So I’m re-writing this as to not completely deter people lol… Scroll down for more details…
Recently had a new water pump and radiator put in my car. Not so sure if they are “new” but anyway.
The car does not seem to use coolant it has only slowly flowed back into the reserve tank over time spilling over a little.
Read my next comment and look at the photos if you will please.
Thanks friends!
Block tests miss pinhole leaks in head gaskets all the time.
I honestly am having difficulty reading this post and sorting the info in my head…
Here is what I have taken home from the above post. Wait sorry…I just read it a 3rd time…and My Brain hurts.
A 97 Civic has a T belt driven Water pump… NO? Yes it does… OK…so you basically had an overheating Civic… It finally killed the water pump prompting a total T belt job including water pump
Now you have puking up coolant in the res…Wait no…you dont…you did that… . You are concerned you have a bad head gasket
HOLD ON…Here is what you do… Fill the rad and the Res… BURP THE system using the bleed nipple near the thermostat. Be sure you evacuate all air from system…have the heat setting on HOT in the car while burping the system
Get vehicle up to temp by normal operation… After about 20-30 min of normal driving feel the Rad Hoses… Are they Hard? Do you hear bubbles and gas escaping from the rad cap? If yes to ANY of these questions…then you have a bad Head Gasket…
Civics dont just over pressurize their cooling systems for fun so if that is happening…the Gasket is done. How you go about fixing it is up to you. Some would use Blue Devil at this point…Mechanics like myself will rip the head off, have it milled flat the same day, and have this puppy repaired Toot Sweet.
This is all up to you… You will know when you have a bad head gasket…ITS Rather Obvious. You stated that you removed the Rad cap off a “cooling” engine…and you heard angry noises…Well OF course you did…the system was still HOT…and Pressurized wasnt it?
You have a problem when you do NOT touch the rad cap…and you hear pressure escaping slowly past the cap and into the res… When you remove the cap w your hand…You will surely hear pressure escape…Because YOU are letting it out!
Run vehicle normally… Feel the hoses for over pressurization… Shut car down…listen to the rad and res…DO NOT TOUCH THEM…JUST LISTEN… Now do the same while running… If you get periodic gas escaping past the rad cap and into the res…you have a bad head gasket. There will be plenty other symptoms as well…such as the temp needle on the dash will go up n down n all over the place because of the air pockets introduced by the bad head gasket. Oh yes the engine will let you know when it blows that gasket.
Keep us posted… and try to keep it concise… I had an awful time reading this post
Blackbird
Pay special attention to what Blackbird said about having the heat control set on High. That opens a valve all the way so coolant can circulate freely onto and out of the heater core - so any air pockets in that area will be eliminated. The fan setting is irrelevant to this process.
You may find your Honda does not have a bleed nipple. My 1999 Civic doesn’t, despite one being shown in the Haynes manual. An alternative way of letting out air pockets is to raise the front end on ramps or jack stands, remove the radiator cap, and let it warm up and idle a good long while. Be ready to catch any coolant overflow and dispose of it properly. The stuff is lethally poisonous to any animal that happens to lap it up. After the engine cools, check the level in the radiator and overflow tank and top up if necessary. Do this again the next day after a run and cool-down cycle.
True… Some have the nipple some do not. The ones that do not need to be brought thru several Warm up…Hot…Cool Cycles in order to burp the system of air. The rad must not have any leaks…nor any hoses and the Rad cap needs to be sealing. Basically everything needs to be working properly. But several Hot cold cycles will purge the system. The reservoir needs to be filled as well…so that when the hot coolant is pushed into the Res…It will be able to pull coolant back into the rad.
Blackbird
I’m sorry for the confusing and lengthy description. I do agree it was nonsense! A jumbled mess. I’ll try to keep this simple.
The temp needle does not move and stays propped right until the symbol on the gauge. Which I’m led to believe indicates normal temperature.
Since I got the car back the radiator coolant level, directly under the cap, has not been full, not filled to the brim. It should be? Is that what you are saying?
