A belt on the engine??

<div class='quotetop'>QUOTE(partipilo @ Nov 1 2007, 11:30 PM) [snapback]533748[/snapback]</div>

There is just one. It goes around the crankshaft pulley, the waterpump pulley, the power steering pump pulley, the alternator pulley, the a/c compressor pulley, and a couple idler pulleys (this is a 4.0L Jeep I'm describing, not a Prius).

 

<div class='quotetop'>QUOTE(partipilo @ Nov 2 2007, 04:00 PM) [snapback]533748[/snapback]</div>

There is just one serpentine belt, it drives the water pump, alternator, power steering pump and air conditioning while it spins a couple of idlers, one which applies tension to the belt.
(didn't see previous post before writing this.)

I have a policy on my vehicles, I replace the drive belts at 100,000km (While I change the timing belt if there is one) and keep the old belt for a spare which means I will never need a spare. :blink: At the first sign of a coolant hose deforming I replace all coolant hoses and flush the system. This I do on my cars, if you try recomending that in the trade you would be accused of over servicing. The replacement of belts in probably overkill as the new multi rib belts show signs of wear long before they break but I like the peace of mind. I only use genuine Toyota belts, there is a small price penalty but genuine belts are quieter than any other belt I have found.

 

<div class='quotetop'>QUOTE(seasalsa @ Oct 22 2007, 12:53 PM) [snapback]528950[/snapback]</div>

Ahhh, that explains it. I just started running the heater in the AM, and have noticed the SOC going down faster. I knew the engine had the belt-driven water pump but wondered what happened when the ICE shut down... in the summer without circulating water the water in the block might flash to steam even while pressurized.

So with the heater on in the morning, you might be running BOTH the AC compressor and the electric water pump. And because its cold the ICE will come on more to keep engine/cat hot. And lately its dark so the headlights are on. I wonder what's worse on mpg... winter or summer? This car has the complexity of a space shuttle. I better go check my O-rings. :blink:

 

I have an additional question. My belt is off as the water pump failed and threw the belt. I am just about to go out and replace the water pump. I am not sure of the routing although it does seem pretty obvious. Any confirmation of routing would be appreciated. This is a 2005 Prius.
Thanks for the assistance

 

The belt should go around the crankshaft pulley and the idler pulley. The outside of the serpentine drive belt should contact the water pump pulley.

3 bolts and 2 nuts hold the water pump to the engine; 8.1 ft.-lb is the tightening torque. You will also need a new water pump gasket.

3 bolts hold the water pump pulley to the water pump; tightening torque is 11 ft.-lb. You'll need to devise a tool to hold the pulley stationary while tightening the pulley bolts.

When depressing the new belt halfway between the crankshaft pulley and the idler pulley with a pressure of 22 lb, the belt should deflect 0.35 to 0.47 inches. I suggest you use a new belt even if the old belt was not lost.

 

Thanks for the assist. That is what seemed the most likely routing. I also appreciate the torque figures.

 

According to the service manual, to replace the belt, one removes the plastic cover on the drivers side under the car. Is this really necessary? One would think that the task could be entirely accomplished from under the hood...

 

Are you sure you're not mistaking the mechanical fan clutch which is bolted to the front of the water pump pulley?

On edit: I guess I was replying really really old post.

 

Yes, it would be helpful to remove the engine under cover on the passenger side (for left hand drive cars) so that you can run the belt around the crankshaft pulley.

 

The efficiencies of air cooled engines drops dramaticly compared to water cooled due to a number of causes..

Maintaining precise temperatures is much easier with water cooling, which allows cylinder head peak temps to be higher since water cooling can be relied on for precise and accurate cooling of areas operating close to maximum temps without mechanical damage. Peak combustion temperature is a significant factor in combustion efficiency.

Ring and piston clearances must be greater in air cooled engines, for the same reason,since air cooling can not be controlled as precisely.

Noise is much higher since finned surfaces designed to be efficient heat radiators are also effective noise radiators..