it still whines. I'm thinking wheel bearing - any opinions or other ideas?

Coincidentally I am scheduling dealer maintenance (a rare event for this car as it's a "big deal" for us to make a trip to the closest dealer.) The items on my list so far are:

- inspect tappets
- transmission oil change
- motor and inverter coolant change
- spark plugs
- PCV
- any belts
- wheel bearing (?)

What else should I consider? Do these engines use a timing belt that needs replacement?

thanks,
Frank

This is all you need to do at the 90K service http://smg.toyotapartsandservice.com/ws ... =18&done=1

Tell the dealer about the noise. It could be a wheel bearing or some debris caught between the rotor and the brake pad.

Hi, Frank,

Your 2G Prius ('04 through '09) uses a timing CHAIN in the engine for more dependability. However, I don't know if the "Classic" (2000 through 2003) or the 3G (new 2010 model) also make use of a timing CHAIN. Maybe someone else here with more knowledge will set me straight.

Ah Hah! A chain - that's why I can't find any replacement info on it. It should last forever.

I'm bringing the car in tomorrow; it's never had the ATF or coolant changed and is due. I'm also having the alignment checked even though it tracks straight; my last set of tires did have a slightly strange wear pattern. I just installed some Goodyear Dura Fuel Max (?) tires and can already see an improvement in my regular driving route.

thanks for the info

BTW, apparently there are no tappets; see post #16:
http://priuschat.com/forums/gen-ii-priu ... post932001

Since you have a 2006 Prius, this is an aside that won't help you, but the classic Prius (up through 2003) has a timing chain, too.

As for the whine, our 2002 Prius makes a whining noise at a specific speed (can't recall, but I think it's about 40-45 mph) that comes out of the hybrid module. It's not noticeable with the air conditioner or heater running, or when not driving at that speed. But, when I've got the windows down, you can hear it pretty good. In this case, it is probably a transformer or large capacitor "singing", because there is so much power going through there. But, it hasn't affected the reliability; we just passed 100,000 miles.

Did the plastic strip come off the underside of the outside rear view mirror? If there are holes and exposed screw heads on the bottom of the mirror, put a piece of tape over them and see whether the mystery noise goes away.

Well, a lifter is a tappet. It sounds like it's similar to many motorcycle systems where the camshaft/valve clearance is controlled by changing a bucket shim (it fits over the valve stem.) Clearances were checked but I don't think anything needed adjusting. Anyway, the dealer changed out the coolant (engine and inverter), changed ATF, replaced a defective wheel bearing and water pump (weeping seal) under extended warranty and verified alignment. I asked them to check the serpentine belt which they suggested be changed (as the old one had to come off when changing the water pump anyway) and also the spark plugs. Toyota recommends 120K miles for plugs but I had them done anyway. Old plugs can start to corrode in the head but these came out fine. As far as I'm concerned this car is good for another 100K miles!

Could be the inverter coolant pump about to die. It's behind the driver's side headlight assembly, and is a known problem in 2004-5 and early 2006 Prii. Mine failed (2005) at 54,740 miles. If you Google "prius inverter coolant pump" you'll be able to spend a couple of quality hours learning about this critical component. If it fails, it's serious, so it's worth considering a proactive replacement if it sounds like it might be failing. Toyota TSB EG001-07 applies. If it fails, it's covered under the 60 month/60,000 mile powertrain warranty, but I guess it'd be up to your dealer to decide if the warranty would cover replacement before it fails.

Just reread your OP, noticed that you're out of warranty. But if you're having the coolant replaced, this would be an excellent time to replace the coolant pump, if your s/n is one of those affected by the TSB. s/n or not, though, I'd have the dealer check the coolant pump.