1988 Toyota Pickup waater leak

  • 2.0L
  • 4 CYL
  • 2WD
  • 131,000 MILES
I loose about 1 gallon of water every 30 to 40 miles. There is no steaming, no miss, and no visible leak. Took the thermostat out in the pretence of checking the water pump. 2 back surgeries and a hip replacement have prevented that so far. Raced the engine up with thermostat in after it had opened up with radiator cap off and no water movement. Hence the removing the thermostat. It requires a 6 lb radiator cap, so I got a 14 and put on it and water was coming out the exhaust. New radiator, engine has been flushed about 12 times but still losing water. It has a performance cam ( high end ) but at 55 that shouldn[t make a difference. Hope you can help me with this because at this point I am sort of lost. I say sort of because I have been working on one kind of car or another since I was 14. Now at 64 things have gotten harder to do. Thank you in advance because I know you have the answer, robert
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Monday, June 8th, 2015 AT 10:45 PM

1 Reply

You already found the major clue. How can coolant come out the tail pipe?

All of these are typical symptoms of a leaking cylinder head gasket. When combustion gases get pushed into the cooling system, that can pool under the thermostat and prevent it from opening. Thermostats have to be hit with hot liquid to open. Hot air won't do it.

Next, most cooling systems use a 15 pound radiator cap because the higher pressure makes the water in the coolant boil at a much higher temperature. If yours actually does call for a six pound cap, doubling that increases the maximum pressure that can be reached, and that is going to push coolant into the cylinder even harder and make the problem worse.

There's two tests you can do to verify a leaking head gasket. One is to add a small bottle of dark purple dye to the coolant, then check later with a black light. The dye will show up as a bright yellow stain that you can follow back to the source. If the head gasket is leaking, you'll find the dye inside the tail pipe.

The second test involves drawing air from the radiator, while the engine is running, through a glass cylinder with two chambers partially-filled with a special dark blue liquid. If combustion gases are present, the liquid will turn bright yellow. It's usually less expensive to have your mechanic perform that test. You can borrow that tester from an auto parts store that borrows or rents tools, but they make you buy your own bottle of fluid. That's because it will be rendered inactive if it is allowed to freeze or if it gets contaminated with antifreeze. It's easy to suck up antifreeze if you aren't careful, and since they don't want to risk borrowing you this tool with contaminated fluid, they made the last person buy their own too.
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Monday, June 8th, 2015 AT 11:12 PM

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