Not sure what my issue is now....

Runs and drives fine....but after a few min at normal temp, the engine starts to run hot. Then sometimes drops back to normal, then over heats. The gauge is very erratic.

I changed out the thermostat this morning but it didn't seen to make a difference.

I can see a small coolant leak where the top radiator line joins the engine, just past the ECTS unit but it doesnt seem like it would be enough to cause the engine to over heat.

The only other thing I see thats weird is that the tubing between the PCV valve and the metal pipe in connects to flattens out when the engine is running. Like it is sucking as hard as it can. There is vacuum pressure in the line past the PCV valve so that may be normal, but I never noticed it before.

Any help or ideas would be appreciated cause I am stuck.

 

Sounds like 2 different issues. The pcv valve maybe stuck closed. It should be allowing air to pass when in idle. If the car idles for 5-8 minutes do the cooling fans come on? If not then you can go from there. If you changed the thermostat the system may have an air bubble in it.

 

I've noticed that maxima are very sensitive to air in their cooling system and they are tricky to bleed.
I've done that recently after replacing my radiator.
CAUTION: Don't burn yourself while removing radiator cap as coolant can be hot when car is warm!
Top up the radiator (and expansion bottle to min or little bit more), drive the car till it warms up. Don't forget to turn the heating to max and if you have AC, turn that on as well. I've did that all without radiator cap on.
Park the car so that front end is higher (i've used kerb on one parking), go under the hood an rev engine (2500-3000 rpm) so that water pump circulate little bit more (you will see coolant fluid "flowing" and if there is air in system you will see bubbles popping up). Add coolant as it drops how that air bubbles comes out. After 5 min or more, top up to the radiator, return cap on and go home. after the car cools down, top up radiator more if needed and that should be it. next time you drive the car, check the expansion bottle level when car is warm, add if you need (i didn't have to as I have topped up my radiator when it was cold). I have also repeated that after few days just to be sure that it is bleed properly.
I hope that if you have just air in system this will help (and that it was more or less clear considering my english knowledge).
If that don't help you, maybe you've installed valve wrong or that valve doesn't work either (seen on few forums that that is very common).
Cheers mate.

 

If I follow the above post correctly, he suggests driving with the radiator cap off....I personally would not do this, and in fact, it is not necessary to even move the vehicle. See this link HERE and follow this. This is how I did mine and it worked perfectly!!

 

No, it's not necessary to do that like I did, but I couldn't do it properly like it's described there.
I drove a car to heat it up faster and to move from my neighbours and to find decent kirb to put front wheels on it. Also drove it without cap to get some air out while driving on higher revs (it's not the same if it's idling and when you rev it - pump pumps higher and more bubbles comes out).
Point is to get the front end as higher it's possible, to rev engine and hold it like that for a while and to top up radiator at the end.

Good luck anyway, how ever he tries!

 

Even a very small hole can cause problems. I was having issues with my engine over heating & the coolant level was fine. I ended up getting the cooling system checked & the radiator had a very small hole. I replaced the radiator, & the car was fine after that. Might be worth getting it checked out.