OK.... so this all started a week ago. Car keeps over heating and I have replaced everything except the radiator. I have burped the system sooo many times now its ridiculous. No leaks in hoses, and everything is tight. Replaced thermostat. Like I said it happens all the time. Its like sometimes the thermostat wants to open and then other times it just says F*ck you. Like tonight, It was overheating on me on the way home. Got home and upper hose was hot as hell, but the lower one was cool to the touch. SOOO what would make the thermostat not open??? Is there a sensor I need to replace or somthing? Thanks guys.

 

What consists of everything?
Sure the thermostat just isn't a dud?

 

Im pretty sure the thermostat isnt a dud. Before I replace the thermostat I took the old one out and put it in hot water and watched it open. So I knew it probably wasn't the thermostat but I changed it anyways.

I guess I didn't replace literally everything. Replaced hoses, thermostat, flushed the system, bleed the system. I figured that these are the easiest things to fix and most of the time the problem. Either air is getting in the system some how which is causing the air bubble which in turn causes the thermostat to not open, or something else is faulty.

 

Just throwing out some ideas.
Are the fans working properly?
Coolant Mix?
Water Wetter yet?
High Pressure rad cap?

 

Well.... The fans are BLASTING now cause the car is overheating, because the thermostat isn't opening. lol.

Coolant mix is 50/50 (shouldnt matter anyways, water cools better)

Water Wetter wouldnt fix this. Its spiking the gauge.

13lb OEM replacment cap.

 

Sorry, I don't know GL

 

hahahah... I don't either man.

 

What about the new themostat? I'm sure you did, but just want to doublecheck.

 

is coolant flowing? blockage of some sort? is there a coolant pump? I guess you've already checked all the possible causes in the service manual under "engine overheats" troubleshooting?

I think you can monitor the thermostat on/off using the nissan CONSULT tool or Cypher from uprev (although i'm not positive on this). You might even be able to control it.

 

maybe water pump,bad pump =no circulation no matter how good your stat is!

 

Possible failure modes for a car to suddenly begin overheating (not necessarily what may be causing your problem)
1.Insufficient coolant
2.A leak (maybe headgasket) smoke at exhaust?
3.Bad T'stat (partially opening or not at all)
4.Air in the system( back pressure)
5.A blockage somewhere
6.Bad water pump
7.What else??

 

It does sound odd. You really cannot monitor the thermostat as it is a mechanical action not electrical, but having changed it I doubt it is bad.

As for a bad water pump the only thing would be if it fell apart which could cause a blockage plus no flow, you can check the water pump by removing it, to get to it remove the lower right side cover and then the pump, you will have to drain the engine.

 

i've seen impellers dissolve from bad grounding on car putting a charge into coolant.i think you meant left (driver) side of engine,right lower is tensioner.

 

Well I was referring as if I was looking at the engine, which is what people do normally, but yes drivers side.

Onanother note, I saw on another forum where the driver had to change the radiator, so not sure if like window motors the radiators on our Z's have a short life

 

left and right should be described from the driver seat ,that is the standard ,from looking under the hood or side of car or from top just adds confusion and is the reason people get lost around the car when looking for something.sorry to get all picky but if everybody did it the same people would have a much easier time.

 

So is the water pump hard to replace?

 

It would be easy with the engine out, the main thing is getting a good look at and access to the bolts holding the water pump in place and you have to remove the tension on the chain. So it is not hard just pretty involved.

REMOVAL
1. Remove undercover using power tools.
2. Remove drive belts. Refer to EM-14, "Removal and Installation"
3. Drain engine coolant from radiator. Refer to CO-8, "Changing Engine Coolant" .
CAUTION:
Perform when the engine is cold.
4. Remove water drain plug on water pump side of cylinder block.
5. Remove chain tensioner cover and water pump cover.
6. Remove the chain tensioner assembly with the following procedure.
a. Pull the lever down and release the plunger stopper tab.

Plunger stopper tab can be pushed up to release (coaxial structure with lever).
b. Insert the stopper pin into the tensioner body hole to hold the lever and keep the stopper tab released.
NOTE:
An allen wrench [2.5 mm (0.098 in)] is used for a stopper pin as an example.
c. Insert the plunger into the tensioner body by pressing the timing chain slack guide.
d. Keep the slack guide pressed and hold the plunger in by pushing the stopper pin deeper through the lever and into the tensioner body hole.
e. Turn crankshaft pulley approximately 20° clockwise so that the timing chain on the chain tensioner side is loose.
7. Remove chain tensioner.
CAUTION:
Be careful not to drop mounting bolts inside chain case.
8. Remove the 3 water pump fixing bolts. Secure a gap between water pump gear and timing chain, by turning crankshaft pulley counterclockwise until timing chain looseness on water pump sprocket becomes maximum.
9. Screw M8 bolts [pitch: 1.25 mm (0.049 in) length: approx. 50 mm (1.97 in)] into water pumps upper and lower mounting-bolt holes until they reach timing chain case. Then, alternately tighten each bolt for a half turn, and pull out water pump.

Pull straight out while preventing vane from contacting socket in installation area.

Remove water pump without causing sprocket to contact timing chain.
10. Remove M8 bolts and O-rings from water pump.

 

Damn..... I sure hope its not this sh*t. Im too lazy to do all that. It might be dealer time......

 

coolant mix wont matter
watter wetter is GARBAGE
a high pressure cap won't help

I hate to be the bearer of bad news, but either you've got some serious blockage in your system (flush it out completely) or, a serious headgasket issue, or you've still got an air pocket. Lots of twists and turns in the path the coolant flows and even a small bubble will wreak havoc. I know, I had the exact same issue when we put my new motor together and it took literally 5 days of burping the system multiple times per day to fix it

If your rad hoses are getting firm, you either have an air pocket, or a headgasket problem. Another hint - if your upper rad hose is hot, and your lower is cold, you've got air pockets - exactly the scenario that happened to mine

The water pump really can't go bad...its driven by the timing chain. Either its spinning (which it is if the car starts) or its not (which means your motor is seized). If no coolant is being lost (ie leaking out of the front cover in the motor), your water pump is fine

 

OK cool thanks. Is there any like temp sensors that can go bad?