Instead of starting a whole new thread I thought I'd just update this one.
Once again, summer is here and my car is running hot to the point of nearly overheating. Though I can't say I've actually overheated because I've never let it get that hot, and the coolant is not boiling in the overflow tank when car is running hot (nearly outside the "normal operating range" on the factory gauge)
To recap what I've replaced and installed over the last year:
Nissan OEM thermostat
Upper and lower hoses
Found a bad clamp and replaced several clamps
Leaky freeze plugs(put in rubber ones to hold until I get my SR, and yes they are holding)
Cardboard upper cooling panel lol
Altima dual fans and DFI controller, no more clutch fan
Now the symptoms:
I've pressure tested the system, and it will hold 21.5 psi for 30 mins, but at 23psi(testing pressure) it will slowly leak down to 21.5 and hold.
Car doesn't visibly leak coolant, although it does leak oil from somewhere, and now seems to heat up somewhat slower than last summer. I can drive around for about 20 mins before the factory temperature gauge starts to rise above the halfway mark, and it will get up to the top of the "normal operating range" of the gauge if I drive for extended periods. Of course, the entire time I'm using A/C except when I think the engine will overheat. As a side note, ambient temperatures here in Vegas are around 100*-110*F.
Fans are coming on and even go into "cooldown" mode when running hot.
I also installed an electric Sunpro water temperature gauge and upper radiator hose adaptor to monitor water temps coming out of the engine. I don't know if this is good but as I was driving around tonight the Sunpro gauge was reading 190-200*F and the factory gauge was sitting just under the halfway point, ambient temperature was ~95*F, and I wasn't using A/C, that seems high or an incorrect temperature reading.
Sorry to make that a long read but again wanted to bring everyone up to speed with what I've done to remedy this problem, so to ask my 2 questions now:
1. 190-200*F seems to be a high operating temperature, especially since I wasn't using A/C. Is the Sunpro gauge off, or possibly my grounds are bad? I grounded the gauge inside the car and even grounded the hose adaptor. On both grounds, I sanded down to bare metal to ensure good connection. The gauge has a mechanical face and the sender is electric, if that helps.
2. Why is my car still running hot? Again, I never let the car actually overheat, and if I turn the A/C off the engine temperature actually does start to go down. Yes the factory gauge has been acting funny(as I've read these gauges do), hence why I got the Sunpro, but It does seem correct as it's not completely erratic, just somewhat bouncy when hard braking or cornering.
I've bled the car many times, taking about 15mins each time to "ensure" a proper bleed, yet the car still runs hot.
I'm going to monitor the temps on my Sunpro gauge and compare to the factory gauge over the next day or two and update what temps the Sunpro gauge is reading, though again, the Sunpro gauge seems to be reading a bit high at 190*F running temperature...
Any help with these questions would be great and hopefully will buy me some time until I can get my SR
Thanks again folks! You are always helpful.