Radiator Hose.

[Southern Star]

I'm planning to renew my engine radiator hoses next week as preventative maintenance. It seems that hose is sold based on the internal diameter, and I can't measure this until I remove the hose, so is there a reliable method of calculating the internal diameter based on the external circumference (which is 1050mm), bearing in mind that I will have to remove the thickness of the hose wall from the calculation?

[Roger Crown]

Is there an extra zero in there? Engine age and make etc may be helpful in determining hose sizes.

Cheers

Roger

[bizzard]

Slacken off the old ones a bit and pull em back a touch so that you can measure with a caliper or vernier the pipe fittings they push on to. Ideally hoses with an I/D size slightly below that of the pipes O/D.

Edited August 15, 2015 by bizzard

[Scholar Gypsy]

Internal diameter = (external circumference)/pi - 2 x (thickness),

 

where pi = 3.14159......

 

You may get slightly different results at the end of a hose, where it is stretched a bit to fit on a spigot or pipe.

[Southern Star]

Yes, extra zero,apologies, it's a BMC 1.5 with a keel tank.

[FadeToScarlet]

I'm assuming there's no writing on the hoses?

[Southern Star]

I'm assuming there's no writing on the hoses?

No, here is a photo of the hoses I need to replace. As far as I am aware (and I'm willing to be corrected), these orange hoses are not suitable for the application, and they aren't marked in any way.

 

 

As the coolant is also of an indeterminate age, I want to replace that next week, and so replacing the hoses at the same time would seem to make sense. I'm hoping to buy the hose from a motor factor rather than a chandler because I am of fairly limited means, and while I can afford to maintain Desiree properly, I'm not inclined to spend £30+ more than I need to on the parts.

 

If anyone can tell from the photo what length and diameter of hose I need then I'd appreciate the advice.

[bizzard]

No, here is a photo of the hoses I need to replace. As far as I am aware (and I'm willing to be corrected), these orange hoses are not suitable for the application, and they aren't marked in any way.

 

 

As the coolant is also of an indeterminate age, I want to replace that next week, and so replacing the hoses at the same time would seem to make sense. I'm hoping to buy the hose from a motor factor rather than a chandler because I am of fairly limited means, and while I can afford to maintain Desiree properly, I'm not inclined to spend £30+ more than I need to on the parts.

 

If anyone can tell from the photo what length and diameter of hose I need then I'd appreciate the advice.

As I mentioned earlier, just slacken off each hose clip, pull back the hose enough to measure with a simple caliper or vernier the diameter of the pipes they go onto which will be the inside diameter of the new hoses you need, Ideally hoses with a very slightly less inside diameter than the diameter of the pipe stubs they fit onto. It might be worth getting a new thermostat and gasket too, because that short black hose connecting the manifold heat exchanger to the thermostat housing probably can't be replaced without removing the thermostat housing.

[NMEA]

Assuming a circumference of 105mm it will be either 32mm or 1 1/4" bore hose, more likely 1 1/4" unless it's really heavy wall in which case possibly 25mm or 1"

Edited August 16, 2015 by NMEA

[Southern Star]

As I mentioned earlier, just slacken off each hose clip, pull back the hose enough to measure with a simple caliper or vernier the diameter of the pipes they go onto which will be the inside diameter of the new hoses you need, Ideally hoses with a very slightly less inside diameter than the diameter of the pipe stubs they fit onto. It might be worth getting a new thermostat and gasket too, because that short black hose connecting the manifold heat exchanger to the thermostat housing probably can't be replaced without removing the thermostat housing.

Thanks, have ordered a set of caliper/vernier gauges now. I was hoping to order the hoses this week, but it can wait. Good point about the new thermostat and gasket too, thanks for the advice, I gave you a greenie. Hopefully I can revisit this thread if I encounter any problems when fitting the new hoses, I gather airlocks can be an issue on these engines.

[Cavalier Jon]

Having just done a temporary repair on the coolant system for a BMC 1.5l with 30mm hose - and struggled, I'm pretty sure you need 32mm hose. I was in Macc marina and that's what I was sold on the premise that it was for a BMC.