Bleedin' radiator! HELP/discuss pls......

[ROD]

850 Reliant engine..........Some on here may recall that quite a while back I asked about probs caused by trapped air in the system.I am running with the pipe from water pump to back of head,and the rad is about 2" lower than it should be in a Reliant.No dramas with the system,as only used it for shortish runs. But... went for a blast down the bypass,held it at a steady 60 mph.and here we go again,spluttering out of the rad cap ( 7lb cap and pipe running horizontally from rad overflow stub on neck,turning down a tight 90 degrees  into top of a bottle.(bottle has fluid in it) .bottle top approx 2 " lower than pipe from rad.No cap on bottle . So..I checked the height of water in the rad,just below the filler neck.I then topped up the water by removing back end of the pipe that runs from head to w/pump ,stood the pipe vertical and topped it up ,took a fair bit.Now then.....If the water escapes it obviously leaves an air gap in the head to w/pump pipe,which is the highest part of the system.Whats the fix for this? ,bearing in mind Im going on 'the trip' to France/Spain on it next Saturday.                                            
 Im thinking zero rad cap,and let the overflow run into bottle and suck back out when cooling? Is the bottle too low? Should the bottom of the bottle be slightly higher than the rad cap?
 
 Ive also now fitted a t piece in the hose from w/pump to back of head to aid top up(highest point)
 
 This is confusing me,and p***ing me off!

[spanners]

fill the rad, fit the cap take the overflow hose and stick it in an overflow bottle that has a higher capacity than the amount that overflows, put a small amount of coolant in the bottom of the overflow bottle ,then make shure that the overflow hose dips into the coolant in the overflow bottle
and run it  ,,SIMPLE,S,,,

do not remove the rad cap when warm  but after a run when she,s cooled down  remove cap and chack the level and if you have a good system youlle find the level the same as when you first filled it
it expands into the overflow bottle the vacume sucks it back through the cap as it cools ..
 run large v8 race cars this way with only small header tank rads ,, even ford cortina p100 pickups used this system and they were built for the south african climate ..

[Olds]

The standard cap should suck back any excess liquid in the bottle as the system cools providing the pipe goes down far enough.
If you use a zero cap on the rad, the expansion tank will have to have a 7lb cap fitted and the pipe and fittings between the rad and expansion tank must be able to take the pressure.
I assume that you have checked the thermostat is opening correctly and that you have good airflow through the rad.
Is it possible that the system is being pressurised by combustion gasses?

[ROD]

Thanks for the input guys.Should the bottle be higher than the top of the rad?
 O N....combustion gasses as in head gasket kaput?
 Why does it still come out from under the cap? Dont know if it goes into bottle as its a stainless tank,will have to change it for a see through one.

[Olds]

Should the bottle be higher than the top of the rad?

Higher is better but not necessary. A few inches below should be fine.

 .combustion gasses as in head gasket kaput?

That's the problem I had.

[Olds]

Why does it still come out from under the cap? Dont know if it goes into bottle as its a stainless tank,will have to change it for a see through one.

If you mean that the liquid is not going into the bottle but dribbling all over the place under the cap the check that the hose to the bottle is clear and that the bottle has an air vent.

[ROD]

just been out there staring at it ,as you do! Looking at the watermark (tide mark) in the container,I reckon it was spluttering out from under the cap cos the container was full.It hasnt got much water in the container now,so I reckon it mustve pulled it back into the system,and the low level of engine water was due to the loss from under the cap. Its not very big,a lump of 2" diam stainless tube about 8" long.Im going to get a larger container tomorrow ,probably a drinks bottle or a flask,from the pound shop in Chelmsford. Ive already been rummaging in the bottle bank we have on site here (bloody pikeys!) ,cant see owt suitable.

[terry t]

 O N....combustion gasses as in head gasket kaput?

If the head gaskets gone then the rad will pressurize and the water come out of the tank . have you got an over flow pipe on the expansion tank. Anyway reliants dint have expansion tank on the cooling system it worked on a positive circulation type system

[ROD]

I did the head gasket myself,took great care etc,have re torqued head since .This only happens on a continuous hard run ,not on 40/45 mph around the town etc.

[andyrennison]

Ok, could it just be simple overheating Rod? Any clues to that?  Try running without the stat in the housing. If you don't lose water then you have a diagnosis. Clearly it's not a fix, but it will rule out compression gasses.

[ROD]

Time is ticking away on this,cos we go next Saturday. Have replaced the rad catch tank today with a larger capacity one.When Ive done engine swops over the years,Ive removed the stat to allow what I considered was better flow of coolant,never really had a problem,but some say the stat is defintely  needed to allow the engine to come up to temp after start up. Others say all you need is a plate with a hole in it to restrict the flow eg the bit of the stat with the hole,chop off the rest of it.I'm wondering whether to remove the stat and put the restrictor plate in. If it doesnt splurge out the overflow as before ,leave it at that,bearing in mind that we will be travelling in (probably0 much warmer climes.Anyone?

[terry t]

I would leave well alone.   
never heard of fitting a restricter plate. if the setup is as a reliant minus the heater it should OK. if you pressurizing the system then the setup is wrong rad to low or to small electric fan if fitted rotating the wrong way.
as for co gas in rad there shouldn't be any
as you said a bit late in the day to be playing with it

[ROD]

Just pulled the stat. It has 88 degrees stamped on it.
  Reliant manual says should start to open 86 to 89../..fully open 103.
  Im guessing the 88 degrees marked on it is the opening temp?
 Oddly enough,no water was present in the top hose,despite me topping up as previously mentioned!
 As also said previously,the rad appears slightly lower than it should be in the car,so that may explain no water in the top hose ,as it rises from the rad to the thermostat housing.
  Elec fan is from a m/cycle. good point about direction . It is mounted behind the rad,and Im pretty sure it is pulling the air through.

[andyrennison]

I'm not suggesting you travel without a stat. If you remove it and the problem goes away then its not compression gasses and you can put that aside and relax. While its out you can put it in a pan and see what tdnp it open at. All will take no more than a couple of hours. Diagnosis before cure

[hunter]

Rod put a filler in the middle of the top hose.