From: Dave Baker
Subject: Re: Sierra empties radiator
Date: 21 Jan 1999
>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
>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.
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. .