Tigercatkid
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 posted on 1/10/16 at 01:34 PM |
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Expansion tank woes
Hi
Just changed my rad to an alloy one and now have continous problem with my expansion tank over flowing after most runs. There does not seem to be much
coolant in the top exit from the thermostat housing (main hose to the top of the rad). I'm guessing that the thermostat may be stuck or not
operating properly and forcing coolant up into the expansion tank.... even today after a week sat idle, I opened the cap on the expansion tank and
about 0.5 pints of coolant spurted out.
Any other suggestions as to what's going on?
It's a 2.0L zetec engined Tiger (new water pump at rebuild two years back). Was running perfectly until I changed over to the alloy rad.
Suggestions very welcomed !
Tiger CAT E1
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benchmark51
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| posted on 1/10/16 at 02:09 PM |
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I would say you have an air lock. Is the new rad sat vertically and does it have a filler cap on it? Are you sure there isn't a space at the top
of the rad that is holding air? If it has a filler cap is it at an adequate pressure for your system? Thermostats can fail but I think that nowadays
they fail in the open position( may be wrong there). When you fill the system with coolant, is the car in a significant 'nose up' position
preventing air bleeding to the expansion tank? Have you tried holding the expansion tank up high to help it bleed air out?
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Smoking Frog
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| posted on 1/10/16 at 02:10 PM |
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Radiator partially blocked? Hose though rad and check flow.
Air lock? Drain and refill. Leave a vent somewhere in the system while filling.
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Tigercatkid
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| posted on 1/10/16 at 03:09 PM |
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Thanks for that... airlock also crossed my mind.
The rad does not have a cap but does have a bleed screw at the very top front edge.
I have tried pressurising the expansion tank until coolant comes from that bleed screw... almost emptying the expansion tank. Then topping up a
little. The system then seemed to be full - top hose to rad full up (you can hear coolant moving when you squeeze the hose).
Went for a run and after about 30 mins, fluid starts coming out of the expansion tank and little coolant in the top hose again...
Tiger CAT E1
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daviep
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| posted on 1/10/16 at 06:13 PM |
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Just curious but what prompted you to change you radiator?
Regards
Davie
“A truly great library contains something in it to offend everyone.”
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Tigercatkid
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| posted on 2/10/16 at 09:01 AM |
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Old rad was full of holes and 15 years old... so time to stop patching it up and get a new one.
Tiger CAT E1
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coozer
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| posted on 2/10/16 at 11:29 AM |
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Where is the coolant tank plumbed into?
1972 V8 Jago
1980 Z750
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CosKev3
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| posted on 2/10/16 at 11:52 AM |
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So the new rad was a exact swap over,same pipe connections etc?
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britishtrident
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| posted on 2/10/16 at 01:54 PM |
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A couple of pictures of the system would help.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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Tigercatkid
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| posted on 2/10/16 at 03:56 PM |
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The new rad is a like-for-like swap for the old one - same size, connections etc.
Today I have again released the bleed screw and pressurised the expansion tank - I manged to almost empty the expansion tank before coolant peed out
the bleed screw hole. I also removed the bleed screw whilst the engine was running at temp... and got an 8 foot jet of hot coolant out !I have
tightened the bleed screw and put about 1 pint of coolant into the expansion tank and gone for a 20min run. Thus far no dramas...
I just cant fathom what the issue was / is... I come back to an airlock...
Tiger CAT E1
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britishtrident
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| posted on 2/10/16 at 04:29 PM |
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Questions:
(1) How is the tank connected?
(2) When the old rad was leaking did you use rad weld or a similar product?
(3) You using the proper OEM thermostat housing not water rail (aka hotter rail).
[Edited on 2/10/16 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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Tigercatkid
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| posted on 2/10/16 at 04:41 PM |
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Hi,
Not sure I follow you -sorry.
Tank is connected via main bottom hose to the base connection on the rad. The "overflow" from the top of the thermostat is connected to
the top inlet on the tank.
I did use rad weld on the system prior to swapping to the new rad... but I did not reuse the existing coolant mix... all new... you thinking this has
gunged up my thermostat or something else?
Yes, I am using a new Ford thermostat and plastic housing - I replaced it when I rebuilt the engine.
I was checking the temperature of the plastic body of the thermostat today and when it reached around 75-80 deg C, the main top coolant hose from the
thermostat housing to the top of the rad, began to get very hot as the thermostat opened... so I would say this appears to be operating...
Any ideas ?
[Edited on 2/10/16 by Tigercatkid]
[Edited on 2/10/16 by Tigercatkid]
Tiger CAT E1
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coozer
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| posted on 3/10/16 at 03:42 PM |
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Head gasket?
1972 V8 Jago
1980 Z750
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Tigercatkid
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| posted on 3/10/16 at 04:46 PM |
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Hi,
No oil in the expansion tank and a new head gasket within last 2000 miles.
Tiger CAT E1
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Oddified
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| posted on 3/10/16 at 10:24 PM |
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quote:
Originally posted by Tigercatkid
Hi,
No oil in the expansion tank and a new head gasket within last 2000 miles.
In my experience, the first signs of a head gasket problem is over pressurised coolant system/blowing coolant out and is more common than mixing
oil-water.
Of course the first checks would be double/triple checking there's no air locks/bleed problems.
Ian
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britishtrident
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| posted on 4/10/16 at 06:31 AM |
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No 100 percent sure way of diagnosing a head gasket or cracked liner unless it is gone in a truly major way. Testing for combustion gasses in the
air building up in the cooling system is the best test available. But this is an odd one as I understand the layout air the radiator should
automatically bleed back to the tank.
One thing that will work is to use a Tee to connect the bottom of the tank to the bleeder on the top of the rad. This may or may not cure the gas
build up but the gas will be in the tank not the rad.
[Edited on 4/10/16 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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Schrodinger
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| posted on 4/10/16 at 08:30 AM |
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What have you done with the bypass exit on the thermostat housing? It would normally go to a heater and then back into the rad feed, it should not be
blocked off. It would be helpful if you could put up a diagram of how you have it plumbed in or a picture.
[Edited on 4/10/16 by Schrodinger]
Keith
Aviemore
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scimjim
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| posted on 4/10/16 at 10:17 AM |
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If it's a plastic expansion tank, check the bypass pipe stub (the one that goes to the stat) - common problem on small scimitars with a Ford
expansion tank is the steel reinforcement in the stub corrodes and eventually blocks the flow, causing these exact symptoms (solved by running a drill
down the stub).
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Tigercatkid
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| posted on 4/10/16 at 05:40 PM |
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It's a relatively new rebuild (2 years - only about 3000 miles) using a new thermostat and housing.
As I mentioned this issue has only come about since I swapped rads... Ran perfectly with no issues before so it's really got me.
I will post a diagram of the system once I'm back home - I tried at the weekend but could not see the photo upload icon - give us a clue ?
Tiger CAT E1
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