Hmm my water pump failed again!!!! Could it be the pulley?!?!

[severous01]

does the oem pulley have a rubber ring in it? a dampner?

if it is, then the NST doesnt have a dampner. every time the pulley hits TDC or BDC you're slamming the pulleys on all devices and as the pulley rotates towards bdc or tdc the pulleys are slowing down. that's what the dampner does....dampen the force of the engine 'bang' to equalize throughout the rotation.

[YarisSedan]

Yeah the factory one has a rubber one in the middle.

[severous01]

there's your problem. the nst pulley is not a dampner. it's just a pulley.

the rubber ring flexes on the bang and flexes back on compression. so................................................ .................................................. .................................................. ......

deal is, the pulleys are actually moving forward and backwards at an extreme rate and that's not designed to do it. the dampner stops it and prevents the bearings from slamming forward and back.

[YarisSedan]

Yeah but even a car driven agreesively shouldnt have parts like this failing at such a early stage. Maybe at higher milage i could understand but this is just unacceptable.

My 89 acura legend with 200k miles was a tank. I drove it like i stole it for 4 years and never gave me any problems. Only thing major was the altenator that went out once and i attribute that to my high powered stereo system.

And this a toyota which is supose to be better than honda is having problems like this at such a early stage seems unacceptable to me. So even if i put the factory pulley back on and still drive the car aggresively that means i will be having to change my water pump every single year?!?

I know its a econo car but come on.

[fmicle]

Originally Posted by YarisSedan

Yeah but even a car driven agreesively shouldnt have parts like this failing at such a early stage. Maybe at higher milage i could understand but this is just unacceptable.

My 89 acura legend with 200k miles was a tank. I drove it like i stole it for 4 years and never gave me any problems. Only thing major was the altenator that went out once and i attribute that to my high powered stereo system.

And this a toyota which is supose to be better than honda is having problems like this at such a early stage seems unacceptable to me. So even if i put the factory pulley back on and still drive the car aggresively that means i will be having to change my water pump every single year?!?

I know its a econo car but come on.

I hear you man, I hear you, and I agree it's unacceptable...

[eddy]

just wondering what is this other pulley you are all talking about.?

[JohnnoEH]

Originally Posted by fmicle

I beg to differ. This is a typical mistake people make, just because there is a correlation between A and B it doesn't mean A caused B or vice versa.

There is another parameter C that causes both A and B to go together.

Back to our situation: people with aftermarket pulleys have more water pump failures than the ones driving stock (that's the correlation). So some people incorrectly infer that the pulleys must cause the failure.

Imagine this: people who install aftermarket parts and tune their cars are more likely to drive their cars more aggressively, therefore putting more stress on their parts than those driving stock (grandma, grandpa, uncle Jimmy).

I was going to write pretty much exactly this, but you beat me to it. So many people jump to quick conclusions without looking at the whole picture.

Originally Posted by severous01

does the oem pulley have a rubber ring in it? a dampner?

if it is, then the NST doesnt have a dampner. every time the pulley hits TDC or BDC you're slamming the pulleys on all devices and as the pulley rotates towards bdc or tdc the pulleys are slowing down. that's what the dampner does....dampen the force of the engine 'bang' to equalize throughout the rotation.

Having said the above, this could be the source of the problem; especially when combined with the more likely/frequent hard driving that a modded car will receive.

[thebarber]

undampended pullies eat water pumps....ask anyone w/ a 2zzge..

[rhino5]

Originally Posted by thebarber

undampended pullies eat water pumps....ask anyone w/ a 2zzge..

I find it hard to swallow that the small change in ability to dampen on the crank pulley with a rubber belt driven system could destroy a waterpump so easily. If I was ambitious I'd look up what the flex per foot of our serpentine belt has and I'd be surprised if it was so ridged that it wouldn't absorb some of this "destructive" torque/vibration.

Not saying that is without a doubt the problem, but I'd be leery that it's the new pulley.

[YarisSedan]

Okay so i went out this morning to check the tightness of the belt. When i installed the pulley before i marked the position of the altenator with white out. So the tightness of the belt is the same as the factory installed when i was done. So assume from factory it was isntalled with the correct tightness that would not be the culprit of the original water pump failure.

I have put on about 1k miles since it was repaired previousely after the just put in a new water pump and failed again. This time i look at it the mark i made is still there and it is tighter than what is marked. I did the pinch test and the belt is pretty tight. Not insanely tight but is tighter than it should. So i would attribute the undamped pulley compounded with the overtightend belt causing it to fail much more rapidly this time.

To me that can be the only explination. I have a feeling if the factory pulley was ont he even with a overtightend belt it woudlnt have failed at 1k miles. But more like 50k or later.

I do know overtightend belts cause things such as bearings to faull preamaturely but not at only 1 month after it has been done. Unless superman was doing work on the car and there was no belt deflection at all then even then within amonth still seems kinda fast.

[lilredrocket]

Could it also be that you got a faulty part?

[rhino5]

Originally Posted by lilredrocket

Could it also be that you got a faulty part?

I mentioned this before. Casting metals yields a relatively high chance of poor quality.

[Altitude]

Do you know if your replacement pump was new or refurbished?

[severous01]

is there anything on a EWP? electrics are very reliable, and dont leak nearly as much. and with modern electronix, they last a lot longer. mezerie has one that's boasting 40k hours before it fails. that's like 500k miles unless you're idling all the time. even then if it's tied into the fan relay it'll only come on with the fans.

any way, we got elec power steering, why not water pump?

[lilredrocket]

Garm has an EWP on his setup

[curik]

I'm also looking to get a EWP kit, I posted the details here http://www.yarisworld.com/forums/sho...t=22604&page=2

[ROCKLAND TOYOTA]

LOL at the all the different excuses as to WHY. ive got 18,500 redlined miles on my pulley and OEM water pump which was installed by a toyota tech.

FYI, ive had more than a few STOCK yari come in here needing a water pump and TOYOTA is aware of a problem which is not to say that OVERTIGHTENING isn't a problem either......

[Tamago]

regardless if "improper installation" or the pulley itself caused the failure, the mere fact that you "fixed" something that wasn't broken in the first place (which in itself broke) is the deciding factor.

18 year old kids are most likely to die sooner if they ride motorcycles

but does that mean that the motorcycle is to blame?

no.

see what i'm talkin about?