I have bubbles in the coolant overflow tank when the car is at normal operating temp. When the engine is cold there are no bubbles, only when operating temp and especially after I drive it. I thought a blown head gasket would leak all the time, hot or cold. whats up.

SOURCE: Determining if head gasket is blown on a 1994 honda accord Ex w VTec

White smoke out of the exhaust is one indication that the head gasket is blown. Another is to start the car and check the oil on the dipstick. If it's frothy or looks like a milkshake, this is another indication of a blown head gasket. The milky appearance indicates that coolant is in your engine, caused by a bad head gasket. If none of these symptoms occur, then the problem lies elsewhere. Hope this answers your question and feel free to post back with any other concerns or questions. Thank you.
Greg

SOURCE: 04 civic heater blows cold air at idle

you should have hot water on all rad. hoses when the motor is running at a norm. temp. the water is not going through the heater core like it should. you have cutoff valve bad low water are a stopped heater.try a hoter thermostat if none of the above are true.

SOURCE: had antifreeze leak now car wont start

ur vehicle overheated.. ur timing belt and or water pump may be broken and or worn..take the vehicle to a reputable repair shop or dealership

SOURCE: 2005 honda civic radiator fills the overflow

Always remember and I "Stress" although its "New" don't mean it comes without "Defects"

However if fluid is going into the reserve tank it would indicate a need to replace the cap although sounds as if all the bases were covered along the way , but could be a faulty thermostat , and you from time to time watch the temperature gauge and its normal level correct ?

i would after a good few hours or even overnight allow the vehicle to cool and then 1st thing open the hood and remove the radiator cap , ensure the radiator is full and leaving the cap off put a piece of cardboard under the vehicle this will allow you to see if coolant is leaking anyplace else ...start the vehicle and after a few minutes it should begin to exchange and you will notice the exchange of fluid replace the cap unless it drops considerably then add fluid so keep it open and nearby , reconnect the cap and always watch out for moving parts and "Never " wear loose articles of clothing and keep you hands etc away from moving parts ..{just a reminder} and note as to when the fan"s engage .at this point look at your temperature readout is it normal range ...watch the reserve for fluid filling it
up .
as well look under the vehicle and watch for any leaks onto the cardboard !

if all else fails at this point take it to a parts store that will have a code reader ...it simply plugs into your vehicle and without starting it turn the key to the on position and allow it to communicate with your vehicle any codes or faults will appear and should be wrote down any and all of them ...they may tell you exactly what the codes read and if applicable you can purchase any parts needed at that point ..

however to me i am leaning towards improper fluid temperature settings and as well a faulty "Thermostat"..turn on all your heat switches and fan to full with the engine running are both hoses going into the heater core going into the firewall hot / if the top is hot and the bottom is cold then it suggests the heater-core is plugged and requires a flush if both are hot then the water pump is working "

if you have a bery high abnormal reading on the temperature gage and everything is normal otherwise it could be a faulty temperature plug

ensure any and all wires are not touching the engine block causing the Gage to ground out giving a false reading

but this is where i would begin hope it helps you somewhat

SOURCE: When turn on the car in the morning, i accelerate

To begin with, if you are revving a cold engine to 6000 RPM, you are asking for a blown engine. Most OBD vehicles are equipped with a rev limiter that will cut off fuel at 3000 to 4000 rpm to prevent you from over-revving your engine and blowing it up. If yours is revving to 6000 RPM cold, then the rev limiter, for some reason is not working while it is cold. I have no explaination for this. The best thing I can tell you is to stop revving your engine so high when it is cold unless you really want to see what an engine looks like after is has gone off like a grenade.