Question about the burping… The vents in my car do blow. For a while when I turned the vents up it would make a god awful noise and smelled slightly of burning plastic. Now it emits a hum and ventilates no air so I cannot vent air through the system. The only time air comes through is from driving at higher speeds. Can I burp it given the state of my ventilation system?
I have never heard gases escaping the cap while after driving. Although the radiator hose may have been hard. I will double check both of these and confirm this with you.
You do mean this hose correct? The big one.
Also please look at these, do these photos indicate head gasket problem? If not, then what problem? Because I don’t believe this is at all normal.
That is the left of the block and then right. Just remember I’m a car newbie lol.
The mechanic assured me there was no blown head gasket. Possibly incorrect eh? There is no milky oil, no smoke from the exhaust but maybe a small oil leak to which the mechanic confirmed although not from where the leak came. And just want to add the thermostat in my car has never been changed.
I will attempt to bleed the air out based on your opinions. Pretty sure I can manage this with your advice.
Thanks guys, great help! And I hope that’s a bit easier to read 
And one more thing, is there a way to get the model number off of that radiator? As to verify it is proper for my vehicle.
If I do have a pinhole leak similar, what Insightful guessed, how long may I drive the car in this state? If I baby it will it make it for a little while? Or no way of knowing?
If I do have a pinhole leak similar, what Insightful guessed, how long may I drive the car in this state? If I baby it will it make it for a little while? Or no way of knowing?
No way of knowing. Every evening, after engine cools down, fill radiator to top. Note how much you add and if it’s getting worse (adding more).
Thanks insightful.
So I took a little 25 minute drive around town (35 - 55 mph) and did the hose test. If I have the right hose, as shown in the picture above, it was not hard although it was hot (not hot enough to burn me). And I did not hear gas escaping the cap.
Originally when I squeezed the hose and it was closer to hard I had been driving a lot and on the interstate (70 - 85 mph) for over an hour and was hot enough to burn.
Please reference my previous comment and pictures for any further advice. The nipple bleed is what I want to try next.
Your pictures appear to show oil seepage from the valve cover gasket…the least of your problems.
Your car is pretty similar to mine, a 1999 Civic. One thing that stands out for me is that hole facing up in the fitting where the top radiator hose meets the engine block. That may be the air bleed screw. It looks strangely missing a piece to plug it. Look into it and make sure it’s not open!
UGH…
That “Hole in the fitting” is the top rad cush mount…
The gasket…is the valve cover gasket…
“Burping” your cooling system has nothing to do with the air coming out of your vents…
Guys…take it from here… I’ve had a long and annoying day… Im afraid that if i respond here I will be Unkind
Blackbird
The bleed valve should be at the other end of the block where the lower radiator hose connects to the block. The hole where the upper hose connects to the head is for mounting the wire loom for the spark plug wires.
You can add coolant daily and keep driving. Eventually the leak will get big enough to find. Until then, you should be OK.
It sounds like you got it under control but not solved. Be sure to check the water pump isn’t leaking from its casing weep hole. & suggest to post a photo of the dash coolant gauge when the engine is warmed up. As part of the process suggest to also replace the thermostat, definitely if it the original that came with the car. Thermostats don’t last forever, they’ll crud up and not move freely, not open as wide as they should, not close as tightly as they should, or they’ll leak (internally, usually you won’t see this type of leak) and when they start to go bad in any of these ways it can produce weird & difficult to diagnose cooling system symptoms.
One thing that stands out for me is that hole facing up in the fitting where the top radiator hose meets the engine block. That may be the air bleed screw. It looks strangely missing a piece to plug it. Look into it and make sure it's not open!
You’re right there is nothing there, it’s just filled with crud.
As part of the process suggest to also replace the thermostat, definitely if it the original that came with the car.
So I found a thermostat I bought years ago but never installed. I know, I’m an idiot. Will throw this thing in today. There is, on the top of the piston/valve which appears to be copper (maybe?), some slight green build up. Can I still use it? It is a cheapo Stant 13878.
Go get yourself a 'stat from Honda.
Many of the aftermarket ones are junk.
Better to buy a new OEM version as posted above, but if you decide to try it out anyway, put it in a pot of heated water on the stove with a thermometer and make sure it fully opens at the correct temperature first.
