MattRwebB Posted October 29, 2015 Share Posted October 29, 2015 Where is this hose supposed to go comes of my over flow tank to nothing I don't have any coolant in my overflow tank either ... is that ok ? guessing it just hasn't over flowed ... Can't se how coolant can go back into the system if there is only one pipe going in from the Rad cap on top of the thermostat (left side) and then the right side pipe doesn't go anywhere :s (I've just drained coolant out and replaced) 350z HR 57 plate Quote Link to comment Share on other sites More sharing options...
Watshot Posted October 30, 2015 Share Posted October 30, 2015 (edited) They are correct. Assuming the left hand pipe from the rad cap is attached to the entry on the bottom of the expansion tank. The top pipe is an overflow and exits to air lower down on the right hand side (as you look at your photo). The tank is also a reservoir so should be filled between the min and max lines marked on the back. Fill using the cap on the tank. It won't fill itself from the rad cap when cold. The system is notoriously difficult to drain and fill. Access to the drain plugs on the block is limited, and air locks are common (have you used the bleed valve behind the block?). You can check here for the correct Nissan procedure: http://www.nicoclub....Coupe Roadster/ section marked 'COpdf' page 9. Or search the forum for other users experience and recommendations. Also, possibly too late, but best to refill with the original Nissan spec coolant. And yes, the system regulates itself through the single pipe. Best of luck. Edited October 30, 2015 by Watshot 2 Quote Link to comment Share on other sites More sharing options...
Toon Chris Posted October 30, 2015 Share Posted October 30, 2015 I'm going to 'Like' this because its a perfect answer and needs a pat on the back as bang-on assistance Quote Link to comment Share on other sites More sharing options...
veilside z Posted October 30, 2015 Share Posted October 30, 2015 That's the beauty of this forum. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted October 30, 2015 Share Posted October 30, 2015 I think the main question, as in why and how needs to be answered, the tank is an expansion tank, and as such should be filled to the mark as said, the pipe that comes from the thermostatic cap be it on a rad or the engine coolant pipework in this case, and goes into the expansion tank, Its there to allow the cooling system to breath as such, if you heat water it will expand, so when the engine is switched off and the rad is no longer doing its job, the coolant will inevitably overheat via induction, this over pressures the system and the coolant is forced past the thermostat and into the expansion tank, As the engine cools a partial vacuum occurs, and as the pipe from the cap thermostat is designed to allow coolant to be sucked back into the system, because this pipe is (should be) always below the coolant level in the tank, the problems arise when this expansion tank is allowed to go low or dry, which is why the OP is likely having trouble with air locks. 1 Quote Link to comment Share on other sites More sharing options...
Toon Chris Posted October 30, 2015 Share Posted October 30, 2015 I think the main question, as in why and how needs to be answered, the tank is an expansion tank, and as such should be filled to the mark as said, the pipe that comes from the thermostatic cap be it on a rad or the engine coolant pipework in this case, and goes into the expansion tank, Its there to allow the cooling system to breath as such, if you heat water it will expand, so when the engine is switched off and the rad is no longer doing its job, the coolant will inevitably overheat via induction, this over pressures the system and the coolant is forced past the thermostat and into the expansion tank, As the engine cools a partial vacuum occurs, and as the pipe from the cap thermostat is designed to allow coolant to be sucked back into the system, because this pipe is (should be) always below the coolant level in the tank, the problems arise when this expansion tank is allowed to go low or dry, which is why the OP is likely having trouble with air locks. Sorry, only one 'Like' per thread, it's a personal rule Quote Link to comment Share on other sites More sharing options...
MattRwebB Posted October 30, 2015 Author Share Posted October 30, 2015 ok thanks ! I've drained my coolant from the Rad and then filled back up with water ... ran it for 10 mins then drained again (both times just used the bolt under the RAD) ... and filled with comma coolant (pink) last owner had pink in there so used the same didn't use any bleed valve .... then once the coolant was brimmed at the top of the RAD cap ran it for 10 mins to let bubbles come out but didn't get much lower just a little top up hear and there for the last few days ... don't have any coolant in the overflow tank was confused to see how the water went back in and thought it was a bit pointless but the vacuum it creates makes sense! so shall i just add count to the overflow to the max ? as long as no more bubbles come out of the Rad cap and i fill the overflow I'm good yh ? (again didn't use any bleed valve) Quote Link to comment Share on other sites More sharing options...
