Heater hoses

[rufus1]

Hi
I have a MK1 with 1-3/4 su's the manifold is the type with the
large plug in the end where the heater hoses attach.
When the engine is up to temp the hose into the manifold, thermostat
end, is hot but the two heater hoses, one goes to the heater
the other to the valve, are cold and therefore I have no heat in the car
The valve is moving ok and the fan is working. Conflumaxed!!
Help please?

[englishbull]

Heater matrix blocked?.

[rufus1]

Hi
You did mention that before didn't you?
Would the hoses be cold if that was the case?

[Alec]

Hello Rufus,

the first thing I would check is to see if there's an airlock, disconnect the hose that goes to the steel tube that runs behind the manifold, with the engine running to see if there's any flow. I would do it from cold so as to lessen the risk of scalding. Make sure the radiator is topped up when you do this, and if there is nothing after some time then it looks like the matrix is blocked as suggested. I would, however also look at the valve in case some debris is blocking it?

Alec

[Dave B]

Also could be the water passage through the manifold is obstructed, if it is hot at one end and not the other.
Initially I would try disconnecting the hoses and try flushing both the manifold then then the heater unit with a mains pressure hosepipe to confirm there is a good flow through each.

[tony]

At the firewall end there's a tee piece where the hoses seperate to the heater and the return to the pump. There's a small drilling here that can get blocked and stop circulation. It happened to me.
Sorry, just re read your post, maybe a Mk1 is different.
Tony.