Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Heater hoses

Hi Everyone,

Went for a short run today, bit chilly but very pleasant under a blue sky, and when I got home did a cursory look over the engine compartment.

Checking the heater hoses I noticed the two smaller diameter hoses to the top of the plastic expansion tank were quite tacky to the touch (less so when cold).

On further investigation the hoses quite clearly state "fuel hose suitable for unleaded".

Does anybody have a view regards these two issues.

Thanks as always

Geof
70th Anniversary 4/4 Duratec

The hoses appear to be for fuel only? Please bear in mind that the hoses used for your water system are reinforced due to the high pressure in your cooling system where as the fuel system are not?

There may be pipes that can do both water and fuel but worth a check?

We use silicone hoses in our water system with stainless jubilee clips/clamps.

I don't think expansion tank hoses are under high pressure, are they?

I would have thought that most fuel lines are high pressure these days anyway with injection systems being the normal.

The expansion tank is pressurised. I have the same factory fitted fuel hoses on mine but they are not tacky. Beware of coolant system additives as some are no compatible with all hose materials.

I would have thought the issue here was the temperature not the pressure.

The fuel injection will be running at up to about 3 bar but the water system is only about 1 bar.

But is the fuel line rated to run at over 100 degrees C.

Is the hose softening slightly at the higher temperatures?

That was kind of my point. The blow-off pressure of an expansion tank is what, around 14psi?

What's the pressure of a fuel system? More like 60psi.

That's why I said it's not under high pressure.

Found a pic with the spec of the moderately pressurised hose

Hi all,

From what I have gleaned I think I can say, in very general terms, fuel hose can be used for cooling systems but not cooling for fuel. But thank you to everyone for your comments which put me onto the right track.

Roger, yes the hoses are exactly as your piccie and I've just re-inspected them - not tacky. So it would seem a chemical change as they get warm. I haven't use additives, only Morris universal anti freeze. Whole wealth of info on tacky rubber on the Internet. (Including web sites of notoriety!)

I will play safe and replace. Bit of a bu---r really since one disappears to the back of the block (or head) and seems a bit fiddly

Regards for now

Geoff
70th Anniversary 4/4 Duratec

I take your point Bob, what I was pointing out was that the fuel line would withstand more pressure than a water hose.

Below are some interesting facts on fuel lines.

https://www.hemmings.com/blog/2014/12/05/tech-101-fuel-line-hose-what-you-should-and-should-not-use/