'03 civic radiator overflow problem

shadester200

Respected
5+ Year Member
10+ Year Member
Did you ever got to the bottom of it?
thanks for all the interest! I took it to a more reputable shop, they pulled the head and found that it was warped They said the previous owner probably overheated it to a point where it warped. They had the head milled and that was the end of the problem. It has run great ever since.
 


Frenchyaz

New Member
thanks for all the interest! I took it to a more reputable shop, they pulled the head and found that it was warped They said the previous owner probably overheated it to a point where it warped. They had the head milled and that was the end of the problem. It has run great ever since.
Good to know, thanks for the update!
 

hswan1180

New Member
5+ Year Member
It's great to find this thread... I bought my Civic with 175k plus miles and it always had overheating problems, not constantly but anyway... Back then when i bought it i did the basic stuff someone would do to a used car if it overheats, changed hoses, replaced thermostat and flushed the system (even removed the plug on the block that some wont do). All of that didn't really fix it and like it has happen to some of you guys there was always that possibility that a previous owner had overheated the engine. At one point i had to change the radiator fan, possibly from turning on and off more than normal it just burn out, i did tested it and yes it had to be changed.
Long story short, i do have the problems that many of you have mentioned. My reservoir is filling up, maybe about every 500 miles i have to emptied (if i want to), and if i don't it does make a little mess were the cap is but my car wont really show overheating indications till after 1k plus miles depending on driving conditions too. I do a every 1month or 1k miles inspection of fluids and tires so as long as i add fluid at that interval the car does great.

A few month ago my neighbor lend me a Radiator combustion leak test kit and we did see change of color in the fluid but it took for ever, he said if it was really bad that fluid changes color immediately... a week ago we did a leak down test and nothing leaked, so definitely is something that happens when the car is at higher temperatures. I have been driving the car like this since i bought it, but always monitoring it. The car is now 233440 still haven't fix the problem cause honestly i been procrastinating to do it...but is that time for timing belt and all that fun stuff so i will be ripping the head off and working on that... and yes guys i know timing belt is at 220k but is all good... im pushing it to 240k mostly because i had some other issues and i want it to troubleshoot the car before just starting to swap stuff around.

As i read here or somewhere else, my theory has always been that exhaust gases do slowly creep in to the cooling passage as the car is at normal operating templates, creating air pockets in the system and that air boiling and forcing fluid back to the reservoir.

*Funny thing is that i would still drive to hell with this car today if i had to go, all i need is some honda coolant just in case and good to go* Btw i do tow a Sea-Doo with it too.

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Frenchyaz

New Member
It's great to find this thread... I bought my Civic with 175k plus miles and it always had overheating problems, not constantly but anyway... Back then when i bought it i did the basic stuff someone would do to a used car if it overheats, changed hoses, replaced thermostat and flushed the system (even removed the plug on the block that some wont do). All of that didn't really fix it and like it has happen to some of you guys there was always that possibility that a previous owner had overheated the engine. At one point i had to change the radiator fan, possibly from turning on and off more than normal it just burn out, i did tested it and yes it had to be changed.
Long story short, i do have the problems that many of you have mentioned. My reservoir is filling up, maybe about every 500 miles i have to emptied (if i want to), and if i don't it does make a little mess were the cap is but my car wont really show overheating indications till after 1k plus miles depending on driving conditions too. I do a every 1month or 1k miles inspection of fluids and tires so as long as i add fluid at that interval the car does great.

A few month ago my neighbor lend me a Radiator combustion leak test kit and we did see change of color in the fluid but it took for ever, he said if it was really bad that fluid changes color immediately... a week ago we did a leak down test and nothing leaked, so definitely is something that happens when the car is at higher temperatures. I have been driving the car like this since i bought it, but always monitoring it. The car is now 233440 still haven't fix the problem cause honestly i been procrastinating to do it...but is that time for timing belt and all that fun stuff so i will be ripping the head off and working on that... and yes guys i know timing belt is at 220k but is all good... im pushing it to 240k mostly because i had some other issues and i want it to troubleshoot the car before just starting to swap stuff around.

