Vacuum filling coolant system

[TomL]

Last week Rae asked if I could replace the photos on this post which had been so kindly withdrawn by Photobucket. Unfortunately they were no longer on Photobucket and even after much searching I could not find them. Today I was looking for some other photos and woe and behold I find these photos so here you go.

This is how I replace the coolant in my bike. There are no doubt other ways to do it but this is the way I sorted out way back when.

To carry out jobs such as changing spark plugs and checking valve clearances, the radiator has to be removed. On our bikes it is necessary to refill the coolant using a vacuum filling system so as to remove all air locks.

The equipment that I use is a part of a Draper Cooling System Vacuum Purge and Refill Kit 09544, a Pela 6000 Spherical Oil Extractor.

The bike is placed on the side stand and the overflow hose from the coolant reservoir is blanked off (under the LH footrest) and the hose from the radiator neck is clamped off. The adaptor with the correct size rubber sealing ring is placed into the radiator neck and expanded to form a good seal.


The hose from the Pela pump is connected to the radiator adaptor, and a vacuum of 60mmHg is created in the engine cooling system.  You will find that the bottom hose will suck flat. This is about the maximum vacuum that can be achieved. The turncock valve is closed off sealing the vacuum into the engine cooling system. If all is well the vacuum should not reduce, i.e. there are no leaks.

The vacuum hose from the Pela pump is removed and the coolant suction hose is placed into the premixed coolant container and connected to the radiator adaptor. The coolant container is mounted higher than the motorcycle.

The turncock valve on the radiator adaptor is then opened and the coolant will slowly transfer from the container to the engine cooling system. As the vacuum goes down the coolant goes from the container to the motorcycle. Leave the coolant container and hose in position. There should still be sufficient coolant in the hose above the radiator adaptor to replace coolant removed when bleeding the system.

You then need to go to the other side of the motorcycle and loosen the 16mm hexagonal bleed connector. Once the air is pushed out coolant should come out and the 16mm plastic bleed valve can be tightened up.

Now the air has to be bled from the water pump bleed nipple. This can be done with the Pela extractor but I use a Mityvac. I find that I get better results if I put a layer of PTFE tape on the nipple threads before starting the job. When air bubbles no longer come out with the coolant, the bleeding is complete.

Remove the radiator adaptor and top up the radiator to the bottom of the filler neck. Refit the radiator cap and remove the hose clamp. Fill the reservoir to the correct level and refit the filler cap. Remove the reservoir overflow hose clamp. Job done.

[KTM AL]

Thank you Rae and Tom for that .

[Philip]

Yes, thanks Rae & Tom.

As they say, a picture says a thousand words.

Should get around to this job in a few weeks.

[TomL]

The bike is placed on the side stand and the overflow hose from the coolant reservoir is blanked off (under the LH footrest)

. If I remember there are three hoses that come out under the LH footrest. The one that has to be blocked off comes from the coolant reservoir neck and can be found by blowing an airline down the hole from the neck of the reservoir.

[pipwidge]

thanks for taking the time to replace the photos,,,     pictures are where i am at 

[Phmode]

Having just spent three long, arduous days trying to remove all sorts of shite from the depths of my radiator finning, I have the following comments to add to this.

Firstly, having, in a fit of petulance, read the RepROM (a first for everything), I note that they specify that the tube from the fluid container to the filling valve should be full of coolant before the work proper starts.

So, having obtained a vacuum of -9bar with my compressor and left it locked off while I made a pot of tea I confirmed that the perishing radiator was indeed not leaking as I had first thought. Of course, had I thought, I would have done a vacuum test before I removed and cleaned it, but hey ho!

Having connected up the coolant container I then cracked open the inlet valve and let the tube fill with fluid and then closed it off again and re-established the full vacuum. Then, when I opened the inlet valve there was no air in the inlet tube getting into the system. Knowing how fickle the K is about air in the head, this is well worth bearing in mind for those new to the job and indeed those of us who don't normally read the ifn manual...

It is also worth noting that despite holding a vacuum of -9bar for well over ten minutes, as soon as the radiator got hot and up to working temperature the top hose does start to leak if you happen to have forgotten to put the clamp back in place. Don't ask me how I know this. So blow is bigger than -9bar suck in this instance.

Also for those who are yet to try it, I can confirm that despite my initial doubts the G2G Foam+ as discovered by Rae, is indeed a very effective cleaner despite some folks not being convinced. It really does not like being applied to a wet radiator which is a bit of a bugger if, like me, you were soaking the radiator overnight in a tub full of water. I used my compressor to dry off the radiator as much as I could and then, once applied to both the back and front of the rad, I gave it about ten minutes to work its magic but this didn't produce much in the way of foaming action. I tried giving it a second dose on top of the first and this produced masses of foam which literally lifted the shite out of the fins and left it sitting on top of the foam. I guess that our radiators have more densely packed fins than the average domestic or commercial air-con system.

I used about 90% of the litre bottle over three days so at the going rate of about £20 off Amazon it worked out about 4% of the cost of a new rad.

I should also add that my radiator was not caked with cack in the bottom outer corners but rather it was solid in a band right up the centre of the rad. This was doubtless caused by my filling the 'ladder' up the middle with about a gazillion holes in a vain attempt to get more air through the rad. It did that but it also took about three agricultural harvests worth of mud and straw with it and they used to build houses with that...so I've now sent off for a hole remover to restore it to its OEM form.

[raesewell]

Glad my find worked for you Brian, if only you had let me know beforehand you could have borrowed my hole remover 

[richtea]

You may want to suck on these whilst you consider your options, Brian:



Image courtesy of Alamy. Who I'm sure should sell hand cream or something cosmetic.

[Capt Howdy]

The easiest way to identify the vent hose to be blocked off is that it is the biggest one of the three. It’s also a good idea to empty the coolant reservoir on the left side of the bike. I don’t see the need to attach a vacuum to the water pump bleed valve as it’s below the level of the filler cap on the radiator and the weight of coolant will push fluid through. Neither does bmw reprom say to do this. That’s not to say that it doesn’t work 😁. I also leave the filler bottle on the ladder connected to the radiator with all the taps openas this adds to the ‘head’ of water and refills any coolant lost in the bleeding process.

[Phmode]

The RepROM says to disconnect and empty the header tank but after draining down the system, mine was empty so no need.

The RepROM also says to put a bleed pipe on the water pump nipple which I did a La brake bleeding, but I'm sure it won't suck air in as again it is below the level of the fluid container.

I think this is quite a daunting task for the beginner but with the right tool (which is now ubiquitous as almost all 4 wheel vehicles need vacuum filling as their rads are lower than the cylinder heads) it is a simple task as long as you rtfm...

[Capt Howdy]

Yes with the right equipment it’s quite an easy job. Setting up takes around 15 min and the refill about 15 seconds. I think the tube on the water pump bleeder is just to stop coolant dripping onto the engine cases.

[Phmode]

Ah, well spotted, although they do say to put it in a jug of fluid, which I did, but methinks it is a little overkill.