Honda Civic 2000-2005 Problems

chiburbschiburbs Member Posts: 2
edited May 2010 in Honda
Since fall I have had a progressively worsening coolant leak. The problem is, I and two mechanics cannot find it.

They've replaced the thermostat, the hoses connecting the radiator and the radiator cap. No difference. They've tested the oil for any traces of coolant. No traces. They've let the engine cool for about 5 hours and pressure tested it. Nothing apparent.

The leak loses antifreeze over months but seems to be speeding up. I've noticed the heater stops working a few days before the engine begins to overheat (so I put in coolant). There aren't any puddles under the car.

Leak sealant seems to have helped the problem before, but I am not sure it is now.

The overheating also seems to happen in the pauses after long trips. I took a 70 mile trip today, and then it began overheating when I got off the expressway. I had checked the antifreeze levels before I left but haven't checked after because it is too dark.

There was something new today. I also smelled a bit of a chemical smell towards the end of the trip but not during it. Of course, I also went through an industrial area.

There is also no apparent wet spot inside the car and on the floor under the dash, where a leaking heater core would create that mess.

Any suggestions?


  • cz_75cz_75 Member Posts: 7
    The radiator is a three-piece assembly with plastic top and bottom tanks held on by crimped metal tabs. It is likely starting to separate because of vibration and fatigue. Look around for a one-piece radiator with a good warranty and see about replacing it.
  • kb25kb25 Member Posts: 1
    I have an 03 Civic Ex.. I bought the car during winter, loved it... As it start warming up outside it started overheating.. No sign of a leak anywhere, just a faint smell of burning antifreeze.. Started adding antifreeze here and there, checked oil, watched for white smoke out of the tail pipe...

    Also replaced the thermostat, got the hoses checked, changed cap, nothing worked.. A buddy looked it up on some software he has for cars and it had like 7 hits for a cracked head gasket.. Then about a month later my radiator blew as I was pulling into my driveway.. Ordered a new one, just got it put in. I still don't know if it fixed the problem because when i started it after getting the radiator put in, my instrument cluster went out... No luck.. But I will let you know after I figure out the instrument cluster...
  • Kirstie_HKirstie_H EdmundsAdministrator Posts: 11,123
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  • confused06confused06 Member Posts: 3
    2005 Civic - Overheated in June when I stopped after a 2 hour trip. Took car in and couldn't find anything. Replaced Radiator cap, checked hoses and thermostat but everything OK. Last week noticed the heat would not come on right away and then faded in and out. Took it back in and they have now found a "Leaky" Head Gasket. Said the gasket is not cracked but could crack if car continues to overheat. Haven't had another over heating since 1st incident. I'm hesitant to fix the gasket until I can find out what caused the overheating. My mechanic is telling me that the overheating probably caused the leak in the gasket. Does that sound right to any of you. Your problem sounds similar. Not sure what to do!
  • davidkidwelldavidkidwell Member Posts: 1
    I'm having the same problem with my 2002 Civic. It's leaking coolant but my mechanic can't find the leak. Did you ever find the leak?
  • mrposeymrposey Member Posts: 1
    Sorry to bother you. I was wondering if you ever located that leak. I have a 2003 honda civic and I and 2 other mechanics cannot locate the leak. I can get about 120 miles out of it till it overheats/runs out of coolant. I changed the radiator cap because the reservoir was filling up and I changed the thermostat just because.
  • chiburbschiburbs Member Posts: 2
    someone sent me this, which turned out to be right:
    The radiator is a three-piece assembly with plastic top and bottom tanks held on by crimped metal tabs. It is likely starting to separate because of vibration and fatigue. Look around for a one-piece radiator with a good warranty and see about replacing it.
  • solonicasolonica Member Posts: 1
    Yes this car have a head gaskets problem like the subarus. I just bought one and it over heated on a long trip. I had to do a head gasket repair and sent to cut the head. so, that's the main problem on it. So good luck and keep and eye on does head gaskets.
  • davemartinwooddavemartinwood Member Posts: 1
    edited December 2011
    I have a 2003 Civic EX at 175k miles. I had a slowly progressing over-heating problem also. I replaced a sometimes failing A/C radiator fan, after replacing the thermostat and both old upper and lower hoses. Eventually, I replaced the radiator and the overflow bottle trying to find out where all my coolant/water was going. I would consistently lose a quart of water to work (45mi.) and again on the way back. Even when watching it in overheating mode, :sick: there were no obvious leaks. I eventually am doing a head-gasket replacement. I have it apart now and the gasket and head look pretty good for 175k. I was disappointed when I didn't find the obvious gasket burn through I had expected. But, it seems that this engine (D17-A2) lasts forever until an eventual mystery coolant leak occurs. It also seems that most folks find a head gasket replacement fixes the problem. I plan to increase the head-bolt torque to 55-60 lbs/in., as some do, when I put it all back together this weekend. I'll update with the results. Keep motoring.
  • jlabine9999jlabine9999 Member Posts: 1
    @ DaveMartinWood:

    My 2002 Civic EX with 175k miles is behaving the same as yours. I've only replaced the thermostat & added coolant. Worked great for one week, then it was overheating during a 30 mile drive. Towed car to trusted mechanic & he couldn't find any problems. He added coolant from loss due to overheat. Burped the system in 65degree shop for 40 minutes. Civic worked just fine for one week. Then during a 50 mile drive....overheating again. PLEASE let me know if you figure out this problem.

    I would appreciate an email direct: [email protected]
  • Kirstie_HKirstie_H EdmundsAdministrator Posts: 11,123
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  • rondathehondarondathehonda Member Posts: 1
    I've done everything that everyone else has done here from thermostat to head gasket and the car is still loosing coolant. The mechanic thought it was the water pump. This is water pump number two. Use the copper stuff which worked for awhile. The care has 200,000 miles on it. This has been going on for awhile.

    If the car goes above 60, that is where there is most fluid loss. There is NO dripping at this point or coming through the radiator cap. There is no white smoke. There is no water in the oil. There is no water in the cylinders. The car drives smoothly as it did when I bought it. At this point, I'd just like to know what it is.

    Any ideas appreciated.
  • dave10239dave10239 Member Posts: 1

    Did anyone ever get a answer to this? I have the same problem but im losing oil after doing the haed gasket the mech did the head twice and it still has the same problem and its getting worse.... Anybody .lol

  • gcastro239gcastro239 Member Posts: 2

    Had the same problem with my 03 civic ex. The mechanic found that a plug that connects to the air box area was loose and plugged back in. He said this would happen because it was loose and said something like the thermostat would not be able to work properly by not being able to read what the sensor is telling it to do. I'm not a mechanic so my explanation isn't great. Try some the plugs that are around the air filter system. That should take care of the problem. Good luck.

  • gcastro239gcastro239 Member Posts: 2

    My explanation was for the problem with the heat initially coming out warm from the vent but then coming out cold afterwards while the thermostat is reading a normal temp and no leaks.

  • strokeherstrokeher Member Posts: 1

    My 2003 has 260378 miles on it and I started having the same probem. I have changed the water pump, themostat, hoses, radiator and the radiator being the last it went a week before overheating again. I find it hard to believe the mechanics can't find what's wrong. I drive 35 miles one way to work and I have to add fluid in the morning before I leave and in the evening before going home and can't find no leaks and the oil is clean.

  • mkooniemkoonie Member Posts: 2
    I, too, have a 2003 Civic that is losing coolant and overheating. Rose has 149,000 miles. Oil is clean, doesn't bubble when the radiator cap is off, replaced the thermostat, replaced the sensor that tells the fan when to kick on and cool the engine. Had the routine water pump and timing belt replaced last summer. I'm putting coolant almost every single day and I'm getting to the point where I am nervous to drive my car. :( The Honda mechanic said 2003s are known for this. So where isn't there a recall if so many of us are having the same problem?
  • mkooniemkoonie Member Posts: 2 Why isn't Honda offering this to the 2003-2005 models who are experiencing the same thing??? :(
  • ajandaajanda Member Posts: 1
    2002 Acura EL 1.7. I'm having the same issues. Wondering if anyone has found the key, there must be a solution right?!!!

