Celica VVTI oil leak

So I got rid of the Merc and got myself an old VVTI Celica. Other than the power steering not working - something that doesn't bother me - there is a leak somewhere. I've put 4.5 litres in and after about 500 miles it's all gone! Can't see any visible leaks in the engine that would should that much loss. I've had a look around and seen Wynns Engine seal stuff. I know some people frown upon it but do you think it's worth a blast? Can't get any worse than it is. I need to change the head gasket at some point in the future but for less than a tenner it's gotta be worth a go until I can put the time aside to do the big job :)

thats a lot of oil in 500 miles , could it be burning it ?
and i would hold fire with engine sealant , what millage is it ?

I had an Avensis with the same 2.0 vvti engine and that also had a mysterious oil leak. I seem to recall the 1.8 vvti in the Avensis also had oil issues but it's been a long time since I've had to browse Toyota forums.
I used to put around a litre of oil in per 500 miles.
No visible leaks, no blue smoke, emissions were fine, I just lived with it.
4.5 over 500 miles is a bit excessive though. At least you won't have to worry about changing the oil though!

4.5L in 500miles is a hell of a lot. Either its leaking or it's getting burnt.

First thing need to get it to a garage so it can be inspected from underneath.

If not leaking out of the engine, then it's leaking in the engine (e.g. worn piston rings, faulty breather system) and with it leaking that badly I would expect a lot of blue/black smoke if it was leaking internally.

It should be really smoky in the morning when its cooled down if its burning oil . if there is no pool of oil where you park the car then it must be burning it . but 1ltr every 100 miles nearly .
are you sure your not putting it in fuel tank .

Normally for burning oil, It is the rings and or the valve stem guides /oil seals (in high mile engines) . TBH if it was burning that amount of oil then the exhaust would be like a smoke screen from wakey races

have you checked if any oil in the cooling system?
i have just used some Hyper Seal Engine Revive Blown Head Gasket Cylinder Block Engine Sealant Repair
on my 2006 sxi after it started leekin water into the oil a small head gasket fail, fixed with no problems,
i was a bit worried about using it but after phoned 3 repair centers they all said the same, we would use a cooler repair kit. rather than new head gasket, 99% & permanent repair but wanted £100 to do it. I did it all for about £40
i had oil in the water and water in the oil with gunk all over filler cap, car ran great with no smoke or loss of power but it was a pain because i didnt dare drive out of town in case it went completely
used repair my self then removed head cover tho remove all the gunk on top of cams, used engine flush then full oil filter & oil change & BLOW ME works perfect.
no more loss of oil or water & been out of town a few times with no issues.

Quick follow up on this. I've had a good look at the engine (as good as I can with a four year old running havoc) and two things came up.

1. Acceleration is piss poor and goes in fits and bursts (when warm) - After disconnecting both O2 sensors it turns out that's related either to a knackered O2 sensor or the cat is b0rked. Either way i'm not too bothered right now
2. Oil consumption is ridiculous but there is a very well known issue with the engine in my Celica where the piston rings get "stuck" with carbon build up due to a manufacturing flaw allowing oil to seep into the combustion chamber. This of course would cause the oil to burn off through the system.

Now #2 above lends itself well to cause #1 but I'm not confident enough to replace the piston rings myself as Ive never done it before although apparantly you don't have to remove the engine to do it.

Anyone got any tricks on releasing piston rings without disassembing the top of the engine and part of the bottom? I've just poured half a can of Wynns Engine Flush into my oil to see if it helps. Getting plenty of smoke which I'm hoping is the carbon deposits burning off but from what I read it's a hit and miss affair on whether it fixes it or not and I will see lots of smoke for a little while either way...