This is a tale that goes back about a year when I found my very first car. I needed it to commute back and forth to school. When I bought the car it worked great, everything I could have wanted.

However, that soon changed when it began overheating, and to be specific it is a 2003 honda civic ex, automatic. I took it back to them after having to pay towing expenses. They said they didn't know it had issues (bull) they said it was due to a radiator, so they installed a new one.

When I got it back it drove fine then it began exhibiting the same symptoms soon after. I decided since I loved the car I wouldn't even bother with the people I bought it from, big mistake and I should have just returned it...I didn't because I was sick of looking for a car and school was about to start. This began the routine of having to fill it with antifreeze everyday before and after class, if I didn't it would most certainly overheat and then I'd have to blow hot air all day. So I took it to another mechanic who figured it must be something wrong with the cooling system and said the fan was acting slow, so he replaced the fan-switch and thermostat and said that it wasn't the water pump. I was hoping this would do it, but it did not.

He then tested the head-gasket twice and it came back negative. Then they tested the catalytic converter, came back negative. This mechanic, then proceeds to tell me the people who sold it to me may have put a sealant in which gummed up the engine and is clogging things so it can't function correctly, or put on the head-gasket wrong or any number of things to the engine. Although, wouldn't this still make the head-gasket test fail?

He tells me I may need a new engine because to figure out if it truly is an engine problem that would cost as much as a new engine. I don't know what to do or where to go I am at a loss here. Spending my money just to have mechanics tell me there is some mysterious "undiagnosable" problem with my car is the most frustrating thing ever. No one can fix this car it seems. PLEASE I beg anyone who knows how to figure this mysterious problem out!

Any help would be greatly appreciated.

Thank you

7 Answers 7


If you are losing coolant (you say you have to add coolant daily), then there are only two places it can go. Either on the ground or in the engine. Check your oil to see if it's a milky color. If it is, then the oil and coolant are mixing and you will need the engine rebuilt. If not, then you probably won't need to replace the engine.

Next, does the exhaust smell sweet? Is it extremely humid when exiting the exhaust tip? Is there any white smoke from the exhaust? If so, the coolant is leaking into the combustion chamber, and being burned off. This indicates a problem with the head gasket.

Is there any coolant on the ground? You should be able to pretty easily determine where it's leaking, if there is such a leak. Check the passenger floor to see if it's very wet. Is the air very humid when you have the defrost on hot to help with cooling? If either of those is true, the heater core would be the area to look at repairing.

  • Be careful with any conclusions with water coming out of the exhaust, the cat will produce a great amount of steam/water which can condense on a cold rear silencer. Commented Sep 13, 2014 at 15:56
  • Yes, but if it's burning coolant it will have a distinct smell as well. And condensation isn't moisture to produce white colored smoke. It will only result in steam on colder days, under normal conditions.
    – dobey
    Commented Sep 13, 2014 at 20:17
  • No, i've looked at all the symptoms for a blown head gasket already. No milky dipstick and no white smoke. Also no leak, I got a pressure test done already and it came back negative.
    – AppleFix88
    Commented Sep 13, 2014 at 22:20
  • Well you can't be having to add coolant on a daily basis, and also not have a leak. It has to be going somewhere, if you need to add more.
    – dobey
    Commented Sep 14, 2014 at 2:51
  • 1
    Coolant doesn't just get used up like that. It could be boiling off, and overfilling the overflow tank, but that would leave a noticeable pool of coolant on the ground, and coming out of the tank. Boiling point of 50/50 mix distilled water and ethylene glycol antifreeze is about 265F. If you're letting the engine get that hot, you're way past the point of overheating, and possibly causing further damage to the engine.
    – dobey
    Commented Sep 14, 2014 at 13:00

Total agreement with dobey. Coolant doesn't just disappear. It either goes on the ground (external leak), in the passenger floorboard (heater core), in the engine oil (head gasket), gets burned up (head gasket, or possibly intake gasket), boils off, or it stays put. I won't address any of the stuff that you've done, but I will add:

1: compression test your cylinders. If you have one that is much lower than the rest, you need a head gasket. You can "borrow" these for free at AutoZone, or similar parts stores. A bad head gasket can let water in the engine to be burned, but also pump compression into the cooling system.

2: does your coolant have brown gunk in it? This is a sign that a sealant was used, and could be making the problem harder to diagnose. A gunked-up thermostat could let the engine overheat, and boil the coolant out through the radiator cap.

3: Steam from the exhaust is normal, but only while the engine is warming up. If your car has been running for 30 minutes, there shouldn't be any steam coming out of the tailpipe.

4: Some cars have very specific bleeding procedures to remove all the air from the cooling system. If your car has a bleed procedure, you need to follow it exactly.

5: is there any steam coming from the engine compartment? It's possible that there's an external leak on the exhaust that is burning up the coolant before it hits the ground. When your engine is hot, pop the hood and look closely for any steam coming out while the engine is running.

