Bleeding Coolant

james250 · January 24, 2014

A while back I was looking at how to bleed air from the coolant system on the IS250. Most people on Clublexus recommend to start the car cold with the pressure cap removed and that apparently the air will bubble and burp out. Problem is when i tried this, as soon as i started the car the coolant started overflowing and getting pumped out. Has anyone tried this method? i'm worried that if people are doing this without problem then that means something is wrong on my car. Someone suggested it may be sign of bad head gasket?

Any ideas?

Thanks

james250 · January 24, 2014

From what i've read so far, with the pressure cap off and starting the car cold. there should not be any pressure as the system is not pressurised. so if coolant is overflowing then pressure is probably being generated from leaks in the cylinder head or something. I'm concerned that there may be some sort of leak in the head gasket.

I've come across the Holts Radweld product: http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_743657_langId_-1_categoryId_255217

anyone used this product? wondering if its worth using to prevent problems?

Lillywhites · January 25, 2014

Have a look at k-seal it's not cheap but all the mechanics swear by it part number 542770100 put that in the search box on euro carparts web site

ChumpusRex · January 27, 2014

One way to bleed without making a mess is to use a zero pressure radiator cap.

Buy a cheap radiator cap that fits, and rip off the springy valve mechanism. This will put the radiator in direct communication with the overflow bottle. Any air will bleed out under zero pressure. You can then squeeze and massage the hoses to bleed it out, with fresh coolant being sucked in from the bottle.

Allow to come up to temperature to make sure that all air has been expelled. Shut off and allow to cool. Reinstall the normal pressure cap once done.

koppatroppa2002 · February 13, 2014

Get cold air on pasanger side and not very hot on driver side even though I set to high temp as v cold those days!! Checked coolant level and its ok pink ascshould and no smell :-d I hear sometimes when cold start some gurgle noise wich show some air stuck inside ...I heard. .. any thoughts much appreciated.

Is220d 2008 84k

james250 · April 7, 2014

One way to bleed without making a mess is to use a zero pressure radiator cap.

Buy a cheap radiator cap that fits, and rip off the springy valve mechanism. This will put the radiator in direct communication with the overflow bottle. Any air will bleed out under zero pressure. You can then squeeze and massage the hoses to bleed it out, with fresh coolant being sucked in from the bottle.

Allow to come up to temperature to make sure that all air has been expelled. Shut off and allow to cool. Reinstall the normal pressure cap once done.

Thanks Mark,

Any idea what size cap will fit? Looking on eBay and there are soo many which are nice and cheap. Not sure if they will fit.