I hope ya'll will forgive me, I also don't want to insinuate that you may have a honda but your neighbors might? So here's my problem. Daughter's car, '00 Honda accord, losing coolant and can't find it. Put pressure test on it and after 15 min. or so she's losing pressure. Also put in UV dye but see absolutely no leaks with dye. New cap as well.
Car seems to run good and don't notice any steaming / misting and this type of thing could be generic so thought I'd ask. Engine is V-6 so I'm wondering if cyl. pressure test could tell me anything? I'm thinking it would.

Thanks for your consideration, Daughters love my trucks if that helps. Honda site RARELY comments on threads.

 

A FWIW story, kinda related. My S15 started doing something similar, coolant disappearing and it would run hot on the freeway on hot days.

Pulled all the spark plugs, found a wet one. Hooked the air compressor up to that hole with the radiator cap off, and yep, up came the coolant.

Blown head gasket, could even see it when I pulled it, a water passage near the cylinder failed and the fire ring failed as well so the coolant passed on through.

So it might be a good start to pull the plugs.

 

Thanks Chevy eater I'll try that. The car is in pretty good shape and easy on gas soI'll try to keep it up.

 

I didn't mention the obvious, you may have checked it already, but if not feel around the carpet on the passenger side. If it's damp heater core is bad.

 

I was thinking the same thing. Po should look for sweet smell in the cab when heater is on. And/or antifreeze build up on inside of windshield.

 

I'd put it up on ramps and keep pumping up the pressure tester when it bleeds off. Put some clean cardboard under it and it should show itself. I've never seen a Honda heater core leak. Radiator leaks can be tough to spot. They usually leak at the seamwhere the plastic tank mounts to th aluminium core.

 

Thanks guys, I got busy yesterday and did not try the compression test or adding air into cyl. yet. There is no noticeable smell in cabin or wetness in floor. not sure about windshield film, will ask. Thanks again.