2003. Been chasing ghosts in the machine. The car will run fine for a bit, then overheat. Race it around town, it's fine. Then hit interstate at 4000 rpms and it over heats. Pull off and race it around and it cools down. Drive it nicely for awhile no issues, race the motor for awhile and it over heats. Drove it for 4-5 hours in the mountains yesterday evening with no issue. Hit the interstate on the way back at mid 4 rpms and it overheated and went into limp mode. I've bled this thing more times than I can count. Gotten all the air out. Tried every listed fix for air in the coolant on this forum, more than once. Both fans work when they should. Can't tell as I'm going down the highway, but when I pull over they are on. Seems to be building up air in the system and then as it builds, it purges all the coolant out through the reservoir. The first time it overheated it split the radiator almost in half. It doesn't seem to want to draw the coolant around as it should. And yes I went to Nissan and bought the OEM thermo. Same issues. Did a pressure test, tightened one hose at the T-stat. No change. I can't replicate it and it just happens at different times. You do something and it drives fine and then , bang. Sometimes after 15 minutes and then after 4 hours.

Ground issue that might bounce and short out the fans, coolant temp sensor on the blink? Micro head gasket leak, but that should manifest after a consistent period of time? Thoughts, comments, criticisms? Spent too much on this so far with no luck. The shop is next, but he basically told me they would do the same thing. Test, try something, see what happens, research, try something, see what happens, etc. They hooked it to the max expensive computer and other than telling us it didn't see the IPDM ( which some guys on here expained) and the bank 2 solenoid was barely reading on the dyno, nothing.

 

If you haven't bled your radiator using a Lisle funnel, you're missing a trick:

https://smile.amazon.com/Lisle-24680...s%2C191&sr=8-3

 

Been there and done that. I've been using it for over a year for various vehicles.

I can get it bled. I know for a fact there is not air in it. I can't figure out how air is getting in or why the water isn't moving and is converting to steam, and then forcing the water out.

It was recently rebuilt, but that doesn't explain the inconsistent overheating.

 

Do you mean the radiator was rebuilt?

 

motor

 

I have an 03 with 230,000 miles on it. No check engine lights. All stock except cold air intake. I went through the same exact problems a month ago. I wish I had a solution for you, but the problem just ended up fixing itself, as sillily as that sounds. I got in one day and it hasn’t overheated again since. I changed the t-stat, coolant lines, flushed the system twice, bled the system countless times, changed plugs, changed temp sensor, and I was almost about to call it quits, thinking it was a weird head gasket issue. Ultimately, I think the t-stat must have been sticking intermittently. That is the ONLY thing that it could come down to after changing that many components. Also, like yours it wasn’t acting like a head gasket issue. So I was trying to rule that out as long as possible. If I were you, I would change the t-stat one more time and go through the coolant burping process again before you take it in. I seriously can’t think of any other issue it could have been other than the t-stat sticking off and on. And we have DAMN NEAR identical symptoms. I hope this helps and I hope you get it resolved.

 

Thanks for the input. I'm going to bypass the T-stat and see what happens. Also looking at the swirl pot. Supposedly eliminates the air. Definitely don't want to crack into the motor again.