Jp606 Posted October 31, 2015 Share Posted October 31, 2015 You're meant to fill it in the cap with the bleed valve open until it pushes all the air out the bleed valve and starts to overflow with coolant, otherwise you risk getting an airlock. After that you fill the reservoir up to max. I've only ever used genuine Nissan coolant for the 350Z which is green, so can't comment on whether the pink stuff is ok. I know you're not meant to mix them together though as it turns to jelly and blocks things up. Quote Link to comment Share on other sites More sharing options...
MattRwebB Posted November 1, 2015 Author Share Posted November 1, 2015 Yh that's what I read but as it was pink before I used pink again to stop that from happening ... Also ran water through it Yh didn't use the bleed valve Plus when i leave the rad cap of to let bubbles come out it keeps over flowing! Only had it running for 10 -15 mins or so Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
Watshot Posted November 1, 2015 Share Posted November 1, 2015 Couple of problems you may have now Matt. The system is pressurized so it's going to keep pushing coolant out if you run it with the rad cap off. But perhaps more importantly, as you only drained the radiator and not the block, then flushed with water (running the motor both times), you have diluted the coolant that remains in the block. Refilling the radiator with a 50/50 mix will dilute further once run and mixed with whatever was left in the block. You probably don't have the recommended 50/50 protection required. It's a good idea to drain into a bucket and measure how much of the 7.9 litre capacity you have removed, then you have a better idea of what you need to achieve when you refill. Also, try and drain the block. Follow the manual I linked to in post 2, but in a nutshell; fill slowly with the bleed screw open, (close everything) then run until warm, cool down, repeat. And yes, fill the reservoir to the 'max' line. Quote Link to comment Share on other sites More sharing options...
MattRwebB Posted November 2, 2015 Author Share Posted November 2, 2015 Ok didn't even no you had to drain the block as well ... all learn at some point lol ... I will probz drain it all again out the rad .. then the block ... do everything back up and undo the bleed screw ... pour coolant in again until coolant comes out the bleed screw ... do bleed screw back up ... fill up the rad cap and reservoir ... warm up engine ... cool it ... fill up again from rad cap if needed, and agin if needed ... Am i supposed to let bubbles out at all while engine is running ? Quote Link to comment Share on other sites More sharing options...
Watshot Posted November 2, 2015 Share Posted November 2, 2015 Don't open the system whilst the engine is running. Any air 'bubbles' should escape from the bleed screw when you're filling up. Also remember to open the heater valve to drain/refill all of the coolant. The system will draw coolant from the reservoir if it needs it. Once it has cooled down, the level on the reservoir will show whether it has dropped or not. If it has, top it back up to the 'Max' mark. (You don't have to top it up at the rad cap). If you have a problem, air lock, etc. wait until it has cooled, open the bleed screw, keep topping up slowly through the rad cap, repeat until the level remains constant at the max mark when cold. If you measure the amount of coolant/mix when you are filling the system, you will have a better idea whether you are near to the correct capacity or not (remembering how much, if not all, you managed to drain). Irrespective of this, never over fill above the max mark (checked when cold). Due to the difficulty with draining the block, some folk just drain and refill the radiator. this is okay if you do it often enough as it will reduce the amount of old coolant left in the block as it mixes with the new each time it is changed. The problem is, you introduced pure water into the mix instead of coolant when you were flushing the system, and this just dilutes it too much. To be honest, I couldn't find one of the two drain plugs on the block (or couldn't get to it, can't remember), but I drained 7 litres plus, so the half litre or so that was left behind wasn't an issue. But I had no need to flush the system, but if you do yours again it will have had a reasonable flush now anyway. Just take your time when filling. Quote Link to comment Share on other sites More sharing options...
ZMANALEX Posted November 2, 2015 Share Posted November 2, 2015 (edited) Sorry link not working, bear with me. Edited November 2, 2015 by ZMANALEX Quote Link to comment Share on other sites More sharing options...
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