Ok here is my problem, I have searched on here for hours.. So flame on, I dont care..

I just had the coolant replaced, car didnt blow hot air for a while. Then it ran hot like 220-230degrees for a few times and I immediately shut it off during a test drive. Then the mechanics re drained the coolant and replaced it again. Started to finally blow heat out the heater. Problem is now it takes extremely long to heat up and car cuts fuel over 3000 rpms for some reason!!!! Could a bad thermostat cause the Z to cut fuel?? Ill feel the engine hesitate at about 3200 rpsm and then I let off.. It always does it while in gear, if I sit and rev it up it goes to 4000 rpms with no hesitation.. What could this be? I was told my themo is sticking..

I also have a procharger and run 9psi, and replace the radiator with a PWR radiator... Any help would be appreciated!

 

your original problem is just the fact that these cars are hard to get the coolant totally full when you drain it. especially on the first try. you usually need to drive it abit and keep adding fluid till full. i personally have figured out to park it on a hill or jack the front up and you will get it mostly full the first time.
as far as your current problem, not sure what would be causing a fuel cut (if indeed thats whats happening) with just draining the coolant. a stuck thermostat will not cause this, but would make your car seriously overheat within about 5-10 minutes of driving from cold.

 

They have two valves at the rear of the engine that you may have to bleed the air out. Its a PITA to get the air out

 

Are you talking about the valve with the screw, on the upper left(passenger side of the engine bay) I bled that out... Im so frustrated now, I have spent so much and I cant believe changing the coolant can be such a damn PITA.. It could literally be the end of my car......

 

It feels like a fuel cut or knocking.. I dont believe this is happening.. Its killing my heart!! Thanks for the tip.. Ill bring to Nissan tomorrow and I hope this knocking goes away.. I even reset the ECU twice.. It still knocks or fuel cuts..

 

Were you having trouble before you had the coolant replaced? (ie. heat not working, so you took it in to have the coolant replaced?)

 

I was having troubles like the coolant would burn quick or just evaporate and I would get no heat into the car.. I also think the Z may be experience knocking or fuel cut because the ECU or UTEC senses the bad thermostat..

 

^^^
I don't think the ECU can sense a bad thermostat as some people run without them.

Mine went bad when I put my new engine in and the only thing that happened was it started to overheat but the ECU showed no sign of recognizing the faulty htermostat.

 

just bring it to the dealership... i had the same prob. b4..... from what i remember they had to reset or put the defualt system back on the ecu.... cuz my car used to just shut off when i'd let off the gas while i was driving..... it never ever died on me when i was just reving it or just lettin it sit an idle.... after it came out of the dealership never had the prob again.... but then again that was way b4 i went FI

 

If you were experiencing cooling problems before you brought the vehicle originally in for the coolant replacement, it would seem that it was being lost somehow.

If you are reporting engine knocking, unless you have a leak, it is very possible that you have a very small head gasket leak or very small warped head. In this case, the car would drive relatively normal but when you get into boost it goes through coolant (low coolant creates the air-pockets which get caught in your heater = no heat).

Have you replaced the thermostat?

 

I took it to the Nissan dealership today they said there was a huge air pocket in the system but I will have to check for myself if the problem was fixed because the knocking only occured over 3000 rpms, and I doubt the dealership took it above 3000 for the test drive.. They were prob scared.. I even asked the service manager if he was sure he took it on a good test drive, he called me back and said I was good to go.. I will tell you in a few hours.. I cant believe a damn air pocket in the coolant system would cause so much ****ing pain!!

 

Just got back from the dealer and the car is running good.. It shot up to 210 degrees, that still freaks me out but for now its running.... I wish I could take it to get dynoed again.. oh well... I doubt my thermostat could be bad if my car only had 15000 miles... I just cant figure it out.. I just bought a Nismo Thermostat and I hope it will do the trick.....

 

I think 210 is about normal. I don't have my service manual on this computer so I can't check to make certain.

BTW, if you didn't squeeze the coolant hose at the top of the radiator when you were bleeding it, then you didn't get all of the air out. Trust me, I know.

 

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Did you have this bs problem too? It is so simple yet so complicated and so very important..

 

off my head I thought 190 was normal.....

 

quit using the valet key???

 

What happens if I do use the Valet key?

 

It is typical to see between 183 and 199 degress driving down the road, and 195 to 209deg in traffic / stopped.

We've seen several cases of factory Nissan thermostats sticking.

Hope this helps,

 

It does help, I will have them install the nismo thermostat when I receive it.. I hate the fact they will have to pull the SC though.....

 

Yup.