Cooling System Problem! Need Top Up Coolent In Radiator Everytime

[Nosure]

the problem: less coolent in radiator after drive,I need top up everytime when engine is cool(about 250ml sometime more sometime less). the coolent in overflow bottle is getting more and more. so thats mean: coolent flow to overflow bottle when hot, but when cool down the coolent not fully go back to radiator. i did some record. the coolent still go in to radiator when cold but not as much as the coolent from radiator to overflow bottle when hot. say coolent from radiator to overflow bottle 500ml when hot, when its cool down the coolent only come back to radiator 250ml.

I went to a few place to check the cooling system. all good. no problem at all. all of them suggest me try to change a cap.

then I bought a new radiator cap(1.3bar), nothing changed.

but my car never overheat always 75-85degree on PFC. can i just drive like this? don't need really care about it??? I worried the coolent in radiator will getting less and less during time.

I got arc radiator and nismo cap.

car is r34gtr.

anyone help please!!!

[Simon-S14]

pressure test the radiator, that will tell you if there is a slow leak or not.

[Nosure]

pressure test the radiator, that will tell you if there is a slow leak or not.

already done the test. no problem at all.

[mad082]

the fact that if isn't drawing coolant back into the radiator suggests there is something wrong. if you have a new cap, then i would be looking at the overflow bottle or the hose to the overflow bottle. there may be a small amount of debris at the bottom of the overflow bottle that is allowing the coolant to come in, but when it tries to suck it back in it is blocking up the hole and not letting it back in.

[simpletool]

If it's not the cap then it is likely the tube running form radiator overflow or quite possibly the nipple on the radiator. My thoughts are that the force of fluid coming out of the radiator when hot is high but the force under vacuum for refilling when cold is low. The hole might have corroded or the hose is partially blocked.

The hole in my aluminium radiator was blocked from a little bit of crap, I just scraped it out with a drill bit.

[EFI Performance]

First thing to do is to look for coolant stain's over your engine block, top of gearbox at rear, around hoses ect, my next thing would be respective of head gasket or turbo seals.

[Nosure]

thanks guys, i will try to clean the hose and the hole.

[Nosure]

already clean the overflow bottle. just wait for cooling down hope this help.

[Nosure]

just checked. its getting better, but still about 100ml coolent less in radiator. maybe some air in system??? but the conlent in overflow bottle is same level as before driving.

[Nosure]

its still about 150ml coolent less in radiator. the coolent should be full in radiator no matter engine burn water or not is that right?? if the engine burn water the coolent in overflow bottle should getting lower not the coolent in radiator?

PS: I have nismo water pump

Edited November 1, 2009 by Nosure

[Simon-S14]

if the motor is using coolant it will use it from the radiator first then the overflow.

either you have a small leak which is only evident under pressure or you have a headgasket issue.

[Nosure]

if the motor is using coolant it will use it from the radiator first then the overflow.

either you have a small leak which is only evident under pressure or you have a headgasket issue.

even the engine using some coolant does the radiator should still full? and the overflow should get less coolant?

[Simon-S14]

the radiator should always be full. The overflow bottle is an expansion chamber basically when the coolant is hot, it expands and some is pushed to the overflow bottle and then taken back into the radiator once cool.

what you need to do, is fill the rad with bleed screw on the manifold taken out til the system is full. then reseal the system, make sure the overflow bottle is filled to the MAX line and then mark it.

drive for a few days and then re check it.

if you have lost coolant from either the rad or the overflow then you either have a leak or a gasket problem, simple as that

[Dorigecko]

better way to bleed system. leave your cap and cock on the top of your manifold off, run the car up to op temp and let all air in the system bleed out thoroughly.

making sure your overflow is half full?

[Nosure]

the radiator should always be full. The overflow bottle is an expansion chamber basically when the coolant is hot, it expands and some is pushed to the overflow bottle and then taken back into the radiator once cool.

what you need to do, is fill the rad with bleed screw on the manifold taken out til the system is full. then reseal the system, make sure the overflow bottle is filled to the MAX line and then mark it.

drive for a few days and then re check it.

if you have lost coolant from either the rad or the overflow then you either have a leak or a gasket problem, simple as that

thanks mate but where is the bleed screw?? and how can I do it?? some more detail please

[Nosure]

better way to bleed system. leave your cap and cock on the top of your manifold off, run the car up to op temp and let all air in the system bleed out thoroughly.

making sure your overflow is half full?

OK I will try it. thanks mate

[Nosure]

will a arc air removal tank able to fix this problem?? anyone know?

[Simon-S14]

no

[Mr. Untouchable]

dont rule out heater core!

[Nosure]

whats that mean?