Rep Power: 0

so i have a 2003 civic lx coupe. recently i’m in a situation where i loose coolant within about 45 mins to an hour of driving and it’ll overheat because there’s no coolant. this car is stock. everything’s all original that would matter in this situation. it has 156k miles currently. i’ve owned it since 92k miles

everything that i’ve tried and i still have the same issueall the things i've tried:

• compression tests on all 4 cyl were (facing the car) from left to right 180psi, 170psi, 150psi, 180psi
• new thermostat put in about a month ago
• new headgasket done about 20k miles ago
• did the radiator combustion leak test with the fluid and no reaction was detected - stayed the same color and no reaction was observed
• the top radiator hose gets hot so everything is flowing and the thermostat is opening up when coolant is in the system
• passenger floorboard is not wet at all and i do have heat so that to me that rules out the heater core
• i gave most of the coolant hoses new or different hose clamps and have gone over them many times
• the fans work seemingly. they're on when the ac is on and jumped them from the connectors to the battery and they work if you were to wire them to run with an ignition source
• timing and water pump, believed to be a gates kit if that means anything to you guys and was done at 102k miles so like about only 50k miles ago
• did a pressure leak kit and that would would loose pressure but i could not find why or where it was loosing the pressure other than, it did. (but presumably leaking from the kit itself but that was the only one they had and that’s the only oreilleys near me)
• i do smell coolant through vents and or outside but that is with both heat and ac on
• i've replaced the radiator cap yesterday as well and still didn't fix the issue
• not seemingly seeing any puddles on the ground
• no white smoke out the exhaust

 
Rep Power: 0

Have you pressure tested the radiator itself? I'm wondering if you have a hairline crack on the core, that's not making it to the ground.

 
Rep Power: 368

only test that works to detect headgasket leaks is this one, don't waste time or money in anything else.

 
Rep Power: 0

yes i did. rented it through oreilleys and i did end up finding a small leak on the top hose and that’s when i had gone over the other hoses and put some new or different hose clamps on the hoses. while i thought that had fixed it, did the pressure tester again and it held pressure and so i returned it, but on my way back after returning it, it had overheated again. got home and no coolant

went back the next day, looked like i was given a different rental and it would loose pressure but unsure if it was the kit itself or the rad/hoses itself that was leaking but i’m like 99% sure it was the kit i had rented loosing it’s pressure. ran out of weekend time and haven’t done anything since. planned on going to a completely different store in a different town and renting another from there today or something

 
Rep Power: 0

ill have to try that this week if not this weekend. did see this video in a similar forum last night and had saved it to try it out. really appreciate it!

 
Rep Power: 0

i had did this today and it did nothing.. no bubbles no rising coolant levels. did a leak down test as well and all cyls were at 20%. put some gasket sealer on the thermostat housing. filled coolant back up and took it for an hour drive around town.. still is overheating and loosing coolant :/

 
Rep Power: 225

Where is it losing coolant? Out the top of the coolant reservoir?

 
Rep Power: 0

well, that’s the issue. i have no idea where it’s going. it’s not wet anywhere i can see. if it was leaking out the reservoir it’d be wet and in the battery holder and it’s not. as far as headgasket, we’ve done every test imaginable from compression test, leak down test, the combustion fluid test, pressure test on the rad (though i think the tester was faulty. i do plan on going to a different town and renting the tester this weekend.) and the one test another person had sent previously in the thread. and that test came back with nothing and everything normal. so i’m pretty much at a loss

 
Rep Power: 512

Get it up on jack stands, start the car, let it get to temp, and get under it with a flashlight. If you're actually losing coolant, you should see steam leakage.

Dummy check, safe to assume you bled the absolute **** out of the coolant system and you're not just a victim of hidden bubbles in the coolant system?

edit: I was a victim of big *** bubbles in the coolant system. Only reason I ask. I bled the coolant system and let it run for 10 minutes watching for bubbles to come from the radiator before calling it full and that solved my "overheating" problems.

