I have a 1994 toyota pickup 1/2 ton with a 22RE motor.... i recently have replaced the timing chain..... just last week it started to amoke out of the exaust a white smoke only when i started it then it went away and i changed the pvc valve and it does not smoke..... it was loosing coolant last week also but i just drained the coolant out of the new radiator i put in the truck and replaced it today and it seems to be fine.... but is this any sighn of a head gasket leak prob ? if so what should i do?