Hi my name is Milton and I own a 2004 Toyota Camry 2.4. I bought the car 8 months ago and now It has 129 K miles.

The reason I’m writing is because for the last 3 months I’ve been hearing a slowish noise inside dashboard is like air on the cooling system.

I started checking the coolant level inside the radiator when cool and I notice level is always down and the reservoir full… the liquid expands when hot but is not returning to the radiator when cold.

The car is not overheating at all, never.

2 weeks ago I performed a general maintenance of the cooling system:

• Coolant flush and replace (Toyota pink 50/50)
• New thermostat from dealer (82C)
• New temperature sensor /switch from dealer
• New inlet and outlet radiator hoses and clamps
• New cap from dealer (108 kPa)
• Air bleeding
• Scangauge installation for real time temperature check

Saying that I admit the temperature is almost 4 degrees cooler than before. Now on cruise speeds on highway is between 186 and 190F.

But the air bleeding just last one day or two. I can hear the air flowing with liquid on the heater core.

Then I also perform a Combustion gases on coolant system test… 3 times… no color change on reactive liquid… always deep blue.

Checked spark plugs and all looked good,  no liquid on them.

The car runs perfect, no delay starts, no misfire, no smoke on exhaust, no excessive fuel consumption, good acceleration….

I’ve read that 2AZ-FE engines have problems with the head cam bolt threads but I would like to confirm if I have a blown head gasket.

Nowadays Time Sert kit is really expensive not including the other parts needed for the best results.

I was thinking of perform a cooling system pressure test and a borescope cylinder inspection. Not sure if my bleeding is not correct.

Any professional and reasonable comments will be appreciated.

Thanks for read.