Draining Coolant?

[Sjmmarsh]

I have just completed a 1,000 mile round trip to Le Mans. The only issue I had was the radiator fan fuse blowing resulting in the car boiling over when I hit the stationary queues getting into Le Mans.

I topped up with water once it had cooled down and replaced the fuse, which got me home fine, albeit with mainly water in the radiator judging by the time it took to fill up.

I now need to get the water out and replace it with fresh coolant. The servicing manual says to open the drain tap, but I can't tell from the diagram where it is located. I think it is on the bottom rear LHS of the radiator as you look at it?

I have seen reference to a drain tap on the engine as well - does the V12 have one of these? (I presume not as the servicing manual only shows one tap).

Is there anything I should know before doing this (e.g. tap jamming, may have been replaced, pratfalls etc....)

BTW: Fuel consumption on the whole journey averaged 16.2mpg. Not as bad as I thought it might be given some of the AutoRoute blast on the way back. (16.7mpg on way down on D roads, 15.7mpg on AutoRoute)

Thanks!

Steve

[spanish 2+2]

Hi there, I know there's a drain tap on the 6 cylinder block as well as on the radiator, don't know about the 12 ? If the tap is seized, you may have pull off the radiator bottom-hose to empty the coolant. Usual applies to re-filling, heater set on hot, fill with coolant, run engine, press the main hoses to purge air out of system, top up as necessary.

[MarekH]

There is a drain tap on the bottom of the radiator. There isn't one on the block. The lowest point is at the oil/water heat exchanger, either the two large hoses at the sides or the heater return on the left. To purge the system of air, either park uphill or loosen one of the heater hoses when full and retighten as the air bubbles give way to water seepage.

kind regards
Marek

[Sjmmarsh]

Thanks Marek and Spanish.

The good news is I have located the rap and it works fine, so should be a simple job (unlike most things!)

Steve

[MarkE]

Steve, it's really worth cleaning the cooling system with a decent product like Forte coolant flush if your system innards are unknown. The V12 silts up very quickly apparently, and if the coolant hasn't been changed frequently (every 2 or 3 years) it's worth spending a bit to be assured that it's properly de-bunged.

It's expensive as you'll need 20% by volume of the flush, which for our cars is 4 litres, but it really does make a difference. I just flushed my XJR-s using this stuff, and a lot of scale and sandy stuff came out. ...from an engine that's only 8000 miles old and the coolant is changed every 3 years.

You'll also need 10 or 12 litres of 'antifreeze' coolant of course!

[David Oslo]

Another usefull thing to do is to back-flush, get the water flowing in the opposite direction to normal, to stir up any silt that may have deposited itself in nooks and crannies in the direction of flow.

Bit difficult to do unless the block and radiator are out of the car ( :D ) but I also like to invert things (e.g. turn upside down) as well as back-flushing.