ka24e weird water pump problems

[Frankenfourty]

Ok, so I have a weird water pump failure issue that I really cannot figure out. The car is an 89' s13 KA24E. Here's whats going on, I bought the car knowing the water pump was bad so I replaced the water pump with a brand new unit, and while I was at it I replaced the thermostat. I put everything back together and everything was fine when I started the car and checked for leaks. I then drove the car home and it was at operating temp with no overheating issues, I parked the car and checked it after about 2 hrs and it was still not leaking. Then I checked it in the morning and there was a big puddle under the car. I then started the car to take it back to the shop I use to work on my cars and by the time I got there the car stopped leaking. So I let it sit to cool down, and after about 1.5hrs it started leaking again....heavily. I have confirmed that it is leaking out of the weep hole on the water pump but I do not know what would cause my brand new pump to fail. The only thing I can think of is too much pressure. And I did figure out that I installed the thermostat upside down where the air bleeder is supposed to be upwards, I installed it downwards...... don't know if that would do anything. What would cause my brand new pump to fail? I need to figure this out before I throw another pump on and trash yet another one. And just to help in the diagnostic process, I did do the service properly. Any help will be greatly appreciated. And yes I did also post in the Nissan Online Mechanic, I posted here also because I need to figure out this problem ASAP.
Modified by brian's13'240 at 8:43 PM 7/26/2009

[gpelite]

BUMP

I need a similar answer here. Just did the radiator on a KA24e and the thermostat. I thought the thermostat seal was bad so I tore it down again and resealed it with a new gasket and sealer! It seems that the backpressure when sitting after I turn the key off it instantly sprays steady until the pressure is out of the system (leaving almost no coolant). I thought it was the thermostat seal, but after painstakingly redoing it all, I don't see how it is possible.

System runs FINE cold and IN DRIVING, once the key is off. It leaks steady until it is pressurized with the outside air. Are there common fail points in the coolant hoses around the thermostat housing? TB lines leaking?

Can someone explain the pressure of the system when the key is off and the water pump is not moving so I can narrow this? I thought it was blow by. How do I check this if I am running too much pressure in the radiator cap? What is the stock PSI for the coolant system cap, I know my aftermarket PSI but not the OEM pressure. NEED THIS #

It is important to note I did all this due to overheating, and it worked fine for about 2 weeks with new equipment. It is also important to note I NEVER had leaking here before my upgrades, only in the rad. which prompted the upgrades.

Not trying to hijack the thread, but I think it might be along the same lines.

[Cone Junky]

Unfortunately you probably got a bad "new" part. If it's leaking from the weep hole, I really don't thnk you could take any blame for it's failure. Time for a warranty.

As for the other post, you'll need to pressure test the system when it is cold. The only way we could diagnose a coolant leak is to physically see it.

[Frankenfourty]

Thanks cone junky, I was really hoping that I just got a defective pump. I just wanted to make sure so I didnt throw a new one on and ruin another. Thanks for the help.

[Vegascorbin]

I also vote bad part. The key to me is that the system pressure is going to be highest right after you turn the car off. If the leak was due to pressure it would habben then not 1.5 hours later when the pressure has bleed off.

[Cone Junky]

There is a chance you totally overtightened the belt and wiped out the bearing, but I still think you just got a junk part.

[Frankenfourty]

Well I think last time I adjusted the belt correctly with 6-7mm of deflection. I just put the new pump on and I guess ill see what happens. I let you guys know what I find out.

[Frankenfourty]

Ok, well I took the old pump off and the seal for the bearings was improperly pressed in from the factory. I have a new pump in and looking forward to driving this thing. Thanks for the help everyone.