I just recently replaced my engine with a brand new remanufactured engine...I've put about 600 miles on it...
Runs awesome, but now I've run into a overheating problem, first thoughts was thermostat & rad cap so I replaced those & i'm still having the same issue.
After about half a mile of driving the temp starts going up, it's pushing coolant into the overflow tank & overflowing if it gets too hot. Once you let it cool, it all goes back into the radiator leaving my overflow tank at MIN
My radiator fans are working, so could it only be a waterpump?
Really frustrating spending $4,000 on a new motor & I'm running into other issues...
The place I took it to, all they work on is 350z,g35, & vq35 engines so I'm sure they knew what they were doing, I don't think it has anything to do with them putting on something wrong...
What could it be?

 

Do you own an obd2 tool or one of the wifi devices that connect to your smartphone?

Easy answer, check for air in coolant system.

Hard answer,

Watch a few of the engine parameters like coolant temp, flow rate, etc. Sounds like you are going to have to find it yourself.

 

Yes my next bet is to bleed the cooling system... The rad fans are working, not the thermostat, & they said my car has a new waterpump so I guess I can rule those out... Has to be some kind of air pocket

 

Hey @Freshhkiicks by any chance did u ever figure out the issue? I’m having the exact same problem with my G and I’ve been at a total loss after bleeding it like crazy, new thermostat new hoses new radiator

 

did you get a new engine too?

 

Lots of hoses were reattached and probably in a hurry.
Expect to find a loose or not so springy hose spring clamp somewhere.

The hoses going into the TB can be a hard place to check.