How to fit a radiator switch

[sternal]

Took van for a spin today then left it to idle outside for 20mns and got these readings...



still no fan



still no fan


still no fan

[]



So fan is not cutting in and I guess with those readings it should be, van is not over heating but its got to be a good idea to have it working.

Please can I have clear instructions as how to swop over the switch ?

Engine hot or cold etc bleeding rad etc


Many thanks

[Aidan]

does the fan work ?
remove plug from switch on radiator and bridge appropriate contacts (one end is live, the other two are the two stages of motor for fan) with some decent wire to get fan to run, if fan works then replace switch in radiator, if fan doesn't work then test for live supply at plug, if present continuity check to motor and if circuit good then motor failed

[sternal]

Yes fan works long thread from last week!

[Ian Hulley]

Park with nose raised (I didn't but I guess it makes sense really ?), remove bottom rad grill, remove plug, have replacement switch to hand (with gasket fitted), unscrew old switch, quickly fit new switch, refit plug and grill.

You'll only lose a tiny bit of coolant so shouldn't have to bleed the system (or I didn't).

Ian

[Mocki]

What Ian said, BUT engine COLD , you will loose some coolant, and you don't want hot coolant on your hands , I read somewhere recently it's at 92-98° c or so !

Seriously, do it with the engine stone cold, that way the thermostat isn't open , so the engine is unaffected, as the rad is on a closed circuit..... And it's not under pressure, and you won't scold your pinkies....

[pionte]

is the temp gun accurate ? have you tested with a boiling kettle ? how hot is the rad to the touch ?

[sternal]

Not scorching boiling you couldn't leave your hand on it seems acurate did point at the kettle and it read 98c after boiling

Looking at fan cut in temps on wiki it could be that it's still not hot enough to cut in...

[DuaneEddy]

Guy's
I've used these meters in the pictures and you get different readings whether it is matt black or shiny

Question
Is the switch 3 pin or 2 pin?

Resolution
Order new - fit when engine cold - test
As Ian (and boy's) have said if engine cold - no burny - you should not need to bleed if you are quick replacing switch - water loss is minimal

[Mocki]

As Ian (and boy's) have said

Hmm...

[Ian Hulley]

Good point on the 'COLD' radiator ... well-spotted Pike

[sternal]

thanks for help will swop over on a nice non rainy day !

1. If it was to get air in the system how could I tell ?

2. To get air out of the system top left hand-side(looking at rad) with a nut (13mm) ?Bleed screw ?

3.If its done from cold why would this eradicate getting air in system ?

4.The coolant thats lost when replacing the switch should the same amount be put back into the first tank (by number plate )?

Trying to make this as foolproof as I can !

[Ralf85]

[sternal]

by Ralf85 » thank you for your useful contribution...Ralf any chance you can answer the questions...or even better can you fit it for me(youre only round the North Circ wont take you long to drive over !)...?

[Mocki]

If the system is hot, as I said earlier, means the thermostat will be open, meaning the whole water system is connected and flowing, so apart from not burning yourself, by doing it stone cold the thermostat will isolate the rad circuit, meaning the only place the air can go is the rad circuit, and also means that the will be a vacuum in the system, meaning less coolant will come out of the switch oriface because no air can get in other than through the hole the coolant is coming out of.

You won't need to top up any unless you take ages and let lots out.
If it's one out one in you will loose less than a cup full, the top up tank ( behind the number plate flap ) will compensate that small amount and you shouldn't need to fill the header tank ( in the engine bay only accessible with the hatch off)

Don't undo the bleed screw on the rad!

It really isn't as complicated as you are anticipating ?

[Cruz]

Hurrah for Ian's Boy on the HSE tip