    Thermostat changed twice, hoses done, cap replaced, fans tested, rad replaced, a gas test done resulting in engine being changed. Just when I fianlly thought we solved the problem. Overheating again with rad fluid spilling everywhere. Getting rather discouraged. I have always been a Honda fan. I'm beginning to change my mind about that. Any suggestions are welcome. 
  • jimmy_zelskijimmy_zelski Member Posts: 1
    My girlfriend has an '03 Civic that started overheating out of the blue. She first experienced the heater blowing cold air thing, and luckily she knew to shut the engine down as soon as she noticed it starting to overheat. Turned out to be something very simple. The little hose connecting the radiator to the coolant overflow tank had come off. This meant when the engine heated up coolant was coming out where that hose was supposed to have been connected, but when the engine cooled back down again it couldn't suck the coolant back into the radiator. She never saw evidence of a leak, presumably because it was mostly happening as she was going down the road and evaporating quickly. As a result she lost coolant slowly until it was so low as to cause overheating.

    I reconnected the hose and put a zip tie on it to make sure it doesn't come off again, then bled the cooling system. It's very important to bleed the cooling system on this car as it does not like air in the system at all. Some cars have bleeder valves at the top of the engine somewhere but I don't think this car does. So to bleed it, do this:

    1. Wait for the engine to cool down completely
    2. If that little overflow hose is disconnected, connect it back up again
    3. Remove the radiator cap
    4. Top off the radiator with coolant. Leave the radiator cap off
    5. Start the engine and turn the heater on full
    6. Monitor the coolant level as the engine runs. As bubbles escape and the level of coolant drops, keep topping it off. It might take 15 minutes or so before all the air escapes from the system and the coolant level stays at the top.
    7. Put the radiator cap back on and check the overflow reservoir for proper level.

    That fixed my girlfriend's problem.

    One more thing to check if the above is not your issue - there is a molded coolant line running from the top left side of the engine around the back to the air intake area. There's two of those molded lines in the intake area. They can develop pinhole leaks. To check them you'll have to remove the battery, the air intake resonator box and the air filter housing. Search Youtube for videos showing how to do this.
  • jo_2005civicjo_2005civic Member Posts: 1
    i am having problems with my 2005 Civic.The cooling system will start to have an odor then the thermostat will register hot, then cold. It would take a long time for the car to warm up and the air would run cool. When I looked under the hood, some of the coolant spilled on to the fan from the coolant reservoir. The radiator and the reservoir had coolant. The manic could not find out what the problem is but bleed the line and it worked for a while. Now, it is doing the same thing. These are the most recent problems. Last year, I had the Thermostat changed and the water cooler twice. It stops for a while then starts back up. What can I do? What I tell the mechanics to do?
  • Keith1971Keith1971 Member Posts: 1
    I have an 02 Civic and the radiator is splitting at the top and was going to try and repair it. Was wondering if stock radiators for them are copper or aluminium? Thanks
  • Littlewing87Littlewing87 TXMember Posts: 2
    How often should i change my oil on an 03 honda civic lx that just hit 186,080 miles and is about to be driven at least 80 miles per day due to commuting for new job? Should i be expecting some issues no matter what? Already have a few unsettling cues popping up but i dont know anything about cars and could easily be mistaking nothing for something. Dont have money for check up at the moment so need all the helpful tips i can get until im able to have it professionally examined again... please and thanks to any info/opinions offered on this specific car and situation 
  • Littlewing87Littlewing87 TXMember Posts: 2
    edited May 2019
    Ok check that, i have officially found what looks like several leaks from the spots found in my driveway, i ran over a peice of something the other night on a busy highway going over 70 at night and it was a significant hit on the undercarriage, but then nothing else happened the rest of the way, we drove it another 45 min home at the same speed with no problems.

    Then we forgot it happened at all.

    That was the same day we got our oil changed so we made that mini roadtrip. 

    And now there are dark spots all over the driveway and not in just one isolated spot, but 4-6 different spots, and looks like a few different shades and of dark brownish, amber, or possibly they have hints of oranges and reds and all different sized puddles and coming from all over under the hood. i have no idea which fluid (s) these are, even after the smell and feel tests. (Partly because i have no frame of reference on what is what...but also they do all look similar and also different...)
    Any help offered is much appreciated because i currently have no money to bring it to a shop even for a quick diagnostic, if they charge for those....???

