With you loosing that much coolant it should show up soon. I wouldn't add the stop leak just yet until you are sure of what your problem is.
A minor leak is hard to find on the 5MGE's I know as I've had several including all that I've listed below: (Get out your best flashlight and inspection mirror and really take some time going over everything very carefully)
-There is a hidden hose that runs under the intake manifold going under and behind the t-state housing back toward the firewall. You may have to remove the distributor to get a good look at the end connection.
- The lower radiator hose connection at the water pump is up under the power steering pump.
- The metal pipe connection up under the exhaust side head. This is up above the lower radiator hose mentioned above. It is almost impossible to see from above even with a mirror and light. Easier to see if you remove the oil filter and look up from below.
- Heater core could be suspect. A leaking heater core will probably never show up at the evaporator drain hose on this model as some mentioned. (It will leak on the carpet on passanger side of the transm. hump)
- Check the hose going from the back top of the head (near the #6 spark plug) over to the heater control valve.
- A small weeping from the water pump will catch and accumulate on the engine undercover making detection harder to find as it may blow away during driving speed and never show on the pavement.
- I wouldn't advance timing any more than 14 or 15 degrees BTDC. (I'd start at 12 and make sure to short the electrical connection before checking)
Again don't dump in stop leak products yet if you haven't already done so. It would be a good time to do a used oil analysis to see if coolant shows up in the oil sample.
Have you or ANY passengers noticed any different smells lately? My kids complained for over a month before I found my heater core leaking. I dismissed their comments far too easily.
Keep us posted on what you find if anything.
Although the head gasket could be leaking it is much more common on the 7MGE engines.
[ December 07, 2003, 01:23 PM: Message edited by: Cressida ]