A belt on the engine??

<div class='quotetop'>QUOTE(partipilo @ Oct 12 2007, 03:48 AM) [snapback]524487[/snapback]</div>

isnt that the serpentine belt for Water Pump, Compressor And Idler?

i thought the air conditioner pump was in front of the radiator, and you wouldnt be able to see it
unless you took that big plastic piece off

 

That belt drives the water pump.
Because the AC is electric the idler is there to allow the belt to be adjusted.

 

Toyota has not yet concluded that it would be cost-effective to replace the (mechanical) engine coolant pump with an electrical one. Even though this would eliminate the thermostat and one crankshaft seal. I have long thought they should do it the other way, but my opinion in these matters does not count for much.

 

Hi Toch...,

That pulley has a harmonic balancer in it. So, one probably could not get rid of the seal. The balancer is a device which damps vibrations in the crank shaft.

 

There also needs to be a means to turn the crankshaft when performing some service and repair proceedures such as adjusting valve clearances. Therefore having the crankshaft coming out the end of the engine has it's advantages. Pitty about the power robbing belt. Shame Toyota couldn't run the pump off the timing chain and leave off the belt.

The water pump in modern engines moves water around the block even when the thermostat is closed to maintain even temperature through the engine. An electric pump would need to run almost all the time to achieve this anyway, unfortunately.

 

<div class='quotetop'>QUOTE(partipilo @ Oct 22 2007, 10:29 AM) [snapback]528805[/snapback]</div>

Many modern engines power the water pump from the timing belt, so you still have a belt. It really sucks when you need to replace a timing belt driven pump.

Tom

 

<div class='quotetop'>QUOTE(patsparks @ Oct 13 2007, 06:49 AM) [snapback]525076[/snapback]</div>

Actually the Prius has 2 water pumps, ref.DENSO
"The Prius's main water pump loses its source of mechanical energy when the vehicle is running on battery power alone and the engine is off. So, we developed an auxiliary electric water pump for the car. Our electric water pump provides a constant flow of heat to the cabin even when the mechanical pump is stopped. The mechanical pump operates when the engine is running, which reduces the load on the battery. And a bypass function reroutes water flow to avoid resistance from whichever pump isn't running."

 

I wonder if they could make it an air cooled engine?

 

<div class='quotetop'>QUOTE(partipilo @ Oct 22 2007, 07:29 AM) [snapback]528805[/snapback]</div>

I'm quite sure you're mistaken. Every Jeep with the 4.0L I6 engine that I've seen (and I've seen them all from 1992 until they stopped making them) has the water pump driven by a pulley, which also has the fan clutch mounted to it.

Think about it, the water pump is mounted up (relatively) high on the engine. That's not where the crankshaft is located. And it bolts to the front of the block, not the crankshaft.

 

Air cooled engines are generally noisier. Even motorbikes use water cooling which although it helps maintain finer control of the engine temperature to produce lower exhaust emissions the other function is to allow them to operate withing ever tightening noise control requirements.
Air cooling would not allow the degree of temperature control or noise supression to make the Prius acceptable. Can you imagine a VW engine starting and stopping depending on the demands of the HSD? Silent to rattle-trap in an instant.

Here is an image of the front of an i6 engine, the waterpump pulley is the big one in the middle. Your prius has 3 pulleys, crankshaft, waterpump and 1 idler, would you rather have the same belt drive as the i6?

 

Well in 20+ years in the trade I have never seen any car with the waterpump bolted directly to the crankshaft but I guess Chrysler may have made a 1 off.

The harmonic balancer bolts directly to the front of the crankshaft, that is the big pulley at the bottom and it drives everything else through the belt. They do fail from time to time.

 

<div class='quotetop'>QUOTE(seasalsa @ Oct 22 2007, 02:53 PM) [snapback]528950[/snapback]</div>

No. The Prius has four coolant pumps: three for the engine, one for the inverter/transaxle cooling system.

Engine: (1) mechanical main pump, (2) electric coolant heat storage system pump, (3) electric heater core pump.

 

<div class='quotetop'>QUOTE(patsparks @ Oct 24 2007, 03:15 AM) [snapback]529616[/snapback]</div>

He doesn't know what he's talking about. I've worked on '93, '94, and '95 ZJs with the 4.0L I6, and still own a '93 ZJ with the I6. The water pump mounts to the block above the crankshaft pulley, and has its own pulley. I've replaced the water pump twice on my own ZJ.

Here are a couple drawings out of the shop manual for the '93-'95 ZJ. It clearly shows the water pump mounted on the block above the crankshaft, with it's own pulley, and the belt routing shows the pulley for the water pump above the crankshaft pulley. The claim that it is attached directly to the crankshaft has to rank as one of the stupidest things I have ever read.

 

I was being polite.

 

<div class='quotetop'>QUOTE(patsparks @ Oct 28 2007, 12:00 AM) [snapback]531442[/snapback]</div>

Don't you hate it when that happens.

Tom