[shivparekh]

Thanks for your help with this issue.

I have 2.0 I4 engine with auto transmission.

If you mean cold air thru cabin vents, that seems normal without any issue. I had a mechanic do the diagnoses, and the water pump is fine, also the coolant pressure check turned out to be ok. Also, time to time i have looked at the oil dip stick , and haven't found any sign of coolant mixing with oil.

Midas did the same diagnoses, and they found coolant under the engine body, and determined that there's a blown / damaged head gasket. but the previous (local) mechanic told me that i can live without changing the head gasket as long as i maintain the oil level to certain point.

When ever the car heats up to more than half on the gauge, the revs would start going crazy as if you are driving at high speed in lower gears and at the same time, i felt gears start changing randomly.

I also read somewhere in this forum that this is a problem many or atleast few have experienced with ford transmissions of early built. and some suggest, to let the engine cool down and then you can drive again with no problem until it heats up again.

I have read many threads / thread replies from you, i feel like my case is in good hands now.

Thanks again.