306 d'turbo - Bleeding the Coolant System

[MikeyMike]

Picked up a 306 d'turbo that was taking a while to get up to temperature and wasn't blowing warm air through the heater.

Changed the thermostat and bled the system using the header tank method and whilst the car seem to get up to temp more quickly, the heater only works with the header tank in place. When its removed the temperature drops.

I suspect a faulty water pump, I understand that the propellers can break. It seems that with the benefit of a header tank warm coolant is forced into the heater matrix, but that the water pump alone doesn't have the ooomph to do so.

Any other better informed theories / ideas welcome.

[Old Merc]

There are three bleed valves,n/s of rad,stat housing small allen screw,plastic cap where heater pipes go into the bulk head.Do all those in that order.With the engine hot and running you should get a "good squirt" from the allen screw one,if not its a water pump job.I`ve seen a few brake blades,don`t take chances with a water pump on that engine or you may have the cam belt fail??

[jord294]

to add to ^^^^^^^^^^^^^^

cut the bottom off a 2 litre coke bottle or similar. put a little tape around the top. place neck end of bottle snuggly in top of rad, and fill will coolant/water mix.

this way the downforce of mixture will force air out.

bleed as mentioned previous.

[MikeyMike]

jord294 said:

to add to ^^^^^^^^^^^^^^

cut the bottom off a 2 litre coke bottle or similar. put a little tape around the top. place neck end of bottle snuggly in top of rad, and fill will coolant/water mix.

this way the downforce of mixture will force air out.

bleed as mentioned previous.

Yeah thats the method I've tried 3 times now. This is the procedure I have followed:

With the engine OFF, remove radiator cap and place a 2 litre bottle in the radiator filler. It screws in firmly but then wrap in duct-tape too to try to make it air tight.

Open the three bleed screws, radiator - thermostat - above heater matrix pipes on bulkhead.

Proceed to pour coolant into the system via the 2 litre bottle, once a steady flow of coolant appears out of the lowest (radiator) bleed screw tighten. Continue to fill until coolant shows at the thermostat bleed screw, tighten. And finally the highest bleed screw on the bulkhead, again tighten when coolant flows.

Ensuring that the coolant level in the bottle remains above the highest bleed screw, start the engine and raise the revs to 2000rpm, all the while checking the coolant level in the bottle. Once the fan kicks in then turns off, shut off the engine, wait for it to cool, drain excess coolant and remove the 2 litre bottle.

What I have found attempting this process is that I cannot prevent leaks between the 2 litre bottle and the radiator filler, despite screwing it in securely and wrapping it in tape, I'm constantly having to top up the bottle.

When the 2 litre bottle is in place and the coolant level is above the highest bleed point warm toasty air flows from the heater. However, once that bottle is removed the air cools significantly.

I'm thinking that the water pump is knackered and isn't managing to pump coolant to the heater matrix. Or I am getting the process wrong somewhere. Its very frustrating!

Edited by MikeyMike on Saturday 9th February 17:26

[megamaniac]

If the water pump was knackered the engine would overheat through no circulation.The system has a water heater on the cooling system to make the heater hot quicker,it is more likely this is not working.