From: Dave Baker
Subject: Re: Sierra empties radiator
Date: 21 Jan 1999
Newsgroups: uk.rec.cars.maintenance

>From: "Tom Faloon" <Tom@TFaloon.Demon.Co.Uk>
>
>I have a 1983 Ford Sierra.
>
>It has been running without a thermostat for a long time, and everything was
>fine. I fitted one last week because I missed the heater in the cold
>weather.
>
>The problem.
>The temperature is normal. When I stop the engine it sometimes pours water
>out of the overflow pipe. It starts with a dribble and builds up to a flow
>of water.  If I lift the end of the overflow pipe up to be level with the
>top of the expansion tank, the water stops running out.
>
>The thermostat IS in the right way round. I checked the manual.
>There are no visible leaks.
>I have fitted a new radiator cap. (On the expansion tank. The radiator
>doesn't have one.)
>I am not overfilling it.
>The top quarter of the radiator is always cold. I think there may be an air
>lock, but if so how do I move it?
>
>Any ideas would be appreciated.
>
>Tom Faloon


I'd start by checking the routing of all the hoses and make sure none are
running higher than the expansion tank as this will cause an airlock. I once
had a problem with a Sierra where a hose was routed over the cam cover instead
of round it. A drain and flush the rad would be a good idea and perhaps a rad
test as Chris suggests. Then fill her up and start the engine with the cap off.
Squeeze the hoses all round to make sure they are full and after a couple of
minutes top up the tank to the right mark.

Also you could try routing the overflow pipe so it loops up a bit and then back
down. Finally a pressure test of the system would be a good idea even though it
has a new cap on. You can do this yourself with a foot pump and a bit of
ingenuity in making an adaptor. It should hold 15 psi or so.


Dave Baker at Puma Race Engines (London - England)  - specialist flow
development and engine work. .