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Acceptable length of cooling hose
shindha - 20/12/16 at 12:42 PM

In our build we have decided to run a long length of silicone coolant hose nearly 24 inches is 50mm in diameter when running the engine I find this is not a problem but when its cooling down they seem to collapse the engine is a 1.8 silvertop zetec. There is coolant running out of the "radiator" cap which is on the coolant bottle the radiator is a VW polo rad.
My question is, is it the length of silicone hose that's doing this or the rating of the cap I think it was rated at 18psi.

matt5964 - 20/12/16 at 12:56 PM

Can you not use a section of alloy straight tubes to stop the collapsing

sdh2903 - 20/12/16 at 12:56 PM

50mm seems large, is that OD? Most ive seen are 32mm ish on fords and into polo rads?

If its collapsing easy solution is fit an alloy pipe in its place or buy some of the wire reinforced flexible silicon hosing. The collapsing pipe is going to cause all sorts of pressure locks and funny behaviour.

The rating of the cap seems fine unless its duff, wouldnt be the first time. A new cap may be the cheapest thing to try first.

[Edited on 20/12/16 by sdh2903]

shindha - 20/12/16 at 01:02 PM

It might be 32mm I'm at work at the moment and not 100% sure but I did measure the run last night and it is nearly 2 feet, I think it will have to have a alu section stuck in, and a new cap any recommendations where from??

sdh2903 - 20/12/16 at 02:23 PM

Is it the vauxhall corsa style header tank?

shindha - 20/12/16 at 02:30 PM

The header tank is an aluminium one.

nick205 - 20/12/16 at 02:39 PM

I guess the obvious choice would be to use shorter runs of hose and an Aluminium length of pipe.

On the basis that cooling liquid contracts in volume I can imagine it collapsing a long run of hose. That said I've not seen OEM hoses collapse on cooling - perhaps their systems are vented in some way?

SJ - 20/12/16 at 03:01 PM

I found 32mm metal vacuum cleaner pipe from a Henry hoover works great.

adithorp - 20/12/16 at 03:17 PM

If the cap is losing coolant under pressure then thats your issue.

dinosaurjuice - 20/12/16 at 05:07 PM

If its collapsing when cold the cap is either bypassing at a lower pressure than it should be or the expansion/header tank is too small.

Adamirish - 20/12/16 at 08:05 PM

quote:
Originally posted by SJ
I found 32mm metal vacuum cleaner pipe from a Henry hoover works great.




Me too. It was only supposed to be temporary but has been on now for close to 2 years! If it ain't broke etc etc.

steve m - 20/12/16 at 10:02 PM

quote:
Originally posted by Adamirish
quote:
Originally posted by SJ
I found 32mm metal vacuum cleaner pipe from a Henry hoover works great.




Me too. It was only supposed to be temporary but has been on now for close to 2 years! If it ain't broke etc etc.


Errrr me too, 18 years and still going strong !!

Mine has two sections, one from the rad to the thermo housing, and one from the bottom to the water pump
also, its a straight push on fit, with out any beads

steve

Adamirish - 20/12/16 at 10:43 PM

quote:
Originally posted by steve m
quote:
Originally posted by Adamirish
quote:
Originally posted by SJ
I found 32mm metal vacuum cleaner pipe from a Henry hoover works great.




Me too. It was only supposed to be temporary but has been on now for close to 2 years! If it ain't broke etc etc.


Errrr me too, 18 years and still going strong !!

Mine has two sections, one from the rad to the thermo housing, and one from the bottom to the water pump
also, its a straight push on fit, with out any beads

steve


we aren't locostbuilders for nothing!

I must admit to flaring the ends of mine slightly as I didn't want it blowing a pipe off. I Warmed the pipe, big ball pean hammer in the end of the pipe and tap it with another hammer. Only flared about 3mm, in my head at least, the silicon hose can no longer come off.

