Hi folks, quick question: What?s the best method to get rid of an air lock?
The Polo (see profile) has had an antifreeze change recently, but they didn't turn the heater control to 'hot' (thus opening the water tap to the heater matrix) and I think there is an air lock. This is because the car is running hot, but not over heating, at about 95C. If you turn the heater on, the temp will drop. After a run, the bottom of the radiator seems just to be warm.
|
It depends to some extent on the layout of the engine pay - Pug/Cit have a habit of not making the filling point the highest point in the system, which makes them awkward to bleed. Generally though, rad cap off, open the heater (note many modern cars have not tap - just a flap that regulates the hot air), open the bleed screws and fill the coolant till it comes out of the bleed screws free of air. Shut the bleed screws, then start the engine with the rad cap still off, and run it up to temperature, adding extra coolant to the system as the air comes out and the level falls - note there is usually a rush of air as the thermostat opens. Once the fan has cut in, allow it cool down, and then check the level one final time, and put the cap back on. If the bleed points are higher than the filler cap, then you need to extend the filler cap with some sort of header tank - like a plastic bottle with the bottom cut off it. If you're really having trouble, you can try opening the bleed screws when the engine is running - the water pump will boost the pressure and may force more air out - don't do this when it's hot though!
--
RichardW
Is it illogical? It must be Citroen....
|
|
|
Roberson
Doesn't sound like the typical air-lock. More likely the water-pump impellor is breaking up/coming loose and isn't circulating the coolant properly.
|
|
There is a bleed valve on the right hand side ( as you look at it) just under the black thin plastic drip cover over the fan and heater unit. This is a threaded plastic screw with a seal. Just warm the car up so the system is under pressure and open the valve 1 turn or so and bleed it until water appears. Secure screw, to not overtighen it and that should be it. The water pump on this car is metal. Regards Peter
|
Thanks for that people.
Screwloose, you nearly had my heart in my mouth there! But I thought the pump was entirely metal too.
With that little tap/valve open, will the air find its own way out or will need a bit of assistance by squeezing the radiator hoses?
Incidentally, the fan blower now only works on stage three, any suggestions about that?
Thanks again
|
Incidentally, the fan blower now only works on stage three, any suggestions about that?
Is that the highest speed? If so, then the resistor pack has failed.
|
|
Most pump impellors are plastic mouldings.
|
|
No do not open it with no pressure, air will go in. As I said run the engine awhile to pressurize the system then open the valve to let the air out. The resistor block is, from memory on the left end of the motoer, so if you carefully remoce the drip tray you will be able to get at that as well. These resistor corrode and go open cct but take a look. Regards Peter
|
I think I have the hang of the bleeding sequence, so thanks for that. The last time we had to refill the coolant, if I remember correctly, we just left the expansion cap off while the engine was running. The bleed valve on the heater matrix seems the preferred option though.
Just looked up the price for one of these resistor packs (because stage 3 is top speed DD): £25!! I?ll take a look at that or more likely, I?ll let my dad look at it. Well, he is an electrician by trade.
Much appreciated, thanks
|
|
|
|
