Bleeding coolant system

[chrissyboy]

Originally Posted by 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?

keep car running till you are happy that all air is out ,top up if needed then replace cap if all is ok the fan should take a while to kick in ,if it kicks in too early bleed again ..

[Cymrudragon]

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

I think you should re-read the haynes book.

[chrissyboy]

Originally Posted by Cymrudragon

I think you should re-read the haynes book.

and why is that ? haynes manuals are known to be wrong ,and this another point where they are wrong .. with engine running the coolant is ciculating round system ,any air in it wil be removed .. must of bleed 0ver 100 cars this way no problem what so ever .. still since my car was bleed this way i`ve had no more burst hose`s and no overheating issues and no more engine running too hot ..

[Cymrudragon]

That is not the issue he had. he stated he has no heat from one side of the heater, indicating he has a blocked heater matrix. The system has to be pressurised for bleeding to be succesfull if the system isnot pressurised you may well boil certain parts eg water pump etc and create hot spots. also damageing the pins in the thermistat which in theory should stop air from bulding up within the system in the first place. having changed,un blocked, renewed a few heater matrix following the correct bleed sequence set out in the haynes manual i found that there instructons were correct and worked.

Atempting to bleed the system when the heater is on or if the water is hot will not cure the problem with air as water contains air and will be realeased when hot which will have an adverse effect when bleeding and more so under pressurised heat

[chrissyboy]

Originally Posted by Cymrudragon

That is not the issue he had. he stated he has no heat from one side of the heater, indicating he has a blocked heater matrix. The system has to be pressurised for bleeding to be succesfull if the system isnot pressurised you may well boil certain parts eg water pump etc and create hot spots. also damageing the pins in the thermistat which in theory should stop air from bulding up within the system in the first place. having changed,un blocked, renewed a few heater matrix following the correct bleed sequence set out in the haynes manual i found that there instructons were correct and worked.

Atempting to bleed the system when the heater is on or if the water is hot will not cure the problem with air as water contains air and will be realeased when hot which will have an adverse effect when bleeding and more so under pressurised heat

it also indicates that there is an air lock stopping the flow so heater can not get heat from the hot coolant passing through the matrix ..