a foolproof method of filling the TD5 with coolant? I can't manage to avoid airlocks.

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Stanleysteamer

Stanleysteamer

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As it says really , I am on my third or 4th attempt to do this before towing a trailer with a car on it 600 odd miles, including some very steep mountain roads.
The only thing I have yet to try is filling it really slowly.
I lift the expansion tank as I should, the coolant flows out of the bleed hole, I finish it off and put the tank back in place, but every time I get it good and hot, then let it cool and top it up, it ends up much too low the next time I drive it.
I am sure it is an airlock as before I changed the pump I didn't have this problem.
Any help, please would be most appreciated.
Thanks in advance.
Stan
 
If the level was low the first few times after driving it following a coolant fill, I would assume that an airlock had partially cleared and top it up. If after a while it stays level, fine. But if it were low again consistently I would start looking for a leak, starting with the expansion cap and the overflow.
 
Stanleysteamer said:
As it says really , I am on my third or 4th attempt to do this before towing a trailer with a car on it 600 odd miles, including some very steep mountain roads.
The only thing I have yet to try is filling it really slowly.
I lift the expansion tank as I should, the coolant flows out of the bleed hole, I finish it off and put the tank back in place, but every time I get it good and hot, then let it cool and top it up, it ends up much too low the next time I drive it.
I am sure it is an airlock as before I changed the pump I didn't have this problem.
Any help, please would be most appreciated.
Thanks in advance.
Stan
Click to expand...
I've drained and refilled mine about 3 times and have followed the procedure you have, then taken it for a 10 minute drive, after which the level has dropped, but while still warm, so there is still pressure in the system, I've slowly and carefully released the bleed screw until what has always been "foam" then coolant flows and retighten the screw and top up when cool. It may have needed a small top up after a week or so, but not much.

If the level continues to drop, either the coolant is replacing "air", or it is escaping somewhere and I'm sure you have checked for any other leaks as Si Click has mentioned.

Just my 2p worth.

Alternatively, you could put the Disco on the trailer and tow it with the Pluriel;););););););)
 
A trick i found based on the systems's description and worked every time well for me is that after you filled it with the tank raised and got coolant through the bleed hole, refit just partially the bleed screw as to still get some flow, start the engine and keep the throttle to 2000 rpm constantly untill no bubbles are coming out then tighten the screw, refit the tank, top up if necessary and tighten the tank's cap to maximum allowed, that's important as well

the explanation is that the mechanical bypass flow valve of the thermostat opens only at 1500 rpm so without opening that there is still air left in the circuit :

Bypass valve.jpg
 
I have found in the past that that any air lock in the heater matrix, so I remove the heater return pipe at the bulk head it should be the one closest to the driver’s side, then add about 18in of hose, and a funnel then lift up the end of the hose you have removed about 6 in lower than the pipe you fitted, they should then be the highest point remover the expansion tank top, and then fill up the system, when you get the expansion tank full put the top back on, continue to fill until the coolant starts to come out of the lower hose, at that point stop filling and refit the heater hose back in its original position, you will lose a small amount of coolant, finally run the engine and open the bleed screw as it warm up
 
sierrafery said:
A trick i found based on the systems's description and worked every time well for me is that after you filled it with the tank raised and got coolant through the bleed hole, refit just partially the bleed screw as to still get some flow, start the engine and keep the throttle to 2000 rpm constantly untill no bubbles are coming out then tighten the screw, refit the tank, top up if necessary and tighten the tank's cap to maximum allowed, that's important as well

the explanation is that the mechanical bypass flow valve of the thermostat opens only at 1500 rpm so without opening that there is still air left in the circuit :

View attachment 266220
Click to expand...

Cheers mate.
now you mention it I seem to remember you helping soemmee else out with this and talking about the need to rev it up a bit.
By pure chance I did that this morning before heading out on a journey of 45 minutes in fairly heavy traffic, then attaching a car trailer with a car on it then returning.
I looked as soon as we returned and it looked better. So I hope I am getting there.
Thanks for this. I will persevere.
 
Si Click said:
If the level was low the first few times after driving it following a coolant fill, I would assume that an airlock had partially cleared and top it up. If after a while it stays level, fine. But if it were low again consistently I would start looking for a leak, starting with the expansion cap and the overflow.
Click to expand...
Thanks mate, I think it is getting better and a run at normal roads speeds while towing a car on a trailer should, hopefully push the air out. It is better after I topped it up again and revved it up for a while this a.m. then picked up the car and trailer to drive it back home 45 mins with a few hills and lots of heavy traffic.
 
Well it is some hours since we returned and although the engine isn't completely cool, the coolant level in the expansion tank is bang on the level.
So I am confident I am getting on top of it, now. ;)
Thanks for all your help.:):):)
 
Hi Stan, glad you've got it sorted. Since I got mine in June 20 I've drained the coolant on several occasions & never had a problem with air locks.
My drive slopes so I park across it (like having the O/S wheels up on the verge). I trickle coolant in (bleed screw open) avoiding ANY level in the expansion tank to trap air, it might take me half hour or so (the longer the better I suppose;)) tinkering with other stuff (like there's nothing else to do on a LR:)), drink beer or tea in between each litre. When the expansion tank eventually starts to fill I then squeeze all the hoses starting at the lowest until I'm happy I've done all I can. I then start the engine with the expansion cap off & heater valves open (but no blower) until hot coolant is returning to the tank top it up, take it for a spin with the heater still on. When it's cold top up & job done. Tedious it may be but I've always taken my time filling cooling systems.
 
Andy Warren said:
Hi Stan, glad you've got it sorted. Since I got mine in June 20 I've drained the coolant on several occasions & never had a problem with air locks.
My drive slopes so I park across it (like having the O/S wheels up on the verge). I trickle coolant in (bleed screw open) avoiding ANY level in the expansion tank to trap air, it might take me half hour or so (the longer the better I suppose;)) tinkering with other stuff (like there's nothing else to do on a LR:)), drink beer or tea in between each litre. When the expansion tank eventually starts to fill I then squeeze all the hoses starting at the lowest until I'm happy I've done all I can. I then start the engine with the expansion cap off & heater valves open (but no blower) until hot coolant is returning to the tank top it up, take it for a spin with the heater still on. When it's cold top up & job done. Tedious it may be but I've always taken my time filling cooling systems.
Click to expand...
It is so good to hear everybodies' ideas. For instance @sierrafery 's thing about the necessity to rev it over 1500 rpm to get the system to open up properly. That sure isn't, in the Haynes or RAVE! I too squeezed the pipes I could get at.
I'm not sure about this but I don't think there is a conventional, i.e. old fashioned, heater valve , I think it's all done with flaps and the fan. But the more you make the system work the more likely I think it is to pump the water round and the air out. So I sure made sure the heater controls were set to "hot" and the fan was on! I like the way you do it, time consuming though it may seem!
 
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