Anonymous
Anonymous asked in Cars & TransportationMaintenance & Repairs · 6 months ago

My Car keeps overheating!? Why?

My 2002 Honda Civic Keeps Overheating . We put in a new radiator and a new thermostat and it still keeps overheating. Any idea of what it could be?

20 Answers

Relevance
  • Tom
    Lv 7
    6 months ago

    My trouble was the cooling fan did not come on. The mechanic wanted to take the radiator assembly apart----I said no and did some research----I found there was a temperature sensor on the engine---I replaced that for 30 bucks and it worked.

    • Login to reply the answers
  • 6 months ago

    Did you add anti-freeze, to the radiator, or water?

    • Login to reply the answers
  • zipper
    Lv 6
    6 months ago

    There are several reasons this could happen. Bad water pump, head gasket, there is a flow blockage in the block, the cooling fan does not come on " I did a Honda and the fan would not come on, I cawed under the front removed the plug and frond that they had put a plastic spray on the two props, which I had to remove very carefully; plugged it back in and when the engine warmed up the fan now came on." Also believe it or not if the thermostat is put in upside down it will not work. OR there is an air pocket in the heater system which is blocking the flow. Sounds like you need a new mechanic!

    • Login to reply the answers
  • 6 months ago

    Get a mechanic to blow the dickens out of the tiny tubes which could be plugged.

    • Login to reply the answers
  • How do you think about the answers? You can sign in to vote the answer.
  • Anonymous
    6 months ago

    You need some testing. A head gasket is the worst case scenario (or that is cracked head or block first) But there are less dire possibilities. Is the water pump belt there?

    Have someone take off the radiator cap with engine cool, then start it up and let it idle for about five minutes. By now it is warmed up and you should see the coolant rushing by at a rapid rate. Snap the accelerator ( standing away from the radiator. If it jumps up, there is a restriction somewhere. If normal it should flow on through no matter how fast the engine is run. his sight tells you a lot. If it is not rushing by, the water pump is not pumping or there is a major restriction somewhere. Not in the radiator if it is a new one.

    Is the exhaust putting out extreme dense fog? If so, head gasket.

    Next test, borrow a pressure tester from a FLAPS and follow the instructions to pressure test the engine cooling system, cold. A cylinder leak will show up here, as well as any leak elsewhere in the system. I had the head off an engine which--although not overheating--had a thick wax clogging up the head passages. This, despite efforts to flush it out.

    But tests are free and will guide you to the least expensive repair.

    • Login to reply the answers
  • 6 months ago

    Head gasket or cracked cylinder head.

    Time for a new used car.

    Source(s): Mitsubishi Master Tech
    • Login to reply the answers
  • 6 months ago

    It is usually the head gasket leaking compression and combustion gas pressure into the cooling system jacket from the head gasket. If you heat up the engine in the driveway by holding 2K rpm until at operating temperature with the pressure cap removed and it seems fine, then you install the pressure cap and it immediately overheats, the head gasket is leaking. There is also a chemical test but the pressure is coming from the engine head gasket in most cases and the cost of repair may be over what the vehicle is worth. My test (same as GEO mentioned) is simple and will tell you quick if you want to spend $2.5K to repair the engine with a rebuilt head and gasket or dump it for scrap.

    Even if it was the water pump (not likely), the failure caused it to overheat and warp the head = gasket seal failure. The machine shop dohc head rebuild will be about $800+ plus all the extras like gaskets and labor.

    I wouldn't advise using a used head without warranty! You then take the risk that a very pricey bill may X2.

    Get a new head or the OK from a macine shop that your head is serviceable and worthy of the $ fix effort.

    Anyway you can look at it, the car will not be easily fixed if the head gasket is blown from an overheating.

    If you replace the head gasket with the original warped head, it will be a total waste of ($) time and effort.

    The pressure cap is usually about 15 PSI, when you introduce an external pressure force = instant boiling.

    Hot coolant under pressure, then your engine pumps in hot gas pressure over 200 PSI from combustion.

    As the gas leak bubbles accumulate, they overtake the 15 psi pressure cap and it all spews in a boil out.

    • Login to reply the answers
  • 6 months ago

    It's not the radiator or thermostat. What's left to guess about : radiator fans, water pump, head gasket, radiator cap, heater core, freezeplugs, hoses

    • Road warrior
      Lv 4
      6 months agoReport

      Wharped head. Be Systematic--look for external leaks, even interior or car; see if fans coming on. Backflush system. Double check new thermo not froze (New parts Fail) Remove cap, see if bubble on start up. do they Stop? Bubble in system- ?-burp and n bleed.

    • Login to reply the answers
  • 6 months ago

    water pump for sure...also when putting in new coolant in an empty radiator you have to start with 70% coolant and 30% water then afterward you can top off with 50/50 coolant later on if needed.

    • ...Show all comments
    • Road warrior
      Lv 4
      6 months agoReport

      No Not Stupid. Anything can fail, crack in shaft at factory, bad seal, water in bearings. A bad WP can be cause of the overheat, which has now probably progressed to a blown HG and/or wharpedhead.

    • Login to reply the answers
  • 6 months ago

    water pump or head gasket

    • Login to reply the answers
Still have questions? Get your answers by asking now.