Question about 1999 Honda Civic

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Is a compression test a conclusive way to check for a leaking head gasket? My 99 honda civic (D16Y7) Is losing coolant and ruining radiator caps from the coolant obviously getting too hot. I did a compression test on each cylinder, as well as a pressure test with each cylinder TDC with 180psi for approximately 1 minute with the engine at running temp. At the same time i had a cooling system pressure tester on with 25psi...there was no loss of pressure in any of the cylenders or cooling system, but it continues to loose antifreeze and ruin radiator cap seals, there are no visible leaks in the engine bay...Im am more than confused at this point...

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Check for milky oil
It may help to have the radiator cleaned and flushed, and a new thermostat installed, the coolant may be going out the overflow
Not certain how it ruins radiator caps, they hold about 5psi in the radiatior and let excess pressure into the overflow, then when the engine cools, allow coolant to s uck back form the overflow tank

Posted on May 27, 2011

  • claytonhough May 27, 2011

    i just put a brand new thermostat and fan switch in and i have a new rad cap but after the last three that are now garbage im not so sure i want to put another new one on it and the waterpump isn't the problem



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My Granddaughter has a 2003 Honda Civic which has started overheating and the coolant will be low. Can see no leaks. Happens after 2-3 weeks of driving. A mechanic pressure tested the system and it...

Hi, its not good news im afraid by you describing that with the coolant cap off and revving the car causes the pressure to build up and push the water back out it sounds to me like the head gasket is on its way out, what you need to do is take it to a garage and dont have a compression test done you need to have a gasses test done, you can buy these yourself if you want to and what it does is this.

its a plastic tube with blue liquid inside it then you take the coolant cap off and place this in its place you then run the engine and rev it up then you squeeze the rubber at the end of the tube and it then sucks the air out of the coolant and through this liquid then if it detects gasses from the engine in the coolant then this turns the liquid green and this is then telling you that the head gasket needs changing.

please dont let it keep over heating as this will cause the cylinder head to warp and you would then need to get it skimmed to make sure its not warped, get the gasses test done as a compression test dont give you a true reading as the engine is not running when they do a compression test.

let me know how you get on or if you need further assistance ok

plz rate this solution as i have a whole page of unrated posts, thanks

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You may have a small pin hole in one of your hoses that is only leaking under pressure. Of course you may not notce it with the vehicle idling because the pressure is higher as the rpms rise while you are driving.

More importantly though, you need to check your oil dipstick. If the oil looks "milky" you may have water leaking into your oil. This can happen if you have a problem with your "heads" such as a small crack. A cracked head can lead to a blown motor so check it out as you are checking all of your hoses on your cooling systems.

Good Luck!

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