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2002 1.7l rad consumes about 2-4 ounces of fluid per day/100k. Pressure test holds for 30min np, CO test for combustion gas also negative. No visible coolant leaks, no oil in rad overflow, no sweet exhaust smell, but the rad consistently keeps going down every day after running about 100k to work and back. Rad overflow has fluid. I suspect the head gasket but I'm not convinced. Civic has 160k and runs fine!
Looking for next diagnostic ideas?
Thanks

 
Rep Power: 210

does the level in the overflow bottle continue to go up? as the rad level goes down? if so = blown head gasket

 
Rep Power: 142

How does your oil look, check the dip stick and valve cover cap to see if it looks discolored by radiator fluid possibly?

 
Rep Power: 518

The usual 1.7 head gasket failure won't ever have those symptoms.
They will usually pass every last one of the common tests and inspections most people would try.

 
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Oil looks fine. I change it regularly every 5k-km and it always looks dirty but no water, no white etc.

 
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I have a second 2002 Civic, head gasket went at 258k. Symptoms were easy as the rad overflow was oily! This one is stranger! Just keeps drinking rad fluid. It must be going somewhere?

 
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Yes, the rad overflow is full but not overflowing. Cap is on tight. Maybe I should lower it and watch? Just keeps drinking rad fluid every day!

 
Rep Power: 210

it is not drinking it, its leaking out the top of the bottle

the overflow bottle is probably literally overflowing while you are driving, thats where the coolant is going, this is a sure sign of a blown head gasket,

 
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Thanks mikey1. Two questions 1) is there any other definitive test to test for a blown head gasket before I spend the money to get it fixed?
2) Should it not be sucking the fluid back into the rad from the overflow when the rad is down.
Thanks... Terry W.

 
Rep Power: 210

wait for ezone to reply, or pm him, he can explain how to test it better then i can, you basically need to apply air pressure into the cylinders through the spark plug holes and see if bubbles appear at the radiator cap/filling tube,

but from what you are describing i would say with 99.9% certainty you have a blown head gasket

 
Rep Power: 518

The basic procedure is in this post, and read the entire thread because there's info all over it.

https://www.civicforums.com/forums/36-mechanical-problems-vehicle-issues-fix-forum/356966-radiatr-2001-ex-coupe.html#post4649516


And like I said in that other thread today:

If someone wants to sponsor me a go-pro or something, I'd gladly make a video of the entire test. I'll need a test subject with a suspected blown head gasket too. Must be local and able to drive to my shop.