Got a problem here and wanted to get some input as to what the problem might be. After driving my 1998 Civic EX (all stock, 247,000), I can open the hood and the coolant reservoir is full and coolant is slowly draining from the top. Don't believe that it's ever done this before. The car isn't overheating or running hot, and I've checked & it isn't a blown head gasket; no obstructions in front of the radiator and the cooling fan (s) works properly. After it sits for a bit, most all of the coolant is sucked back into the radiator. The only thing that I can come up with is that the (original) thermostat possibly needs to be replaced. Is there anything that I'm overlooking?? Oh, and I replaced all of the coolant hoses a year ago, so it's not a collapsed hose or anything like that. Certainly, this isn't normal? Thanks in advance for any replies!!

 

Just removed the radiator cap and cranked the car (cold) and there appears to be coolant movement thru the radiator; could the thermostat be stuck??

It seems it's either that or a headgasket issue, although there's no issue with coolant in the oil and it's not blowing white smoke etc. And I've had no overheating issues.

 

Have you replaced the cap? Sounds like the cap is allowing fluid to enter the overflow prematurely.

A tstat issue would cause you to over heat or never get warm.

 

I'm going to try that, but I'm starting to think that it's a bad head gasket. It's not bad, but it's enough to allow cylinder pressure into the coolant system. Just my luck...... BUT, the car has been a trooper and has been awesome since new. It's certainly worth repairing.

And no, at this point, I haven't had any overheating issues. But if I don't address this, I'm sure I will....................


I just checked, and even though I replaced the radiator 4 or 5 years ago, I reused the original ('98) cap, so I'm definitely going to put a replacement on just to see IF that could be the problem........

 

Tried the new radiator cap; coolant is still bubbling into the reservoir almost to the top. Looking like it's most certainly a blown head gasket & will have to be replaced. Oh joy........

 

Compression test! Last thing I would suggest doing before planning on tearing into the motor.

 

Yes, definitely gonna do that before going any further. Will also do the compressed air test as well to see if there's any bubbling in the coolant. But, it most probably is a bad head gasket; just something else to repair. That's what happens when these motors have alot of mileage on them.

 

Got the car back from the head gasket replacement 'surgery', and it seems that all is well. I examined the old head gasket and I swear, I can't see any problem in the old gasket at all. But there had to be a problem because the problem's been fixed. The head was sent to the machine shop and they did the valves and pressure checked it. I guess that there was a problem with the gasket, but you sure can't tell by looking at it. But it's fixed and that's all that matters.

 

if bubbling you mean boiling, then im pretty sure its a clogged rad. had the same problem in my caddy a few months ago. put a new one in, and havent had an issue with it since.

just saw the last post, but sounds like the exact same problem i was having. just was overheating.

ok. had to edit again. how long do you drive the car. only found out it had a problem driving it longer than 45 mins.