740 Dashboard heater vents!

[stephend]

Originally Posted by Laird Scooby

Could also be dodgy non-return valves in the vac lines - you know the non-return valve for the brake servo, they're like a small version of that.

Where are these 'ere vac lines, m'Laird? Wasn't aware of any vac lines running through the bulkhead from the manifold other than the very thin one to the ECU for the vacuum advance - but happy to be corrected...

[Laird Scooby]

Originally Posted by stephend

Where are these 'ere vac lines, m'Laird? Wasn't aware of any vac lines running through the bulkhead from the manifold other than the very thin one to the ECU for the vacuum advance - but happy to be corrected...

Good point! Sorry about that, i was forgetting it was an early one that's almost certainly cable operated. You can just see the non-return valve i'm thinking of just above the heater control valve but this is on my 760 :



If memory serves my old 740 had cable operated heater controls as well and having had a quick scan through my old pics can only see the ignition vacuum line, no others.

[Joe of Loath]

Good to know they're cable operated, I hate vacuum lines. Randomly occurring warm air isn't really on my list of maintenance items, as long as warm air comes out somewhere I'm happy!

[tofufi]

I think the difference is whether cars have air-con or not...

Air-con = vacuum lines to the heater control valve, non-air-con = cable operated valve inside the car by the front bulkhead