Bleeding coolant system

[ianfletcher]

I changed the coolant last weekend and thought I'd bled the system properly because the heater was hot but as the week has gone on the blowers have cooled down especially the passenger side so it must have air trapped in the system somewhere. The coolant level has been going up over maximum too so doesn't look like I've got a leak.
When I'm bleeding it and put the heater on am I supposed to have it on re-circulate because I haven't had it set like that and I'm wondering if this is where I have been going wrong?

[Cymrudragon]

Originally Posted by ianfletcher

I changed the coolant last weekend and thought I'd bled the system properly because the heater was hot but as the week has gone on the blowers have cooled down especially the passenger side so it must have air trapped in the system somewhere. The coolant level has been going up over maximum too so doesn't look like I've got a leak.
When I'm bleeding it and put the heater on am I supposed to have it on re-circulate because I haven't had it set like that and I'm wondering if this is where I have been going wrong?

1/ Heater off

2/start engine let it warm and switch off let it cool
3/remove header tank screw and lift tank as high as poss
4/remove bleed screw and fill tank slowly
5/ water should flow in a constant stream from bleed hole
6/ fit bleed screw
7/refit tank and top it up to max
8/ take car for a spin untill hot

if you suspect air is still in the system let engine cool squeeze all visable hoses for air and repeat without lifting the tank (remember to use oats anti freeze) check heaters by pressing econ,full heat setting,and full fan, should take 3-4 mins if no heat from one heater then a blocked matrix may be a reason .

[ianfletcher]

If matrix is blocked how do I go about unblocking it and where is it?

[T-Cut]

Bleeding the heater circuit doesn't require the heater control to be off or on, hot or cold, since there's no flow valve in the coolant circuit. The cab temperature is controlled by mixing hot and cold air streams. The heater circuit is always running at full bore irrespective of the temperature setting. Another way to remove trapped air is to use the Pela pump vac filling gagetry to evacuate it. The air will be extracted by expansion.

Flushing the matrix usually involves removing it from the heater system and applying hosepipe pressure to the flow outlet. I believe it can also be purged in-situ by disconnecting the hoses under the bonnet and putting the hosepipe onto one of the flow pipes. I've never done it so can't advise further.

TC

[Cymrudragon]

Originally Posted by ianfletcher

If matrix is blocked how do I go about unblocking it and where is it?

As what TC said
The matrix is behind the ashtray area accessable by removeing drivers panel in the footwell the 2 pipes should be to hot to touch if working ok if top hose is cold/warm its blocked imho

Remove the header tank and the and hose attached to it 2/ remove the top hose on the rad, 3/ flush the top hose leading to the matrix.
4/ let it flush for a while untill water runs clear squeezing all hoses as you go to rid the pipes of deposits and slime build up 5/ reconnect all pipes and fill system set out above . if this still does not sort it then removing the matrix is the last option .

Remember to save the anti-frezze befoure you flush or as much as possable if you can . hope this helps
andrew....

[loz1971]

On my old Peugeot 406, you had to make up an "extra expansion tank" when changing the coolant due to the fact that the hoses were lower than the fitted expansion tank.

Basically, you get an old screen wash bottle or similar, cut the bottom off, and wrap tape around the neck of the bottle until it is a snug fit in the fitted expansion tank neck. Then you re-fill the car with coolant and fill the "extra" expansion tank half way. Then you run the car until the fan cuts in and your done!! you let the whole thing cool down and remove the "extra" expansion tank. Then, apparently, there are no air locks (and I certainly never had any).

Would this system not work on our cars??

[chrissyboy]

Originally Posted by ianfletcher

If matrix is blocked how do I go about unblocking it and where is it?

set heater to high,whhile refilling dont fill to quick or you will get air in the system .run engine make sure you are topped up and bleed .check that all pipes are getting hot ,and that the heater is blowing really hot . top up after each bleed ,look at gauge if air is in system the gauge wont go up to the 9 o/clock postion,bleed again , feel all hose`s and make sure both matrix hose`s are hot
top up if needed ,replace cap and then go for a little drive ,lleave car to cool or over night ,check in morning that level is right go for another drive to allow engine to reach the normal operating temp test heater again ,job is done NEVER BLEED A CAR COLD ALWAYS RUN ENGINE ..WHILST DOING THE BLEEDING .that way the air wi;ll come pout easy as the coolant is circulating .plus there is no needed to raise the header tank ,,think about it if there was they would of made the car with the tank higher

[ianfletcher]

Originally Posted by chrissyboy

set heater to high,whhile refilling dont fill to quick or you will get air in the system .run engine make sure you are topped up and bleed .check that all pipes are getting hot ,and that the heater is blowing really hot . top up after each bleed ,look at gauge if air is in system the gauge wont go up to the 9 o/clock postion,bleed again , feel all hose`s and make sure both matrix hose`s are hot
top up if needed ,replace cap and then go for a little drive ,lleave car to cool or over night ,check in morning that level is right go for another drive to allow engine to reach the normal operating temp test heater again ,job is done NEVER BLEED A CAR COLD ALWAYS RUN ENGINE ..WHILST DOING THE BLEEDING .that way the air wi;ll come pout easy as the coolant is circulating .plus there is no needed to raise the header tank ,,think about it if there was they would of made the car with the tank higher

So I need to have the bleed screw out as the car is running? And also do I undo the bleed screw so far or do I remove it from the hole all together?

[ianfletcher]

I don't understand this. Am i supposed to run the car until the coolant reaches full temperature then undo or remove the bleed screw as the car is running or should i switch the engine off first?

[chrissyboy]

Originally Posted by ianfletcher

So I need to have the bleed screw out as the car is running? And also do I undo the bleed screw so far or do I remove it from the hole all together?

yes bleed while engine is ticking over .remove the bleed srew completely from hoses .. its best if 2 people are doing it so one can listen to the air ecape and to see the flow is not stopping and starting .while the othe person can keep the heaeder tank full .