View Full Version : Rover air lock.

28-04-01, 06:48 PM
I've heard about Rover air lock problems but when I filled my cooling system for the first time everything went really well , The engine reached 98 degrees and the fans came on great. Then I started messing about making the hoses look better. To do this I has to drain down the system. Since then I have not been able to get rid of an air lock.The engine goes past 100 degees but no fans . when you touch the area in the radiator where the sensor is for the fans its cold so is the bottom hose. My header tank and return line are higer than the highest piont on the engine. Anyone no agood way of venting this trapped air. No lavatory jokes please. Is there a set filling procedure I should be following.

28-04-01, 08:56 PM
I used to have the same problem on my dax , when i had a new 4.6 installed i took the radiator out and had a small return pipe fitted to the top of the rad on the opposite end to the top hose this i returned to the header tank with a T joint so any air is expelled into the header tank .

28-04-01, 09:05 PM
Have you got the thermostat in the correct way round ,there is a small plastic ball that will only allow water to flow in one direction when cold .Option 2 crack open the top radiator hose to allow the air to escape while filling, I welded a 10mm nut into a piece of steel pipe and fitted the corrospondin bolt to make a bleed nipple this was then fitted into the top hose and worked a treat.

28-04-01, 09:38 PM
Hi there a friend had the same problem on his dax / rover I got round it by using a 45 degree bend with a vent pipe welded in(fitted straight after the thermostat housing) and returned to the header tank.

29-04-01, 08:56 PM
I found the best way to get rid of the airlocks in my Rover powered dax is to remove the top hose from the thermostat housing when filling only reconnecting when coolant flows from the housing. I intend to fit a thumb screw air valve at the highest part of the top hose when i figure out how to make a good seal between the hose & valve, is there a manufactured valve for this purpose?

29-04-01, 09:02 PM
Thanks for the advice lads. with a bit of help well quite a lot of help from Paul the Demon welder,I was able to do just that. There is now a boss in my new top hose with a 6mm thread so I can either plug it and turn it into a bleed valve or fit a right angle fitting and run back to the header tank so that it will self vent.Thanks again and thanks to Paul for the time and effort.I think thats quite a few pints I owe you now.When its polished and fitted I,ll let you know how it works

07-08-01, 12:06 AM
The 3.9 Range Rover uses a metal heater pipe which runs along the top of the RH cylinder head. This incorporates a high-level bleed point. Andy R.