Hi all - I'm no Disco expert like some of you, but pretty handy. 2004 Discovery 2 help needed!

The bottom plastic connection point on my coolant reservoir expansion tank snapped off and coolant was pissing everywhere when I parked it. Replacing the tank itself looks straightforward, part should be arriving in a day or two - what has me a little stressed is the bleeding of the system. Any step-by-step instructions on how to do this effectively? Is it 100% mandatory to do it when replacing the tank?

Any advice is much appreciated!

 

Yes you need to bleed it. I’m not going to try to remember the sequence but it’s not difficult. The LR Workshop manual is very good. If you search for a thread on this forum from WaltNYC, he has links in his signature to all the manuals.

 

There are million ways to skin the cat when it comes to the bleeding the cooling system. They all work in one way or another. The RAVE has a good- albeit a bit difficult- process.

But the main thing to accept is it probably won’t get fully bled in one shot. It usually takes me a few days to get all the bubbles out (I just did the water pump in mine, and I’m on day 2 of bleeding). You’ll get most of the way there the first time, but just expect to have a few more bubbles to get out over the next few days.

 

Got it. So the basic steps from what I can read are: connect all hoses to new tank, have new tank propped up 6-10 inches above the engine for gravity to do its thing, remove the bleeder valve screw completely, slowly fill until it starts oozing out the open bleeder valve, replace valve screw and fill the rest of the way

I guess my main hangup is if it's not completely 100% bled, like you mentioned, am I still able to drive the car without issue? How do you know there's more bubbles to get out & how do you get them out?

 

I’ve only ever done the procedure once (per time of breaking into the cooling system) and have gotten away with it.

 

Heres a good alternative/upgrade for the stock expansion tank

Amazon

Amazon

OEM part number 17111712641

The hose from bottom is 45 degree angle on stock and this BMW one has 90 degree angle, it will fit, but will be tight with the fusebox wires.

With a coolant level sensor

Amazon

Amazon

EAN 3800946661740

Sorry for the .de amazon links You should be able to get it elsewhere too.

I'm not 110% sure it will fit V8, but should?

Just put one up on my TD5 and will order a one for the V8 too.

 

I have an 03. Bleeding the stock set up is pretty much what you posted. Then bleed it again when the system is cold. I used to bleed mine with the front slightly raised up using the upward slope of our drive way.

I never had excessive air in my system from an expansion tank swap with the stock set up.




These days have an inline thermostat on mine. No additional bleeding needed for a expansion tank swap. Just did that two days ago.

 

Sigh.

There are SO MANY crazy stories and methods out there about bleeding the DII cooling system. I have ALWAYS been successful following the procedure in the RAVE. I have NEVER had a problem doing it that way.

It works.

Follow it.

No need to hang your Rover from a tree, a la "The Gods Must be Crazy".

The link to the RAVE is in my signature and also below. See the instructions on p.429 of the 1529 page PDF. It's that easy. That's all it takes.

http://l.b5z.net/i/u/6064257/f/D2_Workshop_Manual.pdf

 

Since the bleeder screw is at the highest position and air gets trapped in highest hoses.... I do this...

1) remove old tank keeping all loose hoses as high as possible. replace with new tank.

2) fill new tank to appropriate level. fill the top hoses through bleeder screw (small funnel...usually it takes +/- liter through the bleeder..) until overflowing. replace bleeder screw. replace tank cap

run the engine for about 30 seconds

3) repeat 2 until no more air comes out of bleeder. then 4.

4) run the engine until up to temp for 10 min (at least until thermostat opens)

turn off, let cool completely and check bleeder and refill at bleeder as needed....

check bleeder again after driving.......

Never had an issue this way with stock cooling system.....I have replaced the bleeder with a brass screw making this easier. Don't strip the bleeder screw or housing.

probably the cheapest and best value part from RN:
https://www.roversnorth.com/parts/pl...lastic_tee_dii

 

Inline thermostat mod and your bleeding woes are over.