i keep having to refill my radiator about every week or so, but the odd part is that the reserve tank stays full. i cant seem to spot any visible coolant leaks. here's some info on my car:

-95 civic ex coupe
-203,000 miles
-original block
-head was replaced about 5 years ago due to a blown head gasket and subsequent overheating which caused it to crack
-water pump was replaced last year
-distributor was replaced about 4 months ago (i don't know how relevant this can be)
-rear main seal is leaking (again, i don't know how relevant this can be)
-if it happens to be a cold morning, the first start up produces a very rough idle that lasts about 10 seconds (im thinking this is more of a fast idle valve or sensor problem though)

could i have a blown head gasket again? i don't see any coolant in my oil and im not blowing any white smoke. but the again, i didn't notice this either the first time it blew.

the car runs great otherwise. what do you guys think?

 

do a pressure test on your coolant system and most likely you have a very small leak.

 

Refill it once a week?

Thats more than a small leak. I'd check my oil make sure the headgasket is still good and your not burning coolant or got a cracked block and its leaking into oil ( Which would cause your main seal to leak as well )

 

i checked the oil and it doesnt look like there are any traces of coolant on the dip stick or filler cap. however when i opened the radiator cap i heard a hiss, so now im suspecting its the head gasket. would a cracked block also force air into the cooling system?

 

You could do a block test ,that will show if you have combustion gasses in the cooling system.

 

Mine did that and was leaking out of my heater core. Keep your a/c and heat off all week and see if you don't lose any. There is a small tube coming out of the firewall, when I ran my heater I could see water coming out of it, I think it is some sort of emergency drain so you don't get the carpet all wet.

 

Open your radiator cap with heater off and ac off.

When t-stat is closed, check for bubbles coming up.

When t-stat is open check for bubbles ( Dont mistake this for coolant flow )

let me know what you see.


Quick check for a blown headgasket is pull your oil cap off, go to come clean cardboard fling the residue on the cardboard, if its only oil then your good, if its mostly coolant than the headgasket is blown. If its a minor amount then your head gasket is leaking which isnt where the coolant is going.