Technical Heaters airlock?

[Venters]

Right had to disconnect a couple water pipes on the engine today to put the manifold heatshield back on.

Now when I put the heater on I get no heat whatsoever until I turn it to it's maximum setting, instead of the progressivley hotter air as you turn the heat up.

Now I've run the engine till warm and and bleed the rad from the 2 plastic screws at either end of the top of the rad.

Is there something I have missed?

 

[Renegade_8]

I was concerned this might happen when I changed my thermostat(I'm now convinced the temp gauge was lying!)
The Haynes manual tells you that heater air locks can happen, and tells you to loosen the heater hose bleed screws. My 1.8 did not have any! I just filled it slowly slowly with the rad hose bleed screws open, squeezing the bottom and top hoses as I went, when clear coolant without bubbles was coming from the bottom one I closed it and carried on until coolant came out of the top one, squeezing both hoses all the time. I then ran the engine, the heater worked straight away i let it come up to temp, topped up the expansion tank when it had cooled down and its been fine since. I was careful to squeeze the hoses close to where heater taps in. You might get lucky by looseneng the top hose to the heater and squeezing the pipe the other side, otherwise i would drain and re-fill sloooowly as above.

 

[Venters]

I was concerned this might happen when I changed my thermostat(I'm now convinced the temp gauge was lying!)
The Haynes manual tells you that heater air locks can happen, and tells you to loosen the heater hose bleed screws.

Don't know if My 20V does have the heater bleed screws and don't know what the heater unit looks like either.

Looks like I'll have to follow the pipes!

Cheers

 

[Venters]

Well I think thats it all fixed.

Followed another of the pipes from the rad and saw a bleed screw on a pipe going round to the back of the engine, I'm assuming this is the one of heater pipes.
Loosened that for a bit seemed to help.
Took it for a spin and bleed all 3 screws again. Lessoned learnt on how to do it ( 3 foot jet of water and a scalded hand! )
And now it seems like its good as new. :slayer:

 

[jug]

3 foot jet of water and a scalded hand!

sounds like fun

 

[Venters]

It's the kind of mistake I hope to make only once.

 

[Renegade_8]

topped up the expansion tank when it had cooled down

Maybe I should have put that bit in red? OT if you have a pre war car it will not have pressurised cooling system, you can drive into a garage and just remove the filler plug and no jet of scalding water. Watching the faces of people who have learnt the hard way not to do this with pressurised sytems is priceless
Sytems are pressurised because it elevates boiling point allowing you to work the coolant harder.

 

[Venters]

the Jet came from one of the bleed screws. Must have turned it too far crapped myself and drew my hand away so fast I threw the bleed screw.

Took ages to find it!
Dam I love Savlon!