Okay I've been fighting with my 2000 X for months now.
I took it into my Nissan dealer and had them run a full diagnosis on it. It came back that my radiator and lower hose needed to be replaced, costing about $850.
I did some research on here and looked at how difficult it would be to do the work myself. Found all the parts online, and replaced the radiator, upper and lower hose, all of the hose clamps, the thermostat and the temperature sensor.
I figured it would be easier to replace anything that could have gone bad with the couple overheatings I had encountered.
Put all new coolant in, and bled the system multiple times in order to ensure that I do not have any air left in my system.
I drove to our lakehouse this past weekend, and stayed at a normal temp until exiting off the highway when my car overheated.
I drove on the highway for about an hour, going between 55 and 75 mph.
We thought there might have been air in the system still, so I went through the bleeding process again. Same thing happened on my way home from the lake.
I can drive all around the cities going 60 mph to and from class with no issues. It only happened after driving on the freeway for an extended period of time. I asked Nissan to specifically check my head gasket, they said they tested the pressure and it was fine.
I also am leaking a small amount of coolant still, while all of my hose connections are dry. So I have kinda limited it down to the fan clutch or the water pump, but I am not exactly well versed on cars or know much of what I am talking about except for the research I have done.
Does anyone else have any ideas? Everyone I have talked to isn't really sure of what is wrong. I appreciate any help that I can get. Thanks so much!
This is a really confusing somewhat contradictory series of descriptions.
I'll take a stab at at least trying to help summarize your plight:
1) You were over heating, but under unknown conditions. ("A fight"?)
2) The dealer said you needed a new radiator and lower hose.
3) You decided to instead do a radiator, hoses, thermostat and temp sensor, figuring the shotgun approach was in order.
4) Its still over heating...but, at low speeds (pulling off the road), possibly on the highway, possibly not, as you are a bit vague about what was happening...both seeming to say it was fine (To class and back at 60 mph), and also seeming to think there was in air the system at the same time...so, I'm not sure why, unless you were over heating? So, its over heating on the hwy, and, at lower speeds too?
5) You're missing a little coolant, but don't know where its going.
Please correct/fill in missing details for the above as appropriate.
Next steps that might end up being a good idea:
1) Do an OBD port reading in real time when the dash gauge says you're over heating. The dash gauge is wonky, and, most wonky after the thermostat is changed or it is messed with....reading high, on an intermittent basis (Which you report). The OBD/ECU uses a SECOND temp sensor that is in a different location, and, which is more reliable, and which gives the readout in degrees.
If during over heating, the OBD says its NOT too hot, then, the sensor by the thermostat is wonky, and, you're not actually over heating.
2) If the fan clutch is the issue, its not typically an issue at high speed, as the wind through the grill is providing more CFM for cooling than the fan could anyway. If off road, in slow traffic, etc, is when it over heats (Instead), then the clutch is more suspect. You can test the fan clutch to see if its working.
3) I didn't notice how many miles you had on it. If over 105k, it was due for a timing belt change, and, most people do the water pump when they do the timing belt....as they have to open it all up anyway, etc....so, depending on the maintenance history/mileage, you may need a water pump.
4) If the radiator cap is a wee bit loose/leaks air, you loose pressure, which allows the coolant to boil/suffer cavitation, and that can both cause a small loss in coolant, as well as more over heating.
5) If the heater core or the hoses to that are leaking, you can lose coolant, and pressure, as well, leading to an analogous problem.
6) I don't know you, so, just in case, when you add anti-freeze, you reduce your ability to cool. IE: Pure water cools better than water and anti-freeze. So, too much anti-freeze makes it over heat more easily. 50/50 is typically considered an OK ratio...more than that is worse (As far as cooling goes). Lubrication and not FREEZING are another story.
7) Merely over heating can cause a spike in pressure and release of steam, and, that steam equals a loss in coolant all by itself. IE: You don't NEED a leak to lose a small amount of coolant if you are over heating.
8) Look in the engine oil for emulsions (Creamy stuff) and in your radiator coolant for a rainbow sheen (oil)...to see if the two are trading fluids, as a back up.
Run through the above, and see what makes sense.