Mon Jan 21, 2008 10:46 am
Before you start, make sure you can open and close the air vent screw on the top of the thermostat housing.
Drain the rad by pulling off the bottom hose or unscrewing the drain valve. Good idea to take the top hose and vent hose off as well, pull out the two fixings for the top of the fan shroud, unscrew the two large self tappers that hold the rad top, and lift the rad out.
Backflush it from bottom to top and wash the matrix out from back to front as well. Don't go too mad with the pressure, or all the fins on the core will bend over or worse.
Good time now to check out the distributor cap and rotor, and copper grease up the cap bolts, or even to fit a new cam belt.
There is a drain plug (19mm) for the block hidden near the back of the engine under the exhaust manifold. Don't expect to have skin still on your knuckles if you undo this.
As an alternative, disconnect the header tank and connect the hose to your hosepipe, so that you thoroughly flush out the block with clean water.
Bear in mind that the old coolant should be properly disposed of.
Stick it all back together, turn the heater control to full hot, and a) if you drained the block, fill the system with a 40% mix of good quality antifreeze and water, or b) Pour in four litres of concentrated antifreeze, first and then top up with water.
Open the bleed valve on the thermostat untill all the air bubbles come out, close it again and knead all the rubber hoses at the front to shift all the air you can.
Helps if the front of the car is slightly higher than the back.
Keep the header tank topped up with 40% mix, and open the bleed valve again.
Put the radiator cap back on and start the engine. Keep a look out for leaks, put most importantly, put the heater blower on about 2, with the heat control full on and the lower lever to the right. As the car warms up, watch the temp gauge, and check that noticeablt warmed air is coming from the heater after about a minute or so.
Before things get too hot, take off the rad cap again, and check and top up the level again.
If the heater gets hot, then all is well, but if it doesn't and the gauge begins to climb past where it should, then you have an airlock, which can potentially crack the head.
To get rid of this airlock, let things cool so that you can remove the rad cap, and fill the header tank right up. Unscrew the jubilee clip fixing the top heater hose where it goes through the bulkhead, and pull the hose off. Coolant and hopefully air will come out. Let a cupfull or so of coolant out and fix the hose back on. Check the coolant level, put the rad cap back on and try again for output from the heater.
After a while, and after the car is cool again, try the bleed screw again.
You will probably find that it takes about a week fo all the air to come out, and the coolant level to stop dropping.
Finally, if your radiator cap has a black plastic disc on the bottom, rather than a yellow one, take your VIN down to the dealer, and ask for a free new one.
Found this using the search function, the zone is really helpful as is the search function. Been using the site for a while lurking and researching its all good.
