My brother has a 95 GS and the water that is in the engine keeps being thrown into the reserve water tank after driving. So everyday he uses it he has to pour water into the water tank, and if youlook at the reserve tank its full of water. It has a new radiator and a newthermostat. I dont know whatcould be cuasing this.

 

Clogged line?

 

you probably just have to much in there.... if it fills up every time you turn the car off than it's probably just full. so every time you fill it backit's just poring that extra out b/c it's got all it needs. is it running hot at all? if itIS running hot and this keep happening than you may have a problem, mine did this when my head gasket was blown (these cars are nitorious for blwoing HG's)btw.... it costs mabey 3 or 4 for actual antifreeze and that is what you should be putting in there. you can damage your car if you are only putting water in there...

 

The car never over heats or nothing like that. I always make sure that the car is running 50/50. Whats funny is this car has almost everything brand new..... Last year the water pump went out so the whole engine had to be rebuild. New gaskets, tranny, clutch, valves, pcv valve, cooling sensor (not sure whats the exact name), EGR Valve,alotmore. What Im thinking maybe there is a leak somewhere when driving, I heard its possible. Thanks guys for the replies.

 

again, you say that the overflow bottle is full every time but are you sure that it's not just full? have you driven it with the water still in the overflow bottle and not put anymore in?

 

Try a new radiator cap first,
and also check for a blown head gasket.

 

thats the first thing that came to mind also except that he said that he just changed all the gaskets (assuming that includes HG) lsat year.

 

Was the system ever correctly purged of air bubbles, first and foremost?
While cold, remove the radiator cap and watch the flow. If the system WAS full, even cold, it would start to overflow shortly after, if not as soon as, you started the car with the cap off.
If it has a weak stream, then starts to overflow after the motor has warmed up, then you've got air pockets in the system. That means that the system wasn't correctly purged. This is a really easy and really quick way to check.
If the system passes the purge, then follow the rest of the things stated above with the radiator cap first.

 

When you change a radiator or change fluid your suppost to get a new cap. So it came with the radiator, I dont like it its one of those presure caps. One more thing now that you mentioned bubbles. Sometimes when warming up the car if you look at the reserve tank, you can see little bubbles.Im goin to Mitsubishi Today and getting a new cap.When the car was at the shop the headgasket was also changed.Today I had to add about2 cups of waterwith antifreeze becuase I didnt add any in the past2 days.It never did this before, thats why I bought all the new parts.

 

Sounds to me like you need to also purge your system of air. When you say pressure cap do you mean one of those that have a tab on the top that you press down to seal it and pull up to release it?