Radiator switch

[T25vanman]

Hi all. Is there a way to check that the radiator switch operates correctly without running the engine please?

[CovKid]

Well no, not without removing it and if you do that you'll lose the water out the rad. Just change it if you're not sure about it.

[T25vanman]

Should putting it into a cup of hot water plugged in make the fan kick in?
I tried this earlier with the new one, although it was hard to keep in cup due to shortness of wires.
It also didn't work so unsure of new one being duff or just an inadequate way of testing.

??

[pirate-pete]

Should putting it into a cup of hot water plugged in make the fan kick in?

Water would have to be close to boiling depending on switch.

Bentley manual shows stage 1 cuts in at between 93-98 deg and cuts out at 88 to 93 deg. Stage 2 is 99 deg to 105 deg cut in and 91 to 97 off. These figs for up to 1986.

1986 on is 89 to 94 on and 81 deg off for stage 1 and second stage at 95 to 100 on and 87 deg off.

With after market switches the temps will vary but the above give you an idea on how hot your cup of water will need to be. If you can try and stick it in a pan of boiling water with temp leads attached connected to a multimeter. See if the stage 1 contacts close when the water gets to boiling. You might not get the second stage to kick in though as you will need more than just water to get over 100 deg in the pan.

[T25vanman]

This explains why it didn't work then.
I've tried braiding the connections to the fan and it kicks in on both.
I'm guessing......hoping, it's the sensor.

Although I have also found a pin prick hole below the pressure cap on the header tank which spirits water when pressure and heat builds.

I assume that this could have an adverse effect on the flow and operation of the cooling system but not sure why. Any takers??

[AdrianC]

Although I have also found a pin prick hole below the pressure cap on the header tank which spirits water when pressure and heat builds.

I assume that this could have an adverse effect on the flow and operation of the cooling system but not sure why. Any takers??

Because the cooling system can't get up to full pressure, so can't get up to full temperature without boiling.

[T25vanman]

I think I've sorted the van
Changed the header tank, level sensor and also the fan switch. All pressurised, no leaks and fan kicks in. Temp gauge reads as it should do.
Oh I do feel proud of myself.
And after only 3 hrs sleep after nights too.
Now for a shower and off to work.

Thanks everyone for your help with this.

[pirate-pete]

I think I've sorted the van
Changed the header tank, level sensor and also the fan switch. All pressurised, no leaks and fan kicks in. Temp gauge reads as it should do.

Well done. Not sure how well you can test the second stage of the fan without thrashing the van. Mine never runs hot so have never had it kick in on mine. Apart from when the switch failed in closed position and you certainly know from the sound it makes that is running on high speed. My neighbour thought I had left the engine running!