Rep Power: 0

Situation:

2005 Honda Civic LX manual
Got the car in 2015 at 103K miles
I’m currently at 197k

Old radiator was leaking for a while and I would just add distilled water as needed as I live in the SW and it never freezes. Finally decided to replace it and I installed a Mishimoto Radiator, all new radiator hoses, new overflow tank and Honda Genuine Thermo (unsure if I installed the jiggle valve at the 12 o’clock).

Problem:
After about a week or two of driving around, the overflow tank get filled to the brim with coolant and doesn’t seem to get sucked back into the Mishi radiator. It starts leaking all over.

This has happened to me twice now.

This last time, once the vehicle cooled, I removed the cap, heard the vacuum as the air escaped through the now open hole and the level isn’t to the filler neck as I had it when I filled and bled the system.

i have one if those no-spill coolant funnel kits that I used to fill the system. I install the funnel, add my coolant until no more bubbles come out, squeeze the hoses and get more bubbles to come out, turn the car on, fill the funnel and never let it get empty, leave the car on for like 15 min and let the fans come on and off while always maintaining the funnel full of coolant. I never let the funnel get empty throughout this entire process. I wait until no more bubbles come out and remove the funnel and everything, inspect that the coolant is to the filler neck and add the cap.

The second time is refilled and bled the system, I didn’t even fill the overflow tank at all thinking that the displacement of coolant from the radiator when it gets hot and cool will even itself out. The overflow tank got full and began spilling after about two weeks.

im not sure what’s wrong. I have the Mishimoto radiator and the radiator cap that came with it. It’s a 1.3 Bar cap. I think it’s 12PSI or something; standard pressure. The new coolant tank was installed correctly as is the overflow hose.

Any troubleshooting help?

 
Rep Power: 0

Dude, I’m having this same issue.

I haven’t replaced my HG since I got the car (2005 Civic LX manual in 2015 at 103K miles; currently at 197K) but my coolant reservoir seems to overflow but won’t get sucked back in. Maybe it’s a faulty radiator cap?

I installed a new Mishimoto aluminum radiator, new hoses, new Honda Genuine thermostat, did the timing belt, water pump too.

I filled and bled my coolant to the filler neck on my radiator and purposely didn’t add ANY coolant to the reservoir tank. About two weeks later, I check the level just to see and noticed that the reservoir was so full and had already spilled all onto the engine bay (dried coolant marks everywhere). I checked my coolant level in my radiator and it was indeed not to the filler neck anymore. Like an inch or two down.

I dunno what to do or what it could be either. I’m thinking maybe Mishi sent me a bad radiator cap.

 
Rep Power: 126

Try replacing the rad cap, but if you read the thread, you know what it probably is.

 
Rep Power: 126

My thoughts, as everyone else’s will be, is that the head gasket has failed. If I were to guess, coolant level dropped too far and the car overheated.

 
Rep Power: 224

Almost certainly a bad head gasket.

 
Rep Power: 224

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

 
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Went to Honda dealer today and got an OEM radiator cap to see if it would fit the Mishimoto radiator and of course it doesn’t.

I refilled the radiator with a no spill funnel, and this time let the fans cycle 3 times. I just turned off the car and left the no spill funnel on there with coolant and am gonna leave it overnight. In the morning, I’m going to drop the car, remove the funnel, put in the Mishimoto radiator cap that fits, and put just a bit of coolant in the reservoir. I’ll probably buy one of those exhaust gases check kits for the radiator and see if it changes color.

If this doesn’t work and the reservoir keeps overflowing and not getting sucked back in, then I’m uninstalling the Mishi radiator, installing an OEM, filling and burping the OEM radiator, using the OEM rad cap, and if THAT doesn’t fix it, then I’m checking if it’s a head gasket. Frick it.

 
Rep Power: 0

So about two years ago, I was driving to AZ and I pulled off the freeway and my temp gauge went way up. I was in a Jack in the box drive through (some fast food place) so I couldn’t really pull off and turn off the car so it was like super hot for 15 minutes. Rip dude. I drove back home with it like that and on the cold freeway speeds, the temp was normal even though the HG had probably already gotten screwed up. As soon as I got home, I turned the car off immediately, I parked it and shut it off; next day, checked my coolant (distilled water) level and it was super effing low. Like less than a liter.

I guess it came back to bite me after all. I guess I’ll take it to a shop and ask if they could confirm it’s the HG and I’ll be changing out my HG. Lol.

 
Rep Power: 222

Do the test in the video posted earlier, that will tell you if it's bad or not

 
Rep Power: 367

doing the test is way easier than replacing radiator. Just do it

 
Rep Power: 0

The shraeder valve test video or the other one?

As I was bleeding the air yesterday with the no spill funnel attached, I’d manually pull the throttle and every time I gave it a good amount, bubbles would come up.

But I’ll try it the test without the Shraeder and see. Thanks for the feedback. And I have read the entire thread you made for the cooking issues. Very good info there.

 
Rep Power: 222

Putting shop air to the cylinders

 
Rep Power: 224

Pretty easy to test yourself. A couple methods in the link I posted.

 
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I’ll definitely be doing one of those tests this weekend man. Thanks for that link. I appreciate it.

 
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Is there a link to the snap on (or similar) product that fits into the spark plug threads for that air compression test?

 
Rep Power: 222

Buy a compression tester and some brass fittings to adapt to an air line

 
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Will do. Thanks for the help everyone.

Is the HG a pain I. The *** to change? I’ve seen videos and all and I’m by no means a “pro.” But—you know, nvm. I’ll just keep exploring on these forums before
1
sdaidoji's Avatar destroys me. Lol

 
Rep Power: 126

Not really, but take the cylinder head to a machinist to ensure it hasn't warped, and if it has, to get it flat.

Many of the issues with people having recurring head gasket failures is because they don't address everything. If you want a hassle-free process, check everything. Don't just change the head gasket.

Shop will do it for around $1500. DIY can be done for as little as $300-ish, assuming everything else is okay.

 
Rep Power: 367

and OEM gaskets

 
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And I'll repeat:
Use oem gaskets and parts

 
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Sweet. Will all the info be found in RiceBoy’s thread for the DIY HG change?

https://www.civicforums.com/forums/1...arts-list.html

I will definitely be taking the head to a shop to ensure it’s not warped and to fix it if possible if it is. Recently, I changed the timing belt, TB tensioner, water pump, thermostat (Honda Genuine), power steering belt, AC/alternator belt, radiator (Mishimoto), radiator hoses, timing belt upper and lower covers (mine were so broken) and changed the MTF.

Just not sure what the “you might as well change while you’re at it” parts are.

 
Rep Power: 222

Define recently

 
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All this I did about 2,000 miles ago

 
Rep Power: 367

then the headgasket (and the valve cover one)
adjust valve lash
shop might do a valve check while at it if you ask for

 
Rep Power: 0

Perfect: You got it bub. I’m gonna start researching on HGs and parts and all that. And then HOPEFULLY my coolant will flow back into the radiator. I’ll be so damn amazed if it does. It will be Like a miracle. Lol