So here is the deal, I just recently built this motor, b20 vtec stock sleeves, 11:1 compression, all new parts. After about 1000 miles the engine overheated, twice in a week. I had new hoses and thermo so I suspected it was probably the DX radiator. I went and bought a teg radiator and swapped that in and the problems stopped, cool. 3000 miles comes along, it overheats again. Don't really let it get very high, hit the heater, temps drop and then it's ok. Compression check reads fine. 2 months later 3500 miles overheats again.

The over heating is almost random, it's weird. If I beat on the car, it is fine. If I drive it for long periods it is fine. It seems to act up if I drive the car a lot in a single day and after it has been shut off for a while. Case scenario, last two times it overheated, I did a bit of "spririted driving" at maybe noonish. Run some errands. Car sits for few hours. Drive in traffic for an hour. Car sits. Drive the car home 4 hours later it overheats... I don't quite understand. It's almost as if it gives up at the end of the day but not while i'm pushing it. Any clues?