What have I missed? Rad swap, new switch - fan now not kicking in

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GTXTRA
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What have I missed? Rad swap, new switch - fan now not kicking in

Post by GTXTRA » Sat Feb 24, 2018 4:42 pm

As per my Mk1 project thread.

Have fitted a new radiator - done this sort of thing many times including on this very car a week ago...

However - today there's an issue with the fan not kicking in when bleeding the system...

Fan works with the switch wires engaged together.

I've tried with the new switch and even the old one - the temp gauge shoots up and coolant flows out - no warning light, no fan.


What have I missed folks?


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mr.brown
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Re: What have I missed? Rad swap, new switch - fan now not kicking in

Post by mr.brown » Sat Feb 24, 2018 5:36 pm

Exactly what happened to me. It turns out I didn't run it long enough with the cap off and it must caused an airlock at/near the switch. I ran it for an few minutes with the cap off and all was well.



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james butler
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Re: What have I missed? Rad swap, new switch - fan now not kicking in

Post by james butler » Sat Feb 24, 2018 7:22 pm

mr.brown wrote:Exactly what happened to me. It turns out I didn't run it long enough with the cap off and it must caused an airlock at/near the switch. I ran it for an few minutes with the cap off and all was well.
this is why after a coolant change i always run the car up to temp untill the fan cuts in with the cap off.
still yet to work out why it causes the strangest of issues if you dont do it.


I dont mind project cars but I HATE SANDING!!!

GTXTRA
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Re: What have I missed? Rad swap, new switch - fan now not kicking in

Post by GTXTRA » Sat Feb 24, 2018 9:53 pm

Yes - that's exactly what i do.

FB advice point to blocked return hose/pipe or failed thermostat.


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GTXTRA
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Re: What have I missed? Rad swap, new switch - fan now not kicking in

Post by GTXTRA » Sat Mar 10, 2018 3:10 pm

I've changed thermostat.

Flushed system with hose.

Refilled, bleeding, car goes to overheat, no warning light, gauge shoots up.

Fan still not kicking in.

Top hose hot

Rad cold.

Bottom hose cold.

At a loss.


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mr.brown
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Re: What have I missed? Rad swap, new switch - fan now not kicking in

Post by mr.brown » Sat Mar 10, 2018 3:54 pm

Reverse flush rad? Possible some old crud got caught in there.

Failing that, run without a thermostat to make sure there's flow.



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unknownmale
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Re: What have I missed? Rad swap, new switch - fan now not kicking in

Post by unknownmale » Sat Mar 10, 2018 4:03 pm

Maybe the rad is blocked?


- David

GTXTRA
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Re: What have I missed? Rad swap, new switch - fan now not kicking in

Post by GTXTRA » Sat Mar 10, 2018 4:36 pm

Brand new rad.


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GTXTRA
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Re: What have I missed? Rad swap, new switch - fan now not kicking in

Post by GTXTRA » Sat Mar 10, 2018 5:14 pm

Ok.
Now I’ve got
Top hose and bottom hose hot, rad hot.
No flow at 8mm outlet hose to bottle.

No fan kick in


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james butler
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Re: What have I missed? Rad swap, new switch - fan now not kicking in

Post by james butler » Sat Mar 10, 2018 7:29 pm

sounds like a manufacturing defect if coolant isnt coming out.
you could run a drill bit through the 8mm hose into the rad and see if its blocked.
or take the rad back and get it exchanged.
alternatively the pumps packed in?


I dont mind project cars but I HATE SANDING!!!

GTXTRA
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Re: What have I missed? Rad swap, new switch - fan now not kicking in

Post by GTXTRA » Fri Mar 30, 2018 5:47 pm

JAMES - I wish I'd read this answer properly when you posted it.

Turns out this rad DID have some sort of plug built in to the outlet for some bizarre reason.

Now sorted.

Phew.


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