Coolant Disappearing

[aagun]

Originally Posted by Grimlock

What is this 'fix'? The guy edited his post and nothing is shown.

without the tape , the coolant will go away with in 250km at speed 180km , before i start the trip the coolant lvl at full and after the trip the coolant lvl under the low

[tebriel]

if you guys really want to seal it up, thread a plastic or brass nipple in the overflow tank hole, cut the hose to size and clamp it on there.

[Hanakuso]

Originally Posted by tebriel

if you guys really want to seal it up, thread a plastic or brass nipple in the overflow tank hole, cut the hose to size and clamp it on there.

I'll probably do that once my warranty runs out.

[notout86]

Originally Posted by JDKane527

If you seal the area around the hose to tank interface, are you also sealing the breather hole at the top of the tank?

I have looked at the system and cannot see how sealing around the point where the tube enter the top of the bottle can help significantly as the breather hole area is much larger.

I believe that (providing no internal coolant leakage or burping from within) the only way the level can go down is from evaporation via the breather hole. Only a pinhole is enough to allow pressure equalisation to prevent the overflow bottle from ex/im-ploding and another car of ours had only a pinhole. A pinhole could conceivably block I suppose. I have reduced the size of our breather hole with blutac and covered with some foam as an anti-solids (grit,bugs) filter and to slow air rushing past which might speed up evaporation.

To minimise the temperature of the coolant in the bottle I have added an aluminium foil heatshield around the bottle vs engine and radiator radiant heat. There is an air gap between the bottle and shield allowing cool air to convect up inside when the engine is off and condensation to occur earlier. There is an inspection slit to check the level.

"Bloody Hell, but Does it WORK?" I hear your strangled cry. It does a bit... coolant disappearance rate has halved.

[notout86]

As people are not seeing any evidence of leakage, I wonder if any rubber pipes in the system (including to the cabin heater) are slightly permeable to a coolant component. What is that white stuff on the rubber?? It comes back a while after cleaning.

[notout86]

Thinking about this more, I suppose if the overflo bottle (which has an opening to the atmosphere, which allows evaporation) was replaced with a bladder similar to a wine cask then the system could be completely sealed.
This would also mean that no atmospheric oxygen is being absorbed into the coolant in the bottle which goes back and forth to the engine, gradually causing oxidation/corrosion.

However, with the existing system, perhaps it is a good thing to be forced to occasionally add a small amount of fresh coolant as anti-corrosion chemicals are being consumed and need replacing.

I want to see a double-blind crossover trial run for both systems

[notout86]

After I checked to understand the system and what people were talking about with sealing where the overflo tube goes into the top of the bottle I created a monster.
I pulled the tube out to inspect it. When I pushed it back the tip caught somewhere inside going down the bottle and kinked back on itself. When I popped the bonnet next day there was dried coolant spots all over the engine compartment and the tube had blown off where it attaches near the radiator cap.

Also, the tip of the tube down the bottom of the bottle was cut at an angle such that it might seal against the wall of the bottle when the coolant should be sucking back to the radiator. I cut a few notches in it just in case.

[notout86]

Originally Posted by notout86

I have reduced the size of our breather hole with blutac and covered with some foam as an anti-solids (grit,bugs) filter and to slow air rushing past which might speed up evaporation.

If anyone doubts the wisdom of a filter over the breather hole, take the top off the overflow bottle and look down inside. You will see rubbish directly below the hole, or at least evidence of where it was before you washed it off when the coolant was topped up.

"Cleanliness is next to Godliness"

[notout86]

Originally Posted by aagun

without the tape , the coolant will go away with in 250km at speed 180km , before i start the trip the coolant lvl at full and after the trip the coolant lvl under the low

You must check levels when the engine is cold, and even then the ambient temperature and how quickly the engine cools can make a difference.

[notout86]

Some people (me included) had rapid drops in level in the first few months.

One cause could be air boiling out of the coolant. The coolant is stated to be 50/50 water. There will be dissolved air in the water component. When the coolant temp rises, and especially as it contacts hot spots where it will vaporize, that air comes out. Eventually it will end up burping into the overflow.

My previous car used a coolant concentrate that was diluted 50/50 with water.
To reduce the dissolved air (oxygen which causes corrosion and air in general which boils out at hotspots causing cavitation) I would first boil the (distilled) water first to drive out the air, then keep it covered while it cooled. I don't know how much this theoretical fussing helped, but, at 210,000km my water pump was inspected and was "as new".

[kodyo]

In the same spirit as the tape, I used a rubber grommet to seal the hose to the tank. Had to drill out the tank inlet hole a bit, but this can be done pretty easily with just a drill bit (no drill needed, plastic is soft enough to do with hand only). Used a piece of packing tape to prevent debris from falling into the tank. Grommet and final result below.

[notout86]

If you think about it, I believe you will realise that it is misguided to ensure the tank is sealed.

It should be open to the atmosphere to allow air displacement as coolant expands into the overflo tank and air goes back in as coolant in the radiator contracts as the system cools.
If the bottle/tank was completely sealed it would be bulging and collapsing. It is not flexible like a bladder. THERE IS A BREATHER HOLE AT THE TOP OF THE AIR SPACE but it is concealed under the metalwork. If the car tips over coolant will come out. A flexible bladder would be the ultimate.

In my opinion that hole is too large and allows dirt (and possibly insects) in & if you open the bottle cap and look inside you will see dirt below it. A bit of open-cell foam to act as a filter over the hole is a good idea. The hole should NOT be blocked/sealed.

Please correct me if I am wrong.

[kodyo]

I agree with you about not sealing the tank. Im sealing around the hose and likely going to put a breather plug in the location of the pin hole. Gonna see if that helps any over time. My thought is that coolant droplets will tend to collect and fall out of the gas as it tries to go through the foam/breather plug similar to a demister, assuming that's the real issue here.

[2016 Camaro SS]

My coolant disappearing issue went away when I changed the hoses to silicon ones and the clamps to t-bolt style. I changed nothing with the overflow tank and it's still at the same full mark when warm.