what's the swirl tank for?

[Stopherson]

Can anyone tell me what the swirl tank does on a serpentine engine?

I'm getting slightly erratic temperatures in traffic at the moment, but the expansion tank always has the same water levels in it. The fans are OK and the thermostat seems to be working.

Although the expansion tank level is always the same the swirl tank was half full - I topped it up but problem repeated. I would have thought that the expansion tank would be the highest point in the cooling system in order to remove air locks but the swirl tank seems to be performing this function at the moment.

Is this responsible for the temperature fluctuations (abour 100deg in traffic?)

thanks

Chris

[beano500]

It's for "swirling"!

[Stopherson]

...ask a stupid question!

[beano500]

Actually, I posted that thinking that my "Bible" was near at hand and there'd bound to be something in there from SH to explain, but I have poured over Chapter 7 and not learned anything!

Apart from having this arrangement on later cars, and presumably being more efficient in some way, I have no idea!!

[ATG]

The swirl tank is largely for arguing about

I agree that air tends to collect in it for precisely the reason you point out, i.e. it is almost the highest point in the system. Try leaving "some" coolant in the expanison tank ... personally I think you don't need more than a few inches in there. Now fill the swirl pot up. Fillig the swirl pot in your case will GUARANTEE that about half a litre of air will have been expelled from the main part of your cooling system.

Have a look in the Chim forum for a recent debate on this ...

[RichB]

No the expansion tank is not the highest point in the system. The swirl tank is, and that's why it has the brass nut on it so you can bleed air out of the top of the system, having done this you should only ever need to re-fill via the expansion tank. There may also be a bleed screw on the top corner of the rad' - can't remember but if there is see if you can get any air out of here also. Sounds like you may have air in the system, so you could remove the brass nut - run the system for a few mins to churn the water around with the water pump, then top the swirl tank up and tighten the brass nut. Then see if you can get any remaining air out of the system. Finally fill the expansion tank to half way. Rich...

p.s. Or... alternatively buy Steve Heath's book! http://ourworld.compuserve.com/homepages/shpub/

[GarryM]

You might have a blockage at the bottom of the expansion tank. I had this on mine and was merrily inspecting the levels in the expansion tank completely unaware that it was in effect no longer part of the system! Crystals/corrosion can form in the coolant, in fact my expansion tank needed replacement. I will have my coolant system flushed every year from now on.

[shpub]

I was saving the swirl tank explanation for the third edition

Basically helps remove air by collecting it at the top which is why you run the engine with it open to remove an air lock.

[Stopherson]

So to remove an air lock to i run the engine with the swirl tank open, do i have the expansion tank also open?

Any ideas how to check if the expansion tank is blocked?

Much appreciated

Chris

[GarryM]

Stopherson said: So to remove an air lock to i run the engine with the swirl tank open, do i have the expansion tank also open?

Any ideas how to check if the expansion tank is blocked?

Much appreciated

Chris

Re your second question - you may be able to remove the tube attached to the bottom of the expansion tank - if coolant flows out of the expansion tank you have no problem!

[RichB]

Stopherson said: So to remove an air lock to i run the engine with the swirl tank open, do i have the expansion tank also open?

Chris yes, but it's not rocket science, all you are trying to do is churn the water around enough to disclodge any air that me be trapped in places like the heater hoses etc., oh yer' so set the heater to Hot as well. I would also make sure the expansion tank has plenty of water in it so you do not draw air in from here as you are expelling out the top! Oh and for water I mean 50/50 water/coolant mixture obviously. Oh and another trick is to loosen the top haeter hose off a little until you get water running out of it. Go and have a play, it's only water after all! Rich...

[xain]

When I tried this technique to bleed the air out, it worked the first time. The second time I did it, as the engine started to get hot (before the fans cut in) coolant began to belch out of the open swirl tank top! I decided to give up, and I can still hear air in the system (nice gurgling noise in the footwell)

Is there some knack to prevent it overflowing? When do you decide that all the air must have escaped?

[RichB]

xain said:Is there some knack to prevent it overflowing? When do you decide that all the air must have escaped?

DOn't know, never had that happen to me, but obviously the belching was the air inside trying to escape. Not much help I know but all the same, I guess you need to just let it keep belching? R...