Correct width of rubber vacuum hose on top of heater valve of series 3 XJ6 1986

Please excuse the repetition here on a post from several months ago which I cannot find. I want to replace a section of that hose, I think it’s a quarter inch, but want to confirm that before I head out to the local auto parts store. Thanks.

Mel R.

From memory the spigot of the heater valve must be about 4mm. Vacuum hoses are quite flexible and exact diameter is not very critical.

Thank you Aristedes. I just want to make sure I can cut off the damaged portion and then connect it to the rest of the hose with a ‘T’ type (without the’I’ portion) connection.

So I disconnected the vacuum hose from the heater valve, cut off the small damaged section of that hose, and took it with me to the auto parts store where the guy behind the counter matched if to vacuum hose they have on a large spool which they cut and sell by the foot (30 cm). I bought two feet. When I told him i need a connector he pointed me to a specific product they sell , a spool of a narrower plastic hose which slides with a bit of difficulty into the rubber replacement vacuum hose. I haven’t yet had time to drive the car to evaluate, but I am feeling cautiously optimistic this fix may work.


I think it was this topic: Auxilary fan in front of radiator not working 1986 XJ6 series 3 - #44 by davidsxj6

While you are at it, Mel; check vacuum on the hose with the system in full cold, engine running - you should read manifold vacuum. And vacuum should be retained when you turn off the engine…

xj6 85 Sov Europe (UK/NZ)