chrisf
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| posted on 15/9/05 at 11:30 PM |
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Cooling system Bleeding
Gents:
I tried to follow the instructions here, but something isn't right. I feel
the cooling pips get hot and can feel the rad get hot. The fan, however, never kicks on. Now, I assume that 1.) I have air in the system or 2.)
I'm doing this wrong or 3.) both. Any ideas? What did you guys do to bleed the system?
Also, I'm using a VAG header tank with a sensor hole right down the middle. This is not fitted. Is this causing the problem? Does a cooling
system need to be air tight?
Of course this would be much easier if my water temp gauge worked but that is another post for another day.
I'm at my wits' end, so any help is appreciated.
--Thanks, Chris
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mike-ktm
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| posted on 15/9/05 at 11:39 PM |
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Chris, system does need to be sealed as it should become pressurized. fan noy kicking in because its never reaching temp. by the sound of it. Pretty
sure i' right in saying this, but if not someone will correct me very soon i'm sure.
hope this helps,
Mike
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ayoungman
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| posted on 16/9/05 at 07:43 AM |
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If rad is hot top and bottom, and you let the engine tickover for ten minutes, the fan should turn on. 86 degrees is usually the point.
Have you checked that power is reaching the fan ? Have you shorted across the temperature sensor ? This should turn the fan on.
It could be an airlock next to the sensor but this is unlikely.
"just like that !"
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Hasse
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| posted on 16/9/05 at 07:50 AM |
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Correct me if I´m wrong, but I think the reason for pressurising the system is to achieve a boiling temop above 100°C.
If you have a thermostat with low opening temp. and cooling fan kicking in early, meaning you have a good margin to boiling, you do not need to have
the system pressurised.
My system is not sealed, and it seems to work.
During driving I have 80-84°C, cooling fan starting at 87°C, reaching about 90°C on long idling and about 95°C minutes after engine stop.
/Hasse
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zetec
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| posted on 16/9/05 at 08:31 AM |
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As said get the fan circuit checked first. You would be surprised how long it takes an engine to get to the temp needed when it is at idle, especially
if there is no bonnet as the heat generated may be not enough to get the fan to start if the surface area of the rad/engine and pipes is large. Try
and get the temp guage sorted or failing that how about a kitchen cooking thermometer rigged up somehow.
" I only registered to look at the pictures, now I'm stuck with this username for the rest of my life!"
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chrisf
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| posted on 16/9/05 at 01:11 PM |
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Yep, the fan works when I unplug the fan switch and short it. I connot remember completely, but I seem to think the fan switch is rated around 97C or
thereabouts.
I played around with the car abit more after I made my post. It turns out, the cap on the header tank was not completely sealed. When I realized this,
I seal the cap and shut the engine down shortly thereafter. Them water began seeping from the sensor hole. Here's a picture of my cooling system
and header tank.
Am I doing the engine bleeding procedure properly? Is the only way to test fan kick on by sealing the header tank completly? The thread I posted
initially suggested that I should keep the system unpressured and the fan will kick on... Any suggestions?
--Thanks, Chris
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TimC
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| posted on 16/9/05 at 01:28 PM |
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Right - had a similar situation with my car. Temp measured at thermostat housing ex engine reads high. Fan controlled by switch at the out end of
the rad i.e. once water is cooled.
Hence, even if your guage worked and was high, the fan may never turn on - or at least not for a long time.
Key things for me were to minimise difference between engine and ex-rad by ensuring that oil cooler and water pipes are not getting a good warming
from radiant heat i.e. wrap your header and thermosleeve your pipework.
That should help.
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tadltd
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| posted on 16/9/05 at 01:38 PM |
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You're trying to run a pressurised system with an 'un-pressurised' radiator.
The radiator you have should be used in conjuction with an expansion bottle, which is at atmospheric pressure - same as most Japanese car and bike
set-ups. In this system, when the coolant expands, it is ejected past the radiator cap, into the expansion bottle. This expansion bottle does not use
a pressurised cap. As the system cools, the coolant is sucked back into the system.
A pressurised system uses a 'degas bottle' which expels air (gas) as the coolant get's hotter. This allows the coolant volume to
remain (almost) the same, unless you have an overheat situation.
You need to do one of 2 things:
1. Swap your radiator for a 'pressurised' system radiator, like that in most European cars (VW, Ford)
2. Swap your bottle for an expansion bottle as found in most Japanese cars (Toyota, Nissan, etc.) - the cheaper option.
Bear in mind that coolant volumes are carefully calculated so that at max' temperature there's enough volume in the expansion bottle to
cope with the expelled coolant. I therefore wouldn't use an expansion bottle from a 'bike...
You need to connect the hose from the cap into the expansion bottle.
[Edited on 16/9/05 by tadltd]
Best Regards,
Steve.
www.turnerautosport.com
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chrisf
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| posted on 16/9/05 at 01:58 PM |
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Thanks for the reply.
I have to admit to being a bit confused as to the pressurized / not pressurized system. My rad is from a Honda Civic and has a .9 bar radiator cap.
Does this make any difference at all? Would it help to block off the bleed nipple on the rad?
Or am I completely misunderstanding this and need to get a new expansion bottle?
--Thanks, Chris
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Bob C
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| posted on 16/9/05 at 02:26 PM |
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97 sounds high to me (though I'm no expert). I'd say if the water in the top hose is at 97 it'll be boiling merrily somewhere inside
the engine! I would expect a suitable switching temperature would to be slightly over the temp at which the stat is fully open, (and be nearer 90).
Just an unfounded opinion you understand.....
cheers
Bob
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tadltd
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| posted on 16/9/05 at 03:59 PM |
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ChrisF,
The 1st thing you need to do is stop f*cking around with your current system.
You then need to make a decision:
1. Buy a 'pressurised' radiator (i.e. one without a cap)
2. Buy an expansion bottle
Looking at your system, I would suggest the easiest, and quickest fix is to get an expansion bottle. So get down the scrappie, find the nearest
Nissan/Toyota/Honda/Hyundai/whatever and get expansion bottle off it, fix it in place of your current 'de-gas' bottle (it doesn't
actually have to be as high up), and cooling issue solved.
You can then concentrate on getting the fan to work at the correct temperature.
Best Regards,
Steve.
www.turnerautosport.com
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chrisf
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| posted on 16/9/05 at 05:12 PM |
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I see. Thanks for the gentle suggestion  . So I'm looking for something like
this
or
thi
s? I like this one from a
Jeep
. Would this work?
--Chris
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mad-butcher
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| posted on 16/9/05 at 07:00 PM |
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forgive my ignorance in this, but could you not just remove the radiator filler cap and have a plate soldered on the top therefore sealing the
radiator but still allowing the overflow into header tank. after all thats all an mk rad is but they completly remove the filler cap and solder a 10mm
overflow pipe in
tony
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chrisf
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| posted on 16/9/05 at 08:10 PM |
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OK, after looking under many coworkers’ hoods, I now understand what Steve is saying. I now feel a bit dumb about this. Many thanks for setting me
straight.
--Chris
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tadltd
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| posted on 17/9/05 at 01:48 AM |
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Hi Chris - sorry 'bout the heavy 'nudge', but as you were at your "wits end" I thought maybe you needed a moment of
clarity...
..any of those bottles in your links will do, as long as they have enough capacity for the expanded coolant volume.
BTW - I didn't notice you were in Texas, so for 'scrappie' read: 'wreckers yard'! 
[Edited on 17/9/05 by tadltd]
Best Regards,
Steve.
www.turnerautosport.com
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