Once again, the coolant is going somewhere. Find out where it's leaking and you will solve your problem

  • It must be the head-gasket which I figured but was hoping it wasn't since it is the most expensive thing as far as overheating cars go, and it also didn't follow the normal signs of a head gasket (i.e. white smoke or milky dipstick). Like you said THE COOLANT MUST BE GOING SOMEWHERE and it's not on the passenger floorboard or the ground so it's being eaten up somewhere in the engine (head gasket). I will follow your advice on a compression test of the cylinder. Any advice or links on how this is done? that would be great. Thank you for your time/help.
    – AppleFix88
    Commented Sep 15, 2014 at 15:34
  • 1
    It's pretty simple. The tool screws into where your spark plugs go, and you do one cylinder at a time. Make sure you disable the ignition or fuel system by pulling a fuse as you don't want the engine to run, you just want it to crank like you're starting it. Just google "how to compression test" and you should find all the info you need.
    – bwest05dm
    Commented Sep 15, 2014 at 16:14

Try these steps replace cooling temp sensor... install new hoses top and bottom radiator hose along with any other smaller hoses chk if real soft rubbery feeling its time to change if stiff slighty pinchable then they good..second replace radiator per it can be clogged and not allow proper water flow..leave cap off make sure fill with antifreeze and start car allow it to warm up and watch u should be able to see the water flow this will allow the air to come out per air pockets are a big cause...now buy a new radiator cap per this also small but cause a big prob...also while watching the water flow flow if bubbles stay present it could be head gasket this pushes combustion gas thru and can cause antifreeze to dicipate hence why u keep having to put more unless yur pump leaking or hose this the only other way u will get low on anti freeze...hope this helps it took me a while to figure out so i didnt have to spend lots of cash on a mech that wouldnt probably now this either top secrets lol...they wont tell u its all biz...hope this helps


From your question, you have an intermittant fault somewhere on the cooling system. The way forward would be to replace the engines thermostat, making sure the new thermostat is a genuine Honda part. Get on the net if you have too, but make sure it is a genuine Honda part. The next step is an 'Extended Road Test'. The ideal test would be for your mechanic to drive your vehicle, perhaps over a weekend for a good number of miles, and if the fault occurs he would have first hand knowledge of whats going on. He would know exactly what happens as the fault develops. Intermittant faults can be the very hardest of faults to determine.

  • I've discussed that with my mechanic, we are in talks to have him take it over next weekend. I am positive it isn't the thermostat seeing as I've had that replaced twice and found the second one was compatible with Honda. It's something more complex than that.
    – AppleFix88
    Commented Sep 13, 2014 at 22:23
  • A Honda thermostat is a Honda thermostat. They can be quite qwerky Commented Sep 14, 2014 at 14:58
  • I had it replaced and tested it is doing what it is suppose to from as far as everyone that has looked at it can determine.
    – AppleFix88
    Commented Sep 14, 2014 at 22:30

I've had a 94 del sol or civic esi some time back and had all sorts of diagnostics done to no avail. Radiator replacements, coolant tried em all. Eventually it all came down to that dreaded day that i have found a milky dipstick due to a a bad cylinder head gasket. Your case is a an early sign that compression is leaking into your cooling system. Car can function indefinitely but not advised since this can cause problems to your cylinder head. Extreme heating can cause you cylinder head to warp and may need refacing or total replacement depending on the conditions. Top overhaul is highly recommended.


See if it's leaking from the end of a hose, you can cut it and put the clamp back on the remaining end. If it's leaking from the radiator. 40 bucks and 30 minutes of work. If the head gasket is cracked, and you are leaking coolant from the water jackets that go up the motor to cool it, into say oil jackets, or even cyllinders, well, replace your head gasket. If the car hasn't been taken apart in a century it will take a breaker bar, the correct sockets and a good wrench. Breaker bar for the head bolts. You'll need to unbolt the power steering, get it out of the way, take off the timing cover upper and lower, air wrench, air powered wrench I believe for the crankshaft bolt, then follow directions to resetting the timing belt as it is strapped from block to head, head is on top. Could take a couple days. Follow youtube videos and get a reliable ride you'll be fine.


I have worked on a couple of vehicles that had a very fine leak at the seam of the intake manifold. I noticed that The fluids were boiling back into the coolant reservoir. I located the leak on the seem of the intake manifold, I used a dab of "Mr. Muscle" gasket glue (small brown bottle). Worked it into the seem with a toothbrush in tiny circular motions and waited 24 hrs. So far one year passed by and no complaints from the customer.

  • Hmmm I would suspect that a mechanic would have found that already. They told me they inspected the vehicle for any sort of pressure leaks by pressurization the system.
    – AppleFix88
    Commented Jan 10, 2016 at 2:20

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