Accidentally overfilled coolant reservoir

[NSZteg]

I way overfilled my coolant reservoir a few months back, almost all the way to the top. At first I just left it that way and drove with it like that for a while, then I eventually got around to draining it back down to the max fill line. But now, coolant keeps filling back into the reservoir tank on it's own. I keep draining it back down, and putting the coolant back in the radiator over and over again, and it just winds back up in the reservoir.
Does overfilling the reservoir and driving with it like that damage anything? Or do you think there's just so much air in my system at this point, it just keeps pushing the coolant into the reservoir somehow?
It's an '05 EX.

 

[stcopley]

From what I understand trying to read this, you're taking it out of your resecvoir and putting it back in the radiator? Which means you will always have that amount of coolant?

 

[NSZteg]

Right, but it's not staying in the radiator. It keeps going back into the reservoir up past the max line. I took the initial overfilled amount out. Now, what should be the normal overall amount of coolant is in there, but it keeps moving into the reservoir.

When I see the reservoir is too full again, I always check the radiator, and it always needs coolant. So I'll empty the reservoir, put what I emptied into the radiator, and then the whole situation happens again, the reservoir will be filled again past the max line after some driving.

 

[AlaskaB16]

Purge/burp the coolant system and make sure all the air is out. Is your car over heating at all? Watch the gauge and see if it's above normal.

 

[NSZteg]

The temp needle has gone up almost into the red zone a couple times, but the vast majority of the time the needles right where it suppose to be. I think when it jumped those few times there was just a pocket of air at the coolant temp sensor.
There are times when I can't get any heat out of my blower when the cars just sitting, like at a light. But when I get moving again the heat will come back.

 

[AlaskaB16]

Well there you go, when the car over heats, it's sending coolant into the over flow. You better get that solved quick or you'll warp the head. Last time I had an over heating problem it was the head gasket.

 

[sr6000]

Check your head gasket with a leak down test

 

[mymmeryloss]

How old is the radiator? Thermostat?

 

[cvcrcr99]

My guess is the cap is faulty and needs replacing. The cap controls coolant going to and from the reservoir.

 

[AlaskaB16]

^^ The cap is a good one. Easy and quick to test if it's doing it's job of opening/closing at the correct temp.

 

[TokyoSkies]

Sounds to me like a sticky thermostat. I'd check that first, as it's easy.

 

[NSZteg]

Are you guys talking about the radiator cap or the cap on the reservoir?

I have since I started this thread changed out my thermostat, and the problem is still happening.

 

[00siboy]

As the engine heats up and the cooling system builds pressure, the cap releases pressure (coolant) into the reservoir. When the engine cools down again the coolant is pulled back into the system. If a cooling system is working properly there should always be coolant filled to the top of the radiator when the cap is taken off. It sounds like you are losing coolant either because your cap is not holding enough pressure and letting too much coolant out or you are overheating due to a leak or bad headgasket which is why the level is always low in the radiator. Putting too much coolant in a reservoir will never cause a problem.

 

[NSZteg]

Wow, I didn't realize the radiator cap was so proactive in moving coolant like that through the system. I'll try a new cap next, I'll let you guys know what happens.

I took my car to a local garage a couple months back to have them find the problem, they had the car all day, charged me $130 in labor and for some coolant, and they couldn't find the problem. I was pissed. They said they tested my coolant for hydrocarbons and found none, but I can't even trust that they did that, because at the time I also had a bad battery, and they told me I needed a friggin new alternator. I said no thanks I'll wait on that. I later hopped on Youtube, learned how to test my alternator, and it tested out fine. I then just bought a new battery, and all's well. Never going back to that place!

 

[Kenneth]

Yep. Just resolved the exact same issue on my civic. Turned out it was a bad head gasket. But you gotta hope it's something easy. You've probly got some air in the system, after all this. It's not likely that's the real problem. But it should be addressed. I'll tell you the same thing I was told. Get a block tester. You get those on the loan a tool program at o Reilly, or autozone. Test before adding coolant. Buy a new cap, then burp the system. Hope it ends there. If not, move to the next test. Keep us posted. Good luck!

 

[NSZteg]

I have burped the system, about 4 or 5 times over. The last time I added some Stop Leak, filled the radiator, burped it, and now the coolant's up over the max line again. I bought one of those Lisle funnels that attatch to the radiator, you pour some coolant into it, the bubbles come up as you run the car, the coolant goes in and your set, it's sweet.
I'll be doing it all again tomorrow, heh. And putting a new rad. cap on afterward. Damn I hope this works, this is my winter car, winter's coming soon, and I don't want to get raped at the dealership to get this fixed.

 

[Kenneth]

When I was adding coolant, I noticed bubbles. More than would be expected, as the system was circulating. Just when I thought it was fully purged of air. Couple more bubbles. Also as the front of the car is elevated, to help purge the air. The rear of the car goes down. So lots of moisture in the exhaust, made a big wet spot on my garage floor. Both these things made me suspicious. So I tried the block tester. I tested several times, nothing. Next was the leakdown test, and also looking into the cylinders for coolant. Yep there it is. Hope your outcome is different, that's about 1200.00$ at the dealer. My problem started the same way. It was spittin coolant up from the overflow. Try that block tester first though. They charge a refundable deposit, so it's free and it's easy.

 

[NSZteg]

So I bought a new cap, burped the system again, drove it some long distances, and the damn coolant is going into the overflow again. Cap didn't solve the problem, neither did some Stop Leak, neither did a new thermostat.
I am getting a wet spot on the ground at my exhaust pipe too, but I thought that can happen even when everything's fine. Also, all these times (about 5-6 now) that I've now burped the system, the bubbles never completely stop coming, so it may be the head gasket after all. I don't know how the hell that would have happened though, the car's only an '05 with 112K on it.

 

[Kenneth]

Sounds familiar, hope it's not but just in case it's the HG. plan on a new timing belt, water pump, probly ought to think about re doin the valve train. Your gonna be right there at all that stuff. Gonna add to the price a little. But you can save money by buying parts from majestic. Doin it now saves money later.

 

[taluzer45]

My civic done this too, HG was gone, these 7th gens are so damn tempermental!