air in cooling system

Each time i run my car i must purge the air in the front radiator. Does someone get this also ?

Fred,

If you have not already got one, run a small bore hose from as high up the radiator as possible back to the top of the header tank.
This will allow the air to bleed to the header tank and out of the system.

Brian.

Fred, I installed a new 4-core radiator and the system was still overheating. I considered using a bleed valve, but you have to check/bleed it constantly as you have found. I installed a bleed line (as previously suggested on the forum) from the top of the radiator to the header tank and this cured the system. I also have one from the top of the manifold.

Thanks for your help guys, that means you must re fill your cooling tank oftenly i suppose ?

Fred, if you run a overflow line from your header to a reservoir it should pull back liquid as the system cools and keep it topped right up. Of course the line must feed into the the bottom of the reservoir; the reservoir should be vented to allow vapor to escape from the header tank also, but hold any liquid.

I learned this tip from a Pantera web site ( apparently it was the official Pantera procedure when the cars were new). I did it when I first started up my car and it seemed to work. Jack up the rear of as high as possible, remove the radiator/overflow cap and run the car. Make sure that the thermostat opens up. This should help purge the air out of the system. Also, are you sure you don't have a slow leak somewhee? If it's slow enough and in the right place the coolant could never hit the ground. For instance somewhere high up on the radiator. The coolant could boil off.

Stig

Another cooling system tip:
I have not tried thisd myself (yet) but it does make sense when you think about it...

STEAM: steam must be controlled by adding a restrictor at or near the ENTRANCE to the radiator.

Use a washer with a 3/4 inch ID for V8 engines.

The restriction causes the waterpump to pressurize the tube going to the radiator so the hot coolant will not "flash" to steam until it reaches the radiator, where it can condense.


I got this tip from Kennedy Engineering, with one of their engine/trans axle adapter kits. They included a tip sheet for keeping mid engined cars cool. A coupl e of things stressed on the sheet was keeping the air bled out of the system via a line from the rad to the surge tank,,,and preventing steam (air) from originating to start with.

I hope this helps.

On my project,,, I am planning on using one of the Davies/Craig elec water pump systems, and gutting my stock mechanical pump (& eliminating the stock thermostat).

Fred

How often have you had to do this. There should only be a finite amount of air in the system which continual bleeding should eventually get rid of.

If the amount of air seems to be growing in the system you may have a blown head gasket and the "air" may be exhaust. This is a worst case scenario however a compression check may be wise.

John

I go with John's thoughts, Fred. You should not have to have a bleed pipe from the rad to the header tank. Some guys put a bleed pipe from the rear of the intake manifold back to the header tank but I have run ok without one of these too.

On the 302 the standard GTD has two pipes back to the header tank. From the highest point on the engine water system there is a pipe to the top of the header tank to allow air out. Then there is a pipe from the bottom of the header tank to the water pipe leading from the engine to the rad. This is how the water system is filled. Early GTDs did not have this second pipe but just the first.

Malcolm

Malcolm

As the original 40's fitted a bleed from the radiator to the header tank then it's good enough for me.

Brian.

Ferraris do the reverse of the Pantera trick - raise the nose then get to temperature and bleed - this should ensure all the air in the system is at the top of the radiator and hence bled out

I agree with ALL of you because in my experience NO two cars ever run identically. Running a single SMALL bore pipe from top of radiator to the header tank certainly improved my efficiency and i thrash my 302 powered 40 to the absolute limit in racing here in the UK.
Regards,
GTA.