Bleeding the radiator system

[Huw Peplow]

Spent most of yesterday trying to bleed the cooling system.
Initially only one side of radiator became warm (the one with the bleed back to the header tank) Eventually by jacking the lt front side of the car up and then filling the rad via the engine bleed port on theengine return inlet housing got degree of circulation. Have put a thermostat switch in the circuit to turn the fans on and off at 90 degrees C .However the system seem to boil quite easily and the temp gauge reads 95-105 all the time.
Any advice on bleeding the system
And with the header tank at cold should there be any water in it as mine has emptied overnight or is that the air lock moving


Initially water prefered t o run round the bleed system rather than through the rad

 

[Frank Catt]

Huw, read the very recent, lengthy thread on trhis issue with the CAVS, or call for more info. Frank

 

[Neal]

You should see water in the header tank. I have a similar setup with the air line return to the header tank. I took several cycles before it fully bled all the air out.

 

[Huw Peplow]

THanks frank have just done so and it could be a similar problem.

when the rf is at rest the header tank allows the rad to self bleed down the bleed line .What happens when its running is probably that the pressure from the water pump pushes water to the rad on the same side as the bleed nipple which is of a narrow diameter.But in turn the header tank pipe fills the system on the same side just below the water pump via a 1/2 inch bore pipe.Does this mean that water fills the header tank forcing air down to the radiator as according to pipe dimensions ,pressure and distance this would be the direction of flow.Then due to expansion of fluid and gas the contents of the header tank are deposited on my garage floor.this continues when the engine is turned off.On cooling the header tank has no reserve of fluid in it

or have I just not bleed it well enough

 

[Frank Catt]

Huw, give me a call and we will talk it through !

 

[Ricky]

Hew,
This is how my system is plumbed and how I bleed it so I hope this makes sense in your application ....

The left side rad water pipe has a dash 10 hose fitted to it near the engine and connects up to the bottom of the header tank. This is the fill line.

The rad blead line goes to the top left of the rad to the header tank to allow air from the rad to bleed to the header tank. (1/4" line)

The rear of the inlet manifold has been drilled and is fitted with dash 4 lines to remove air from the rear cylinders. These connect to the thermostat housing.

The manifold outlet connects to the right side rad water pipe.

When filling and bleeding the system, set the car nose down and open the rear manifold bleed lines, the bleed line fitted at the rad end and open the heater valve. When fluid expels from the rad bleed port reconnect the bleed line. Then, keep filling but take your time. You will hear the system gurgle and burp from time to time so slowly does it.

When fluid comes out the rear manifold bleed ports close these as well.

Top off the header tank and leave for a few hours or over night with the cap off. Often the system will settle and air will bleed back during this time.

Next day, top off the header tank again and replace the cap. Start the car and warm up enough to get the thermostat open allowing coolant to circulate through the system. (The car is still nose down)

Allow to cool and check fluid level, top up if necessary. The header tank should be full or there abouts at all times. Also crack open the rear manifold bleaes and check the is no air there.

My RF runs about 80 degrees (C) and on track have seen 105C (On a 38C day)

Hope this helps.

 

[Huw Peplow]

thanks Its the rear manifold bleeds that I had not sorted as the instructions implied that these were optional .Obvious really any photos of where you drilled. Think mine has a plug either side on the inlet manifold

 

[Ricky]

My manifold had 2 bosses cast into it. These needed to be drilled out and appropriate fittings installed. You should pick these up in the attached photo.

Also the second photo shows how high I fitted the header tank. ie, well above the top of the heads

THe large braided hose is the fill line to the rad pipe, the small braided line is the bleed from the rad. The clear hose is the overflow - presently just to the ground as I have not worked out a catch tank arrangement yet.

Hope the photos help.

 

[Huw Peplow]

Ok having stripped the inlet manifold is this what has to be done

on the rear water channel inlet on photo you suggest drilling and tapping a bleed hole on both sides to connect themthen linking them to the by pass out let on the thermostat housing. this allows a bleed point as high as possible
I note roush have blocked the centre water cross over channel on the heads
Out of interest only would it not be possible to drill this area and connect it accross with just a bleed point ignoring a connection back to the thermostat housing

on photos drill point is marked with a piece of vinyl

 

[Huw Peplow]

As you can see I have no bosses on mine but will have to drill through the machined sur face to achieve the conn ections you have made

Full understand why !

ps thanks for the photos must have posted them milliseconds appart

 

[Ricky]

On my original manifold there were no bosses either. I just worked out where the rear water outlets in the heads were and then drilled through the manifold to pick up on these outlets (at right angles to the top surface of the manifold of course)

The holes were tapped to 1/8" npt and dash 4 fittings and hose fitted.

You need to take the hose forward to the thermostat so that the system constantly bleeds. If you just cross over from one head to the other you still have the potential for air to be trapped at the rear of the engine.

 

[Peter Olliviere]

Just my 2 cents on the filling of the RF cooling system. I just did this last night, completely filled and bled the system in about half and hour.

After having gone through the convoluted process of trying to bleed these systems before, I decided to try a vacume bleed system. I will never do it any other way again. The device allowed me to pull a vacume on the system at the header tank then use that vacume to pull the coolant into the system.
The process was easy, quick and I did not spill a drop, and left no air pockets.

Peter

 

[Huw Peplow]

at what point did you feed in the coolant. ?

 

[Peter Olliviere]

HUW,
If your question was ment for me, the coolant is introduced at a fitting that is part of the unit. The entire unit is mounted in the filler nect of the overflow tank, highest point in the system.

I will post some info and pictures this afternoon.

Peter

 

[Huw Peplow]

yes thanks

 

[Neal]

Gates makes a unit that is about US$100.
UView UV550000 Airlift Cooling System Leak Checker and Airlock Purge Tool Kit - Toolfetch.com

 

[Peter Olliviere]

http://www.toolfetch.com/Category--Automotive--Cooling_System--MIT4700.shtml

This is the one i use.

Peter

 

[Jim]

I note roush have blocked the centre water cross over channel on the heads

Those holes are not water passages. That is exhaust passages that go to the intake manifold. Was used to help with emissions and engine warm up when cold. Not needed in a fair weather car.

 

[Huw Peplow]

thanks The rear two however are water arent they? ? as they are about to be included in the water system

 

HUW,Yes the rear two ports are for water ( cooling ). Link them together
and connect to the thermostat housing as RICKY states
I have just filled my system and had no problems at all. I only cracked the above mentioned ports and topped up the expansion tank slowy till coolant escaped from them , then topped up the expansion tank after starting

Regards, Burns.