so i recently upgraded my stock radiator to a 3 core all metal one.
now a week later i notice that any time the heat or the air is on i'm leaking coolant from the radiator cap. i thought well its just the cap, picked up a new one, same problem. almost like the cap isn't seating correctly or something. any clue????? also, why would it only do it when the heat or the air is running???

one more just for fun.......my electric fan is coming on for like 2 seconds and then going off.......on for two seconds and off..........any clue???

thanks guys

fan running every couples seconds, does your a/c compressor clutch kick in and out at the same time? the comp. will cycle when: you have selected defrost or a/c. but cycling that quick means, low charge in the system. [freon or R/12]. turn the air flow to the floor, does the fan stop?

as for the cap, aaahhh, poor seal, can you go back to were you got the rad. and get a matching cap? maybe,maybe aftermarket caps are slightly different? hope this helps.