E38 728i M52 (single vanos)| Coolant Bleed

[Alexysc]

Dear Sifus,


Just want to ask, the other day while engine not totally cold, i opened the expansion bottle cap.

There are some pressure released and the coolant level went up.

So do I need to bleed the coolant? Would there be air trapped if like that?

Also, do we have to bleed every time topping up coolant?


Thanks!

 

[Herbert]

You need not bleed again. What you can do is early morning before starting the engine, open up the extension cap and fill up with water.

 

[moots]

i would suggest you open the expension tank cap in the mornings with a cold engine and check.there should not be any pressure and no hissing sound as you open the cap and coolant shud not rise.also if you need topping up of coolant every week,then there is a leak somewhere.have this checked out as this is an impending cooling system fault.....

 

[Alexysc]

I wait till engine cool over night and open the cap. There are still preasure released and the coolant raises above the kalt level. Preasurized, the level is below kalt. This is case of requiring bleeding? Headache...

 

[alantiong]

if this happens too often, u might have a leak somewhere

 

[Alexysc]

It's been a while and i guuess i shud report back.

it turns out the screw underneath the expansion tank which was changed during the cooling system overhaul was not fasten properly and coolant was purge out.

had the screw fastened refill coolant and bleed properly, now the coolant level stay nicely!