How do you bleed the cooling system...

...on a 4.6 vogue '00. I have an intermitent overheating problem, which im pretty sure is just down to an airlock in the cooling system, but im struggling to get the system properly bled.
I had a go on saturday, byu remoing the small pipe from the top of the rad, i had the car running and kept topping the resevoir up, after a while water started to trickle out of the pipe with air too, so i kept filling, after a while though the resevoir started spilling over and high pressure steam started coming from the top of the rad... obviously i've got something wrong here.
Could someone please advise the best method to use, thanks...

i'm not sure if there is a definative method but i usually:

blast the heater matrix with hose pipe to push any crud and air out. then i fill the system as best i can via the reservoir with the small pipe off.

i also use a ramp(piece of old tree trunk) to make the reservoir higher by driving onto ramp. dunno if that bit helps but it makes me feel better!!, also dont forget to make sure the small pipe from rad to res is clear and free of debris as this is the way air is pushed out by the system.

also once you topped up the water, when you start the car you must open the vents and stick the heater on max and hot, this allows the air to flow and will help no end with an airlock.

Hello Robin,

Air locks on the RV8 from an earlier period are dealt with thus:

Rover SD1 Tips 'n Tricks - #2 - V8 Coolant Fill without Airlocks

You may be able to adapt the process to your car. Let me know if it works.

Ramon
Vintage Model Airplane and Rover SD1 3500cc Twin Plenum Vitesse

The cooling system on a 4.6 is self bleeding as far as now, if you got trouble with air locks you will most probably find the small bore pipe from the top drivers side corner of the rad to the expansion bottle is blocked, or the expnsion bottle connection for this pipe, remove the expansion cap when the engine is running, but not hot, and you should see a constant stream of coolant running into the tank from that pipe, this is how any air in he rad vents out, if the pipe is blocked you will get a build up of air in the rad and temp will go up!!

The cooling system stat is in the bottom hose so theres always pump pressure in the rad, this is what pushes the coolant, and any air, into expansion tank.
The coolant flow through the heater matrix is constant so putting the heater to hot or cold will make no difference to the flow of coolant through the matrix when filling and venting the cooling system.

check your little pipe!!

as he said above but if you take the pipe off the rad, with engine off, you can blow down it and, obviosly, bubbles should appear in the tank.

if someone has use any coolant leak sealer it will have blocked this little water way. if so use a small drill bit to gently take out the crud.

i am having the same problems but mine started with the pump exploding and head gasket giong. had preshure cheaked and all ok. can fill it up all ways and still the same once the caps on preshure building up. changed radiaotr and thermost. one thing bottom hose is frezzing that normal?. any more help would be great.( i found so stop leak in boot when i boight car just hope its not the block

tc3636 said:

i am having the same problems but mine started with the pump exploding and head gasket giong. had preshure cheaked and all ok. can fill it up all ways and still the same once the caps on preshure building up. changed radiaotr and thermost. one thing bottom hose is frezzing that normal?. any more help would be great.( i found so stop leak in boot when i boight car just hope its not the block

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From the norwegian LR forum I have read many articles about these issues. I have also spoeken to an LR mechanic, and sorry to say, but in most circumstances the block is gone..

Rover V8 cracking block and all the theories around - LR4x4 - The Land Rover Forum