Rep Power: 0

2001 Honda Civic ex, Auto tranny 188k miles. I’m losing coolant without any puddles under the car. Block test was clean, oil is clean, no sweet smell in exhaust . Recently replaced cam sensor, valve cover comes off during, everything looked good. Burped cooling system by letting it run with heat on full blast while topping off coolant in radiator until level stayed the same, filled reservoir to max, no bubbles once the level stayed the same. Drove for an hour parked it, coolant level didn’t drop. Drove it 30+ miles the next day, coolant didn’t drop. Took the cap off and checked level in radiator and it was good. Next day coolant dropped in reservoir by more than half, rad level was still good. Burped and topped it back off today, presumably issue will repeat. ANY HELP??? SUGGESTIONS??

 
Rep Power: 120

What do you mean by “next day”? Was the car driven or parked?

Car stayed parked, take the radiator cap off the next night. If the reservoir drops again it has a crack, if it’s full and the radiator level dropped you have a leak.

If the car was driven , and you have a completely full coolant system and a overfilled reservoir, then as the coolant heats up it will push coolant out of the reservoir. Once the system cools, it will pull back that coolant and you will have a air gap again in the reservoir. That’s why your not expected to fill it past the bottom line when cold.

 
Rep Power: 0

Car was driven 30+ miles parked for the night. Checked after drive and when cooled down, no loss. Next morning over half down. No puddles under the car. Was filled hot.

 
Rep Power: 230

Headgasket breach, drinking coolant? (Usually these blow coolant out of the reservoir though)

The reservoir can stay on full while the coolant is hot, even if the coolant is being consumed. Then when it cools inside the radiator it will pull coolant from the reservoir.

 
Rep Power: 0

Checked hot and cold and didn’t lose coolant until it sat a night. I don’t have a clue

 
Rep Power: 225

When you filled it with the cap off and heat on did you also raise the front of the car? Maybe an air pocket is still trapped in the system?

 
Rep Power: 0

No I didn’t not, do you think and air pocket would make it lose more than half from the reservoir to the rad? I’m about to check and see if any is lost today.

 
Rep Power: 0

Dissent appear to have lost any since I burped and filled yesterday, been drove the same distance. Only difference is when I checked last time before it lost coolant I took the rad cap off and checked. Not going to this time and going to check again tomorrow to see if any has been lost. Idk

 
Rep Power: 0

Please help I bought an 02 civic with only 145,000 miles. I started having issues with the car overheating and blowing coolant out the overflow tank, and the heater blowing out cold air when the temperature gauge starts rising. I replaced the radiator, radiator cap, thermostat, water pump, head gasket, overflow tank, both upper and lower hoses, and both coolant temp sensor and fan sensors. I drove it for a few days and the heater stopped blowing out hot air again and coolant sprayed out the overflow tank, and the heater stopped blowing out hot air again. The temperature gauge did not move but I am still very concerned. This can not just be an issue that I can not fix, so can someone please assist me with what more I can do?

 
Rep Power: 223

Either you didn't bleed the coolant properly, or when you did the headgasket it wasn't done properly (head wasn't machined, non OEM gasket used, etc)

 
Rep Power: 0

Sent the head to get machined, and used OEM gasket, bled the system following proper instructions. There was never an issue with the headgasket, I just replaced the water pump and decided since I was doing all that I might as well do the head gasket. There is absolutely no signs that the head gasket was cracked or warped. I have pressure checked the engine which there are no issues. There has got to be some where else that that fluid could be getting air and over pressurizing.

 
Rep Power: 223

How did you bleed the coolant?

 
Rep Power: 211

When you say you 'have pressure checked the engine', do you mean the standard radiator pressure test or Ezone's test where each cylinder is pressurized to at least 150 psi and the radiator is checked for bubbles?

 
Rep Power: 0

topped off the radiator fluid, turned the car on and turned the heater on, then ran the engine until the fans kicked on twice and topped off the fluid until the bubble came to a minimum and fluid stopped going down.

 
Rep Power: 0

Sorry didn't mean to say engine, pressure tested the cooling system and held pressure.

 
Rep Power: 223

Need to get the nose as high as you can and use a spill free funnel

Need to pressurize each cylinder to 150 psi or more and watch for bubbles coming out of the rad

 
Rep Power: 0

Hi Kt2182, I'm new to this however. I'm going through the same issue. Could you tell me how you ultimately fixed this?

 
Rep Power: 223

Most likely your headgasket

 
Rep Power: 0

I appreciate you responding thanks. I've been consistently burping my 02 civic every 2 weeks. New thermostat, new radiator, new radiator cap, water pump 2 years old only 20k on it, system holding pressure, no signs (NONE) of a head gasket, and YES the front end is raised on blocks every time. I burp it, it's good for about two weeks, then starts blowing cold, starts to over heat, then I burp again and fine. I have to add coolant every time, but cannot find a leak. And holding pressure.
Oil is not milky, no smoke from trail pipe, no gurgling in radiator or reserve.

 
Rep Power: 223

Read and perform the test in here with compressed air

https://www.civicforums.com/forums/3...reference.html

These cars don't fail in the typical way for headgaskets.

 
Rep Power: 225

The only other option that could cause air to get into the system is an external coolant leak. But you say there are no signs of a leak. Fluid level in the coolant reservoir would be key.

 
Rep Power: 0

Good morning, thank you for the reply. So I double checked the coolant res. This morning and it was slightly above the MAX line. I burped again yesterday, and everything is fine now. But this is what happens, this will last 1 1/2 to 2 weeks and then I have to burp again. I have a question, does the length of time signify anything. It looks like most head gaskets, or people with almost the same symptoms, People are losing coolant fast, and mine is literally almost 2 weeks exactly.

 
Rep Power: 368

go to the link posted, read it and watch the videos in the first post. Don't spend time in anything else other than doing the tests posted there.
that will stop your denial.

 
Rep Power: 0

Lol you're absolutely right. This has all been great. The only difference I noticed was the length of time.
Anyone on long Island able to do this job? I don't think I'll be able too.

 
Rep Power: 225

The head gasket leak can start small and worsen over time. Unless you can find a small external coolant leak, I would believe it's head gasket.

 
Rep Power: 0

Ok, understood. Thank you all.
I believe this may be our of my skillset.
If anyone would be available to quote doing this job I'd appreciate it.

 
Rep Power: 127

Entirely depends on whether your head’s warped or not. You’ll have to call around.

 
Rep Power: 0

Copy that. Thank you for the heads up.

 
Rep Power: 225

A shop will probably charge $1-1.5k for a head gasket job. You're a long ways away or I would offer.