Hi, I'm a bit worried because AFTER A FLUSH my coolant level inside the radiator seems to be lower than my usual neck level. It's not super low, I can still see the coolant juuust above the rad fins, but it won't go lower than that and the rad won't get empty. It doesn't leak because everytime I top the radiator off the same exact amount of coolant goes to the reservoir. This happens after a drive and also when cold. I top up top up top up top up till overspill...no joy. THE SYSTEM SEEMS TO BE MAINTAINING TO THE NEW LOWER LEVEL. I see no rise in temp, milky substance, oil in water, white smoke or anything. A bit sweety smell of the burning coolant due to a small overspill which I think is fine after a flush. I did the usual flush proceedures, drain & fill, burp the system, top up etc. I replaced the red toyota coolant + tap water combo with Mitsu longlife green + distilled water. I have a feeling the rad cap is on its way to heaven. Anyone please...anything...boiling point, HG idk...

 

The radiator should always be full. There is no new level. Something is wrong.

So, slap on a new radiator cap.

Coolant expands with heat and gets pushed over to the jug as the engine warms. As the engine cools this coolant gets pulled back into the radiator.

Check that the hose going to the jug is not cracked and all connections are a tight fit. If loose the radiator will just suck air when it tries to pull back the coolant that got pushed over to the jug when the engine was hot.

 

^Thats what i would do, but if it all looks good try this:

Let your car warm up to normal operating temps, then shut it off and pop the hood. Check to see if the upper radiator hose begins to collapse. If It does AT ALL I would replace the radiator cap. This would show that the cap is allowing the antifreeze to overflow into the bottle but then not allow it to return as the fluids/engine cool down. This happened to my Evo at only 55k.

Similar thing happens when you put a bottle of warm water in the fridge with the cap on.

 

Your replies are really helpful barneyb and boostedmkiii, I now have a clear picture of the system.

I will do as suggested, and come back for an update.

 

Did what you guys told me. New rad cap in, a few top ups and burps, and its been fine since...hopefully it stays that way. Also replaced the rubber black hose inside the reservoir which was found to be loosed. Thank you again!

 

Years ago I was driving a '78 Trans Am (BTW, a great car). Anyway, I had the same problem as your car had, jug full and radiator low. I pulled the cap off of the jug (I always write jug because I can't spell reservoir) and underneath was a white plastic tube that had become so loose I could spin it with my fingers.

As for the cap, it is a good idea to replace it when you change coolant, which according to the service manual should be every thirty thousand miles. That is about all you can get out of a pressure cap, the spring gets weak or the gaskets leak.

 

Yes exactly mine was about to pop off anytime. I always thought whatever inside that plastic container (I always have trouble spelling reservoir too because it sounds french plus I'm not a native english speaker) was fine until you reminded me.

The cap looked like its never been changed and was really rusty underneath. I got another one off evo6 (same 1.1 bar on yellow sticker) which seems to be fine.

 

Awesome! Glad you got it all figured out. It always sucks having a car that is a blast to drive, yet you can't due to an annoying/minor issue... Trust me I know the feeling

Yeah, I have had some last 40k, and some last 100+k....

 

It is annoying! I hate owning an evo because it entitles me to worry a lot..haha

You guys are great...give me a shout if you happen to be in Malaysia for holiday in the future!