As i read here or somewhere else, my theory has always been that exhaust gases do slowly creep in to the cooling passage as the car is at normal operating templates, creating air pockets in the system and that air boiling and forcing fluid back to the reservoir.

*Funny thing is that i would still drive to hell with this car today if i had to go, all i need is some honda coolant just in case and good to go* Btw i do tow a Sea-Doo with it too.

Sent from my SM-N920V using Tapatalk

You'll find good information here: http://www.carsdirect.com/car-repair/understanding-radiator-cap-pressure-ratings

However, in my case, the overfill radiator was getting full and one day it got emptied while on the freeway, which made me think I had a leak and I did have one. My Civic is 190k miles and I thought that my overfill tank was cracked or something so I changed it but still leaking.

I was a bit puzzled but I thought about it. The coolant gets hot, builds pressure in the radiator which opens then to let it go to the overfill tank. Coolant cools down when engine is off and it is supposed to sip back the coolant inside the radiator. If you have a hole in a straw you will have to suck harder to drink right? Same with the radiator however it is driven by its own pressure limitation and cannot increase it like we would do.

Basically, I ended up changing the bottom section of the radiator hose (it has 2 parts) and put some worm screw clamps to seal the system. After I filled up the coolant to the Max line, I've seen it going up and down like it should without going below the Max line. Problem solved.
 

hswan1180

New Member
5+ Year Member
You'll find good information here: http://www.carsdirect.com/car-repair/understanding-radiator-cap-pressure-ratings

However, in my case, the overfill radiator was getting full and one day it got emptied while on the freeway, which made me think I had a leak and I did have one. My Civic is 190k miles and I thought that my overfill tank was cracked or something so I changed it but still leaking.

I was a bit puzzled but I thought about it. The coolant gets hot, builds pressure in the radiator which opens then to let it go to the overfill tank. Coolant cools down when engine is off and it is supposed to sip back the coolant inside the radiator. If you have a hole in a straw you will have to suck harder to drink right? Same with the radiator however it is driven by its own pressure limitation and cannot increase it like we would do.

Basically, I ended up changing the bottom section of the radiator hose (it has 2 parts) and put some worm screw clamps to seal the system. After I filled up the coolant to the Max line, I've seen it going up and down like it should without going below the Max line. Problem solved.
I wish that was my problem... I had looked and check every other angle and possibilities just so i can prove that i don't need to do head work but unfortunately i do[emoji29] . Glad you got it fix.

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Frenchyaz

New Member
I wish that was my problem... I had looked and check every other angle and possibilities just so i can prove that i don't need to do head work but unfortunately i do[emoji29] . Glad you got it fix.

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Good luck. I would have tried this
if it was me and see if it fixes it, at least temporarily but I'm no mechanic lol.
 

hswan1180

New Member
5+ Year Member
Good luck. I would have tried this
if it was me and see if it fixes it, at least temporarily but I'm no mechanic lol.
HaHa nice video, it's actually very helpfull... Thank you... i'll probably end up pulling the head anyway but that was a great option.

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lunder03

Respected
9 times out of 10, if your car is back filling into the over flow tank and not returning to the engine it's because the water pump is out, head is warped or the head gasket is bad, possibly all the above. These air pockets created with a bad head gasket, etc. are what prevent the return flow as well as a possible bad thermostat.

I found the easiest way to check for a bad head gasket is to take off the radiator cap, fill it up if necessary and watch for a constant flow of bubbles. That is a clear indication of a bad head gasket.

If you continue driving the car with a bad head gasket and it continually over heats rest assure you're well on your way to a warped head if it isn't already.

Finally, most of the time the head gasket goes bad due to extremely high temps usually caused by a faulty water pump, low coolant, faulty water pump or a combination thereof.

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