    Need haaalp!!
    I cant lose this car right now, i mean it is NOT optional so please advise me what to do here, anyone ? I dont think i can pay mechanics in just kind words and high five emojis, so any helpful tips are welcome...and needed!
     Thanks again!
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    Well it's an old car and if the drips aren't significant, you can just keep an eye on all the levels and add fluids as needed.

    You might spread newspaper out, drive on it and then "read" the papers in the morning. The colors should be distinct on white newspaper and you can tell where the leak dripped from by it's position on the paper relative to the length of your car.

    Maybe you could borrow a set of ramps and scrunch under there and tighten up a few things?
  • kyfdxkyfdx Moderator Posts: 191,385

    How often should i change my oil on an 03 honda civic lx that just hit 186,080 miles and is about to be driven at least 80 miles per day due to commuting for new job? Should i be expecting some issues no matter what? Already have a few unsettling cues popping up but i dont know anything about cars and could easily be mistaking nothing for something. Dont have money for check up at the moment so need all the helpful tips i can get until im able to have it professionally examined again... please and thanks to any info/opinions offered on this specific car and situation 

    Pretty sure you have a 7500 service interval for oil changes. Just make sure you use the proper oil weight and viscosity for your car.

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  • robe48robe48 FLMember Posts: 2
    I see all the posts about overheating and I have experienced the same thing for 5 years. My car overheats and looses antifreeze. I have 370K miles and make sure I top off the antifreeze before long trips. I can drive 600+ miles at 70 with no issues unless I slow down due to traffic or get off the highway. I have had the radiator replaced, the radiator cap twice and thermostat twice. Had it pressure tested and just recently had it tested for a head gasket leak, but mechanic said there was no issue. No leaks when sitting. Seems to leak while driving as I can smell the antifreeze. Tried head gasket sealer and radiator sealer. The radiator sealer ended up getting sprayed all over the overflow reservoir. Any ideas as it seems I have tried everything. The car runs just like it did when I bought it. Great pickup, great mileage. Four different mechanics have looked at it and can't seem to figure it out.
  • robe48robe48 FLMember Posts: 2
    Forgot to say that I have a 2004 Honda Civic EX
  • HondacrewHondacrew Member Posts: 1
    I wanna keep this simple and cut to the chase. I got a 2004 Honda Civic with 220,000 miles n running . The only thing now is she getting older ,I got to keep adding coolant to her when going from A to B. i loose coolant everytime I go drive . I drive from LA to Vegas which is ballsy with a car that looses coolant and I still make it because it's topped off. But stopped to off coolant when it cooled down for hour while having lunch on the way to Vegas. Cya, don't ever open radiator cap when the engine is been driven for a long periods . Wait till the engine is cool. Don't suggest long trips when a car is loosing coolant. But I choose my battles. I've replaced the rad cap, radiator , thermostat, upper, and lower hoses. Still loses coolant. The only leak I see when Poppin the hood is the coolant reservoir is splashed and there's coolant drops on the radiator fan . The mystery leak. My next step is to replace or at least take a look at the water pump if it's leaking. Maybe even replace the radiator coolant reservoir and rad cap again. Will update as soon as I do it but for now just topping her off as usual going from A to B. My Honda Civic is on senior citizen status. Just keeps ticking but needs a little TLC as she is older now.
  • JakeM18JakeM18 Member Posts: 1
    Okay, so I figured out everyones problem with the disappearing coolant in a 2000-05 Honda Civics. There are 2 gaskets for the thermostat, one for the actual thermostat and one that sits between the housing and engine. The only way to detect the leak is to pressure test It only after the car has run for 15 to 30 minutes. To spot the leak, remove air box and look where the thermostat housing meets the engine and you will see where the wet spot is. The Gasket you need is a funky horseshoe shape. Price for one ranges between $8 to $20. One last thing, this gasket going bad is uncommon, most mechanics change just the head gasket and not the other one.
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