Ok I would overheat randomly I replaced the radiator hoses thermostat and still my overheated so then I replaced the waterpump the old one looked good and I replaced anyways now sometimes the thermostat still doesn't open and ill overheat randomly and when it starts getting to heat water leaks from weeping hole what could be wrong?

 

water pump?

how many miles on z? waterpumps on nissans suck

 

Make sure both fans run. Test by turning on the air conditioner.

 

Brand new water pump and fans both work ill bleed the air out as best as I can and run heater everything will be fine then after a few drives it will start getting hot the top hose will be hot bottom hose cold and ill be leaking from the weeping hole so ill bleed system again and then same problem a few drives later I replaced the pump after thermostat was replaced and had the same problem I've ran without a thermostat and it will be fine and I've boiled two thermostats and they were functioning properly as far as I can tell maybe air in the system that's stuck would the pressure from getting to hot cause the weeping hole to leak?

 

What could cause the car to heat up and thermostat sticking

 

how are your fluid levels when the car is cold? is level on you reservoir tank constant or does it change sometimes. My suggestion is to fill it to max hot after you engine is warmed up and check again the next morning when cold to see if any was sucked back in. You wont be able to bleed it properly if you keep driving it around. Let it self bleed.

 

The reservoir is staying pretty much the same I have a radiator cap that allows me to relieve. pressure if that can help at all. Would the air in the system that's causing the tstat to stay closed and building the pressure cause it to be leaking from the weeping hole in the water pump?

 

So I jacked up the front driver side and spent about an hour bleeding the system. Everything seems to be working perfect. I took your advice after finishing I put coolant in the reservoir to the max hot I'll check it in the morning. I will also jack it up and see if I can find anymore air bubbles then I'll drive it around town running errands to see if it has any same problems like leaking from the weeping hole although im sure it is fixed. I also just put in a stage 1 Exedy clutch it hasn't ever been so responsive.

 

Ow, yeah???

How does it suck????

No plastic wheel paddles, driven by the chain, what possibly could be wrong with it???

There is no way it goes bad unless you put a bunch of stones inside radiator and let the car run for a while.

To bleed the system completely you need to:
Fill up radiator and plastic reservoir completely.
Turn on the engine and the heater full power!
Wait for the temperature to go up.
When it starting to go up turn the engine off and release this air relief plug



then close it and repeat the procedure several times!

 

How does it suck?

Let's see, I've owned about half a dozen nissans, some brand new some not so brand new, all water pumps went around the 50 to 60 thousand mark, without fail. I remember I had a brand new 02 spec v and around 45k miles the waterpump failed. I changed my thermo on my z and swapped my water pump at 60k miles and guess what the water pump was on its way out...might just be where I live and those types of factors but I've only known nissan waterpumps to die around that many miles....

I have a lexus on the other hand, just broke 100k and doesn't need it.

 

I'm not talking about the rest of the nissans out there. I have a water pump from VQ35DE right in front of me! And I do not see how in this world this thing can break up... Everything made of metal... Straight chain drive without any other adapters or connectors... What do you mean by saying on its way out?? Which part of it went bad?

 

How can you see a weeping hole in the water pump?

 

Have you considered it might be your headgasket?

 

The pump is supposed to function with very little resistance. A brand new pump will be able to spin in your hands fairly easily. A seized pump will give resistance/feedback - this may seem small but I've seen the difference it makes first hand with temps.

 

Between the two O-rings on the pump there is a hole, this is the weeping hole. So that the oil doesn't get in the coolant and the coolant in the oil anything that gets past o-rings will drip out of this hole on to the ground on the drivers side. So I drove it about 30 miles with the heater on full blast it ran perfect and had no signs of getting hot. However, I grabbed the bottom hose and it was slightly warm more so cold as if the tstat never opened. I highly doubt I have a head gasket issue, no white smoke, when it does get hot the bottom hose is cold, and if there is any coolant loss I can see it is dripping from the drivers side where the weeping hole would be. For now everything seems to be fine I just wonder till how long seeing that this is recurring. I am going to bleed the system yet again to make sure no air is hiding in there. Possibly do you think the tstats have been ****? They are duralast I boiled them and they opened though. When I run without a tstat I have zero problems.

 

Glad to see everything is working out better,, but if you can, get an oem t stat. i never trusted the duralast stuff.. plus you said you boiled them and they opened, at what temp? at 212F boiling point its kinda too late. they should open between 150 to 170F?

 

Might be your radiator cap not holding pressure properly. Try your stock one and see.

 

I am getting an oem t-stat from Nissan Monday ill get another cap too I was doing some more driving to test it and it does seem to open a lil too late and yes when it was boiling they would open around 212 so im thinking they are garbage and the cap seems to not relieve pressure it will have air trapped and not take any coolant from the reservoir.

 

Thank you kind sir. Even though your post is almost 2 years old it was exactly what i needed to probably bleed out the air in the coolant system. Even after i changed out the thermostat the car still over heated. Did a quick search, saw this post, ran out side and did exactly as you said. Now the needle doesn't even go past 40%. Again, thank you.