Take the 2-minute tour ×   It has been a year and a half and it
is now happening again! (same exact presentation.) It started
happening again when it started getting cold out and is still
going on now. Took it to the mechanic that swapped out the
radiator and he's stumped.  No leaks, but couldn't the head
gasket be leaking on the inside? How would I know if the head
gasket needs replacing?  Been noticing lately that my heater
stopped working and temp climbs to red. Came to find out that I
had no coolant in engine.  Filled it up. Problem is that it
still happens.  Now, radiator full, Heater works fine, but if I
drive it for a while, temp climbs and heater stops working. Took
it in. Mechanic said coolant pump was leaking. replaced it, and
temp sensor.  still happens!  Here is how I can reproduce
problem: Drive with high RPMs for about 15-20 minutes. I put it
in Low 3, and got on the highway for about 10 minutes. This kept
the RPM gauge up to about 4 or 5. temp gauge climbs rapidly once
it decides to start.  I d