1. Park with the front at an incline and pop off the rad cap. stick a radiator funnel in (like in that test video sandro posted). If coolant level is low, top it off before you start.
2. start the car, let it get to temp, topping off coolant as the level drops.
3. rinse and repeat as level keeps dropping/bubbles appear
4. once you observe no more bubbles in the funnel, keep it running for like another 5 minutes.
5. Because I'm neurotic, I reset that 5 minute timer ever time I saw any bubbles come up. If you're extra neurotic, make that 5 minute timer longer.

optional step: while you're waiting, use a flashlight to look around for any potential steam leakage from non-conventional places to further rule out other sources of coolant loss. some places might be hard to see, like between the intake mani and the block itself. The last time my head gasket blew, that's right where it was at.

 
Rep Power: 0

yes i’ve done this. i even have the fancy funnel to burp the system. ran for well over 20-30 mins. kept jacking it up in down (i heard the heater core is higher than the radiator and jacking it up help’s stubborn bubbles) but i would jack it up, watch bubbles. drop it, jack it up, watch bubbles. would rev it, watch bubbles. etc. til it stopped and didn’t see anymore. then would take it on a drive and bout 45 mins later the coolant would be gone and it’s overheating and right before the gauge starts overheating you’ll smell the sweet coolant smell.

and as far as the headgasket wasn’t done not too long ago as i had pretty much the same exact issue but instead it would blow the overflow cap off but this isn’t happening in this case and all the tests under the sun say it’s fine. so i’m still pretty adamant that there’s a leak somewhere. this weekend i’m going to try the dye and rent another radiator pressure tester from oreilleys again and see if i can find anything else.. if not i’m not sure what else to do after that. this cars been pretty reliable but when it breaks in anyway it’s always a PITA

 
Rep Power: 368

if it is not the overflow tank, then somewhere else. Clean engine and do the die test

 
Rep Power: 225

The heater core could also be leaking but you should notice coolant inside the cabin. If no external leaks, could be the headgasket letting coolant into the oil (although this failure is rare).

A previous 7th gen Civic I had showed no bubbles or overheating while idling in my driveway. However, after a two mile drive down the road and back the reservoir would be well above where it previously was.

 
Rep Power: 0

not wet and no signs of wetness on the floorboard or up into the dash.

oil is perfectly fine. it’s loosing a decent amount of coolant and i feel would be pretty noticeable and oil looks like how it should

 
Rep Power: 225

If the head gasket was not installed properly maybe coolant is leaking into the cylinders and burning off. However, this would be unlikely. Did you do the test where you pressurize the cylinder with an air compressor and watch for bubbles coming out the radiator? Or just the engine running and watching for bubbles?

 
Rep Power: 0

yes i did with the air hose and you put it at TDC and there was no bubbles through the rad and we’d wait about 5 or so mins on each cyl. also did a leak down, all cyls were at 20% (well within the green), compression test from left to right was 180, 170, 150, 180. which that’s pretty normal. did the fluid combustion test with the fluid reaction and that had no reaction at all. so no combustion gasses are getting in through the rad. so all that rules out a headgasket to me and then no wetness on passenger side for the heatercore so that rules out the heatercore to me. so i feel it’s gotta be leaking onto something hot therefore there is no puddles under the car. but then again i have no idea honestly

 
Rep Power: 368

do you see "smoke" out exhaust when accelerating when engine cold? color?

 
Rep Power: 0

nope no smoke at all under any circumstances. cold, hot, fast, slow, reving etc

 
Rep Power: 368

honda cap on radiator? I think that caused some issues in some cases. Same for Thermostat (Ah, I think there are two temps in them too)

 
Rep Power: 368

ah, what about the hose between radiator and overflow tank?

 
Rep Power: 512

Dude would see evidence of leakage if the coolant loss was there

 
Rep Power: 223

That 150 psi is probably the problem cylinder.
either try the headgasket again or throw another motor in it