Henry hoovers for the win!

britishtrident - 21/12/16 at 08:12 AM

The coolant tank pressure relief cap normally has a vacuum breaker valve to prevent a partial vacuum forming in the system.

nelmo - 21/12/16 at 08:17 AM

It's possible the collapsed silicon pipes are allowing air to leak in as the vibrations move them around, creating airlocks and causing overheating?

Ally pipes don't cost much (even the non-Henry version ) so either replace or add lots of supports (cable ties will do) for the silicon. You don't want all that weight flopping about at speed anyway...

nick205 - 21/12/16 at 08:39 AM

quote:
Originally posted by steve m
quote:
Originally posted by Adamirish
quote:
Originally posted by SJ
I found 32mm metal vacuum cleaner pipe from a Henry hoover works great.




Me too. It was only supposed to be temporary but has been on now for close to 2 years! If it ain't broke etc etc.


Errrr me too, 18 years and still going strong !!

Mine has two sections, one from the rad to the thermo housing, and one from the bottom to the water pump
also, its a straight push on fit, with out any beads

steve



Good use of what's at hand guys - well done!

The one issue I'd see for myself would be SWMBO asking where the vacuum cleaner parts were?

ianhurley20 - 21/12/16 at 11:18 AM

quote:
Originally posted by nick205
quote:
Originally posted by steve m
quote:
Originally posted by Adamirish
quote:
Originally posted by SJ
I found 32mm metal vacuum cleaner pipe from a Henry hoover works great.




Me too. It was only supposed to be temporary but has been on now for close to 2 years! If it ain't broke etc etc.


Errrr me too, 18 years and still going strong !!

Mine has two sections, one from the rad to the thermo housing, and one from the bottom to the water pump
also, its a straight push on fit, with out any beads

steve



Good use of what's at hand guys - well done!

The one issue I'd see for myself would be SWMBO asking where the vacuum cleaner parts were?


Another vote for Henry shiny chrome pipes. £7 from ebay. I made a sort of bead roller with a pair of grips with part of an exhaust clamp welded on and a disc of metal on the other jaw to press the metal between the sided of the clamp. A bit Heath Robinson but it worked fine and helps keep the hose in its place :-)

02GF74 - 21/12/16 at 09:53 PM

Im with BT on this. Surely the cap is two way, it should allow air out an in, else youd hear hiss of in rushing air each time you removed the cap.

adithorp - 22/12/16 at 10:47 AM

quote:
Originally posted by 02GF74
Im with BT on this. Surely the cap is two way, it should allow air out an in, else youd hear hiss of in rushing air each time you removed the cap.


It souldn't let air out unless the pressure reaches more than it's specified at (usually 1bar ish). That presure raises the boiling piont beyond 100c so as to prevent boiling. Even running below 100c boiling could occure in localised areas of the system (around the cylinders) if not pressurised. It should let air back in too... but if the vac' required to collapse the hose' is less than the amount to open the valve, then the hose collapses.
Cold it will have zero/atmospheric presure, engine runs, system heats, water expands, creates pressure in system, engine stops, system cools, water contracts and presure returns to zero/atmospheric. Only if pressure escapes will it have vac' when it cools.

02GF74 - 22/12/16 at 10:31 PM

quote:
Originally posted by adithorp

It souldn't let air out unless the pressure reaches more than it's specified at (usually 1bar ish).


How do you know it doesnt?

My gut feel is on the pressure exceeding that of the cap then air being drawn in when the water cools. And then again, maybe not, but regardless i still would expect the cap to allow air in so hoses retain original dimensions.

If i remember, ill measure the hot and cold levels in the header tank and change in volume to work out pressure.

Anyways, replacing by metal tube will keep the shape of the now sjorter length hoses.

02GF74 - 23/12/16 at 09:06 AM

Ignore what i said^^^^^

If the cap was opening due to excess pressure, gas would be vented, the gas would be air and water vapour so over time the coolanr level would drop. It doesnt so the above is incorrect.

Sorry to add to the confusion.