on a hot sunny day, stuck in traffic, the temperature goes up to about 3/4ths way for about 5 minutes, before the traffic cleared up and temperature returned to normal.

after competing the drive, I checked the engine bay, and noticed a coolant "splash" mark on the left side of the engine/distributor (first picture)


after another 3 hour drive, I checked the engine bay again, and found more coolant has sprayed onto the engine, coming from maybe the upper radiator hose?


the coolant levels have dropped a bit in the radiator. on top of that, there is this "gurgling" noise coming from the thermostat housing.

further notes about the car: d16y7 - the upper radiator hose is new as I replaced it when I did the head gasket last summer. the thermostat was replaced about a year and a half ago.
my thoughts is the upper radiator hose clamp is not tightened enough from when I replaced it, and some pressure escaped when the hose expanded from the hot summer day! but I would like to hear other thoughts on where the coolant could be coming from

Thanks for reading 😊

 

My guess would be the heater hose. This hose usually deteriorate faster if oil leaks from the distributor on to it.

 

I love your answer because during the winter, I had problems with my heat turning cold whenever nightfall came. I think it could be the heater hose allowing cold air to cool the coolant down before reaching my heater core. Does that sound right to you?

I will also investigate the heater hose tomorrow to notice any cracks.

Thanks for your response! 😊