The coolant overflow bottle located inside the passenger side wing in mine now has a hole in it due to my suspension set up letting the wheel just catch the very edge of it! i am looking at getting a smaller size bottle or alternatively getting one fabricated from aluminium that is slightly narrower. Anyone done this or any suggestions as to what to do?

Is there nowhere else you could relocate it? The OEM position is shat to say the least.

Surely there isn't really a need for the bottle? The pipe has no way to return the fluid to the engine and is merely there to catch any drips that the cooling system might expel via the radiator cap.

 

I remember on slightly older cars these pipes would just be clipped to the rads and any excess fluid just dripped onto the road, I wondered if the japs fitted the tanks for eco purposes, ie not just letting anti-freeze etc drop on the road.

 

I'm interested to know the answer to this :confused:

I think they are there for when the engine gets really hot and it can dump some of the coolant into the bottle and suck it back up when it is cooler. Not sure though?

I think they are there for when the engine gets really hot and it can dump some of the coolant into the bottle and suck it back up when it is cooler. Not sure though?

 

This would be physically impossible as the radiator cap would need to pressurise to open, but it would be pressure and not suction and would therefore be dumping more coolant.

i know when my Pajero had a coolant leak it would use the coolant in the expansion tank

The pajero has the rad cap on top of the expansion tank (like my delica), therefore it is also pressurised - the Zed overflow tank isn't.

I guess another way to think of it is like a tyre valve - being pressurised it can let air out if faulty, but has no way to draw the air back in from the atmosphere to replenish automatically.

The rad cap also has a vacuum release section so that coolant IS sucked back into the system when it cools. Have a look, it's the smaller seat in the centre of the main seal.

 

You can fit a smaller bottle in there pretty easy, I did one years ago, should be some pics on here somewhere. Main advantage is that it clears the airflow out the back of the intercooler.

The rad cap also has a vacuum release section so that coolant IS sucked back into the system when it cools. Have a look, it's the smaller seat in the centre of the main seal.

 

You can fit a smaller bottle in there pretty easy, I did one years ago, should be some pics on here somewhere. Main advantage is that it clears the airflow out the back of the intercooler.

 

Cheers John, exactly what i needed to know. I will see if i can find pictures, can you remember where you got the smaller bottle?

It was some sort of chemical sample bottle from my old work.

Try http://www.carbuildersolutions.co.uk, pretty sure one of their washer jet or coolant tanks would do.

The rad cap also has a vacuum release section so that coolant IS sucked back into the system when it cools. Have a look, it's the smaller seat in the centre of the main seal.

 

You can fit a smaller bottle in there pretty easy, I did one years ago, should be some pics on here somewhere. Main advantage is that it clears the airflow out the back of the intercooler.

 

At least I know now that there is a point to the bottle. I never realised a vacuum formed - I've only ever experienced pressure when releasing the cap even when cold.

Cheers for clearing that up though.

dam wish i never click on that link John just cost me a small fortune lol