anti freeze leak

i have 98 tacoma 209,000 miles uses about 1 cup antifeeze/ tank of gas i have replace radiator, water pump/thermostat have heater core by passed new radiator and heater hoses pressure test shows very slight loss combustion gas test at radiator has been done 3 times shows good cant see any places antifreeze is leaking the only other thing i can think of is metal bypass line and small hose to manifold, and hoses to oil cooler oil is clean and antifreeze looks good any ideas would be appreciated thanks

 

Headgasket

 

Pressure test the system.

 

He did do a pressure test. The lack of punctuation makes it hard to read.

OP, did you replace the radiator cap? It could be slowly evaporating.

 

From a similar personal experience this would be my guess as well

 

You might get underneath by the passenger side, where the front O2 sensor is located, and look up towards the front of the transmission, and see if you can see any coolant dribbles. Or get a long mirror extension and look behind the motor from the top. Theres a filler plate back there that coolant could be coming out of from it pooling up in the valley in there. Possibly from the heater bypass tube or freeze plug. Read through this thread. Pics are all gone, but may be your issue. Which is what mine is. Doesn't leak onto ground and you wouldn't see it otherwise. It happens when the truck sits, or overnight. When it runs it expands and doesn't really leak.

Edit. There's a couple pics on page 2

 

sorry about punctuation i have replaced radiator cap. pressure test shows only very slight drop ,my tester is old maybe leaking itself, tried yesterday with motor running could not see any vapor from oil cap or tailpipe. turuck has been losing a small amount of antifreeze for a couple of years, has never been hot, no vapor or smell at tailpipe, oil is perfectly clean, oil cap is clean,i had an 89 that headgasket went out on this doesnt act the same nightprowler i will lock at back of motor thanks, i have also tried to check hoses to intake cant see any leak there either thanks for all the help i would hate to tear down and find it was something else 89 blew between #2 and #3 was very obvious this truck really run good but i will do a compression test and get back thanks again steve

 

sorry 2.7 four cylinder