Lately, I find that my 2.5 TL is always low on engine oil. After an oil change I check the oil level on dip stick and than after a 1k or 2k miles of driving, the dip stick barely register oil.
Does it mean the head gasket is going out? Will it help if I change oil frequently?

could be your valve seals,

Most likely would be your valve seals. Kind of a pain to get replaced, though... If it's burning THAT much, I'd think you'd notice the clouds of blue smoke coming out of your exhaust...

~Cheers~

yea most likely your valve seal might need to change them asap had a similar problem with my car had to put it in the garage for like 2 weeks but it shood only take about 3 days work to get it fixed.

Is this a DIY, I am pretty handy and do regular maintenances on all my cars. But never did a valve job.
A little guidence on right direction and I can do it.
any help is appreciated.

Would you be able to pull the head to get to them? I had asked one of my friend's shops and even they were kinda wary on doing it. Not that they couldn't do it, but it'd just take up too much of their time.

~Cheers~

ok, that brings to this next question: is it called valve adjustment? How much would the dealer charge?

It's not a valve adjustment, as that means they probably just re-seat the valves. This would involve that plus actually replacing the seals which means, that + more $$.

~Cheers~

How many miles on your 2.5TL? Has it had regular maintenance?

Ever changed the PCV? PCV hose blockage can force oil/crankcase gas into the intake duct and use lots of oil. Intake duct will be coated w/ oil and throttle body will be filthy w/ oil and grime. Fix is simple, clean/replace PCV and PCV hoses.

Have you checked for leaks. It doesn't take a huge leak to loose 1/qt per 1000 miles which would fit w/ your loss rate.

Honda valve stem seals are pretty good. Valve stem seal oil loss typically occurs at idle, where you may notice a steady puff-puff-puff of blue oil smoke, and when you accelerate after an extended idle you will get a small cloud of blue oil smoke.

good luck

it has 214k on it. I am up to date on maintanence. I have changed pcv valve but not the hose. I will do that as you mentioned.
There's never any oil on the ground as I hardly drive the car every day commute, it's parked in the garage and there's no oil on ground. I never noticed blue oil smoke either.
I will have to keep an eye on it.

I would recommend moving up to a 10W30 motor oil assuming you use the recommended 5W30. A high mileage oil would also be good.