Hello All, Strange problem going on, now and then in no particular interval my zed decides to dump aload of coolant, this is coming from the front left where the expansion tank is. The level in the coolant tank reads way above the "H" mark in fact its almost full???? The car never overheats, temp always good, no H.G. issues. I cant understand it, is it just a case of the tank being overfilled?? ive never had to touch the cooling system before, but like i said the car does it when it pleases but doesnt overheat. Any ideas will be appreciated

Mine did this when I first had her. It was a hot day and I had been for a good drive. I understand this is an expansion tank with no return. I checked all the levels again and didn't have further problems.

have you used the aircon? pretty sure the aircon vents out of the front LHS so itcould just be moisture being dumped out of the aircon if its been used for a long time. (i think)

Hello All, Strange problem going on, now and then in no particular interval my zed decides to dump aload of coolant, this is coming from the front left where the expansion tank is. The level in the coolant tank reads way above the "H" mark in fact its almost full???? The car never overheats, temp always good, no H.G. issues. I cant understand it, is it just a case of the tank being overfilled?? ive never had to touch the cooling system before, but like i said the car does it when it pleases but doesnt overheat. Any ideas will be appreciated

 

Fill and bleed your radiator, then make sure that the expansion level's on minimum when cold... if your expansion tank's "almost full" there's no room to allow for expansion!!

 

And if you've never touched your coolantt, I'd drain it and flush - you'll be amazed at the crap that comes out!!

 

Rich

this is a reservoir tank not expansion tank think of it as an overflow, when you over fill your radiator the system dumps coolant into the reservoir for safe keeping, and when you rad gets to low on water it sucks it back from the reservoir, if this reservoir is dumping water dont worry about it may be drain out some of the water in there but i would just leave it

this is a reservoir tank not expansion tank think of it as an overflow, when you over fill your radiator the system dumps coolant into the reservoir for safe keeping, and when you rad gets to low on water it sucks it back from the reservoir, if this reservoir is dumping water dont worry about it may be drain out some of the water in there but i would just leave it

 

Oh right, does the water/ coolant in a zx not expand then? Guess Mr Nissan just put the marks on it for laughs then :headvswal :headvswal

if it keeps blowing out could be your rad cap is on its way out...get a new one if you've only just got the car...could be donkey's years old anyway....big peace of mind for very little money :D

Oh right, does the water/ coolant in a zx not expand then? Guess Mr Nissan just put the marks on it for laughs then :headvswal :headvswal

 

yes the cooling system does expand but that is all done in the rad those marks are to let you no when the overflow is full or empty you should keep a certain amount off coolant in there incase you coolant levels drop within the rad ( the pressure from the drop will suck coolant out of the reservoir back into the coolant system) and vis versa when there is too much coolant in the coolant system it dumps it into the reservoir

:duffer:

Sorry, but you are complettely wrong! C = cold... i,e, cold fluid, minimum expansion. H = hot, hot fluid maximum expansion. Expansion can't take place in the radiator as it's a finite size. You're kind of right about the radiator drawing water from the reservoir, but this happens only when the temperature drops.

 

There is absolutely no reason for there to ever be too much water in the coolant system. If your theory were correct, do you think that you can remove the 'reserve tank' completely provided you put the right amount of water in? Cos my bet is that as soon as the water got hot and expanded, you'd have either a burst hose or water pissin through the rad cap as it's exceeded its pressure rating...

 

yes the cooling system does expand but that is all done in the rad those marks are to let you no when the overflow is full or empty you should keep a certain amount off coolant in there incase you coolant levels drop within the rad ( the pressure from the drop will suck coolant out of the reservoir back into the coolant system) and vis versa when there is too much coolant in the coolant system it dumps it into the reservoir

:duffer:

Sorry, but you are complettely wrong! C = cold... i,e, cold fluid, minimum expansion. H = hot, hot fluid maximum expansion. Expansion can't take place in the radiator as it's a finite size. You're kind of right about the radiator drawing water from the reservoir, but this happens only when the temperature drops.

 

There is absolutely no reason for there to ever be too much water in the coolant system. If your theory were correct, do you think that you can remove the 'reserve tank' completely provided you put the right amount of water in? Cos my bet is that as soon as the water got hot and expanded, you'd have either a burst hose or water pissin through the rad cap as it's exceeded its pressure rating...

 

 

sorry m8 but you need to check you info there is a small non pressured house going to that reservoir if it was used for expansion then you would have 2 pressure hose's not one the above pic is taken from the nisssan service manual i guess in theory you could remove the reservoir, look at a modern car that has an expansion take, has thick hose coming in at the top and a thicker hose coming out of the bottom, turn the enigine on and watch the water once up to temp circulate, you do not an i mean do not get expanison in the reservoir also the other clue to not geting expansion in the reservoir is the fact it does not have a pressure seal on the cap.

 

go look under your bonnet for yourself - i do no what i'm talking about seaing as i have just done a full conversion on my rad N/a to T/t :headvswal

i'm confused now, is my problem a problem or can i just leave it be??? Think modder is probably right as the level in the tank is constant

dutchy drain a bit of collant out of the reservoir so its about half full and just dont worrie about it, i would check you rad cap if the lower rubber seal looks bad then just replace the cap but it sounds like your zed is fine to me

ok will do so, cheers for the help, nice one.

Another possibity is a tiny water leak in one of your hoses, the hole can be so small that only a tiny amount of water can get out, and it will probably evaporate before it hits the ground, but through this hole it will also suck air in once the engine is switched off, thuscausing the system to bubble a bit and force water past the rad cap and into the resevoir bottle.

 

If i were you id fit a new rad cap as they only cost a couple of quid, top up the rad, take it for a run then when you get it home park it over a sheet of cardboard and when you shut it off stay looking under the bonnet for a good hour or so while it cools, you need to listen for the slightest little hiss or bubbling sound.

 

The water hoses on the rear of the engine are prone to perishing as they are exposed to massive extremes of heat.

 

As for the comments above on expansion tank/ resevior tank as far as im aware its a resevior tank which uses the same pipe to dump excess and suck back shortage, and it will only suck back a shortage when the engine is off and cooling down because if the fluid is low it creats a vacuum in the cooling system, BUT if you have even 1 leaky hose it will not suck back water from the tank as no vacuum is created becouse air is sucked in through the faulty hose instead.

 

Hope this makes sense.

:duffer:

Another possibity is a tiny water leak in one of your hoses, the hole can be so small that only a tiny amount of water can get out, and it will probably evaporate before it hits the ground, but through this hole it will also suck air in once the engine is switched off, thuscausing the system to bubble a bit and force water past the rad cap and into the resevoir bottle.

 

If i were you id fit a new rad cap as they only cost a couple of quid, top up the rad, take it for a run then when you get it home park it over a sheet of cardboard and when you shut it off stay looking under the bonnet for a good hour or so while it cools, you need to listen for the slightest little hiss or bubbling sound.

 

The water hoses on the rear of the engine are prone to perishing as they are exposed to massive extremes of heat.

 

As for the comments above on expansion tank/ resevior tank as far as im aware its a resevior tank which uses the same pipe to dump excess and suck back shortage, and it will only suck back a shortage when the engine is off and cooling down because if the fluid is low it creats a vacuum in the cooling system, BUT if you have even 1 leaky hose it will not suck back water from the tank as no vacuum is created becouse air is sucked in through the faulty hose instead.

 

Hope this makes sense.

 

 

Makes perfect sense to me i did not realise it only draws water back in when cooling :duffer: