...I thought that would get your attention!

My x-flow cooling system is now working just as it should - almost. It's got an old-fashioned overflow/recovery tank instead of a pressurised header tank. As the engine heats up some water is ejected past the pressure cap (as it should) into the overflow tank.

The problem arises when the engine is turned off and cooled down - the system is meant to suck back the ejected water from the tank as everything cools, but it doesn't.

I can't see any obvious air leaks in the tank piping, and I do have the correct 2-way pressure cap.

Any ideas?

David

I use the same but my overflow bottle is a washing liquid bottle till I find something better (been on 2 years now) I had a problem with mine where the bottle was expanding under pressure so I had to make a breather hole in it. Also make sure the pipe from your radiator neck goes to the bottom of the bottle and put some water in there to submerge the end of it.

Pete,

OK on both counts! I've used a Daihatsu overflow bottle which seems ideal - it's big enough, easy to mount, has a tiny vent in the cap, and I've filled it to the 'MIN' level (about half full).

I've seen an ideal bottle on an american website - it has a fitting on the bottom of the tank where the pipe goes to the rad cap overflow. The down-side was its size - I reckon a US Quart might be a bit big to fit under a Locost bonnet!

David

Is the pipe into the radiator neck sealed, the one it pushes onto?. I araldited mine as it was weeping slightly

Pete,
I think you're on the right lines (always useful discussing a problem with others!) - I'll have to check all the pipework and maybe seal them up somehow. Doesn't take much of an airleak to reduce the suck...

David

Pete,

What type of rad cap are you using? I'm starting to wonder if I've got the right type...

Also, I had a look at the Haynes book of lies for the Escort, and originally it didn't use an expansion tank at all! It just says to fill the rad to within 1" of the top, and not to over-fill it as it will get chucked out.

Now this may be fine, but with the Fiesta thermostat cover I've got (with filler cap) if I leave it 1" below the top there's a risk that the fan thermo switch will be uncovered.

I'm confused...

David

(BTW: I do want to use an overflow tank)

[Edited on 6/7/04 by David Jenkins]

I used a mk2 escort rad cap. If you are using the fiesta filler I would block the hole in the rad and put a blank cap on there, just use a pressure cap on the stat housing. You should only have one pressure cap on the system. Then you can use a header tank like the later systems.

That pretty much describes what I've got already...

...back to finding the air leaks, then!

thanks,

David

This type of arangement never works in my experience any over flow from a hot engine flashes straight off into steam when the presure drops.

Triumph and Lotus both used in the late 60s early 70s but it never worked. Rootes put it on the first Hillman Hunters but took off after 6 months because it didn't help. My Rover 623 has it thanks to Honda and it dosent work on that either.

It did however work on military vehicles but they used a 2 gallon metal surge tank with steel piping both exposed to the air flow so it acting as a condensor , a little plastic pipe and bottle won't do that.

I have an header tank off a 2004 Golf GTI, but my micra rad has an overflow pipe to an expansion bottle.

Do you think I will need a higher rated cap for the rad, or just rely on the header tank to take up the pressure?