Overflow bottle makes my car over heat?????

[krbrooking]

As the title states, I have been driving my car without the overflow bottle in to try and sort out why my car was overheating, since not having it in it has not gotten hot at all but I put it back in on the weekend to see if it was that or the water pump as I removed it when I replaced the water pump a little while ago. It has just over heated on me proving that it is the over flow bottle.
Has anyone ever heard of this problem before??
I have check the bottle and there dose not seem to be any cracks or leaks.

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[Bloodyaussie]

That is very odd ???? very curious to see what it could be.

[Cuppa]

When you removed the overflow/expansion bottle did you just block off the hose? .....or?
When you refitted it did you do so empty or partially filled?
When the overheating occurred what happened to the overflow/expansion bottle, did it’s contents level rise or fill completely?
When the motor cooled did the radiator ‘suck’ back any coolant it had pushed into the bottle?
Has the radiator coolant level dropped?

I don’t know what might be going on, but the answer to those questions might assist others to help.

I’m wondering how the radiator coolant was able to expand when it got hot with no bottle fitted, and if with the bottle refitted if it’s breather may be blocked.
No expertise just wondering aloud.

[Parksy]

Has the radiator cap been replaced with correct pressure type? Did you block the overflow hose when the bottle was removed?

[Hodge]

For what it's worth mate, my old VS commodore was overheating, and my local mecho removed and bypassed overflow bottle until he could book me in. I can't remember why he done that and he did explain it to me. But this was 15,years ago. Problem ended up being a water pump. Between the time he bypassed it and when it got fixed it never went above 3/4 on the gauge.

[krbrooking]

Ok to explain a bit more when I removed the overflow ( pressurised ) bottle I left the secondary ( unpressurised ) over flow in. I blocked off the hose that came from the block to the bottom of the pressurised bottle and redirected the expansion hose from the radiator to the bottle left in the car so it could still expand.
When it over heats it bubbles from the hose coming from the block to the pressurised bottle which then pumps into the secondary bottle and then straight out the over flow "funnel" essentially dropping the coolant, to the extent it can take around 7 or so L's to fill back up. So I am not sure if the radiator sucks it back as there is pretty much nothing left to suck. I have also replaced both caps so is unlikely the cause.
I will take pics this arvo and show what I mean once I have had some sleep to help explain what I mean.

[Alitis007]

That bottle your talking about is a surge tank, the over flow/ expansion tank sit beneath it.

Last time i looked at your car Kev i thought that surge tank was leaking coz it was cracked ?? If my memory is correct and it is cracked in theory whats happening is the coolant expands into the overflow bottle but at the coolant cools down and contracts the cooling system is drawing in air and not the coolant from the overflow ( lower bottle) which over time keeps emptying the surge tank and radiator system. If you remove the bottle again make sure none of the hoses are blocked either

[kevin07]

That bottle your talking about is a surge tank, the over flow/ expansion tank sit beneath it.

Last time i looked at your car Kev i thought that surge tank was leaking coz it was cracked ?? If my memory is correct and it is cracked in theory whats happening is the coolant expands into the overflow bottle but at the coolant cools down and contracts the cooling system is drawing in air and not the coolant from the overflow ( lower bottle) which over time keeps emptying the surge tank and radiator system. If you remove the bottle again make sure none of the hoses are blocked either

now that makes sense

[P4trol]

As the plastic degrades further, you will see pale green spots where the leak is in the plastic tank, where the coolant is leaking out.

[krbrooking]

Well ripped the bottle out this arvo. Before I started.

44263

] This is the hose coming from the block 44255 This is with the surge tank removed, notice the wet spots. 44256 44257 This is how I blocked the hose and diverted the over flow hose into the over flow bottle. 44258 44259 Where I am pointing is where the coolant is getting pushed out of, it must be like an over flow funnel. 44260 I hope this helps with understanding what is going on. Sent from me using Forum Runner

[Alitis007]

That port is to purge the water when the overflow fills up. Like i said the bottle you removed was the surge tank

[krbrooking]

That port is to purge the water when the overflow fills up. Like i said the bottle you removed was the surge tank

Yeh the surge tank pushes the water into the lower bottle then flows out that port once it starts bubbling.
Could it be the cap not sealing properly on the surge tank essentially sucking in air that way as I don't think it is sealing properly.

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[Alitis007]

If it isn't sealing then yeah the cap can suck air. Dunno if this will work but it worth a try, block all the holes on the surge tank a part from one fitting that you can attach your compressor ( the 1 you use off rd) to so you can pressurize 15psi, then hold it in a tub of water and see if air escapes. That should give you an indication if its sealing or leaking