Cooling fan woes

[Topper_Harley]

Running out of ideas here.
Otter switch wiring has melted after coming into contact with the manifold.
I've replaced the wiring and run everything up to temp but no fans.
Connected the otter switch terminals, hey presto, fans.
Replaced the otter switch, bled the coolant, still no joy.
Resistance across the otter switch does drop as it heats up and I have many small burns from adjusting and testing.
The fans still fire up when I bridge the terminals or connect the wires.
What have I missed?

[portzi]

It definitely sounds like you have an airlock somewhere, keep bleeding the system, radiator, swirl pop, expansion tank, heater pipe rail next to alternator, just undo the jubilee clip until coolant drips out then re tighten, and bleed pipe on top front of the engine passenger side next to the disused rover temperature sender. Engine running with heater control turn to hot.

[Topper_Harley]

Mark, why aren't you still around the corner?You could fix this for me!
Selfish

[Bluebottle]

to rule out a faulty Otter switch test it in a pan of heating water to see when/if it switches. If it switches correctly then as above most likely an air lock.

[portzi]

Topper_Harley said:

Mark, why aren't you still around the corner?You could fix this for me!
Selfish

Hi topper,

Wish i could help, have alook at my profile address, its about a 5 hour journey Via a Airbus

[QBee]

Shirley you only lost a cup full of coolant changing the otter switch. Whip it out and bang the new one in. So there shouldn't even be an Airbus in the system.

I suspect you simply have a faulty replacement otter switch, as you have proved the new wiring is fine.

[Topper_Harley]

Don't call me Shirley.

Air lock would make sense as I haven't proven that the original otter was broken and the problem has been there since a very expensive 12k service from a TVR specialist which involved tidying up wires in the engine bay.

Only ever been to Cyprus on a Tri-Slum, Airbus is far too upmarket!

[portzi]

Topper_Harley said:

Don't call me Shirley.

Air lock would make sense as I haven't proven that the original otter was broken and the problem has been there since a very expensive 12k service from a TVR specialist which involved tidying up wires in the engine bay.

Only ever been to Cyprus on a Tri-Slum, Airbus is far too upmarket!

You're ex life in a blue suit, l never new !!. It's the new voyager for brize the queens very best with civvy stewardesses happy days.

[ianwayne]

Is there not a relay involved in the circuit?

The fans don't run unless the ignition is on, so unlike other cars, the fans aren't direct connected to the battery.

[Loubaruch]

Yes indeed,

Rough circuit diagram here:

http://www.bertram-hill.com/cooling-fans-schematic...

Well for a Griffith but should be the same.

[Topper_Harley]

Portzi, never worn a blue suit! Was a trooping flight many moons ago as a stinking student.

Appreciate the wiring diagrams and have proven that the relays are OK.

Rammed a funnel into the swirl pot, bled the rad, ran it up to an indicated 100 and still no fans. I burped a bit of air out of the big hose from the swirl pot.
I've released the jubilee clip on the heater rail manifold but was too scared to jiggle it and have a hot coolant wash so nothing came out.
Same story on the inlet manifold bleed.
Might try again with a cold engine and some cement tablets to harden the fluck up.

[Bluebottle]

Have you rested the otter switches in a pan yet?

[Topper_Harley]

Bluebottle, no. Fed up burning myself but it is on the list of desperation :-)

[Bluebottle]

Topper_Harley said:

Bluebottle, no. Fed up burning myself but it is on the list of desperation :-)

small saucepan of water and crocodile clips on the ends of your test leads...no burning involved

[portzi]

Bluebottle said:

Topper_Harley said:

Bluebottle, no. Fed up burning myself but it is on the list of desperation :-)

small saucepan of water and crocodile clips on the ends of your test leads...no burning involved

It would be unlucky to have both your old and new otter switches fail, at least with this test you can rule out these.

When up to temp is the heater blowing out hot air?

[portzi]

Portzi, never worn a blue suit! Was a trooping flight many moons ago as a stinking student

Your correct about students Topper,they all have B.O .

[Topper_Harley]

Yes, blowing hot air.
I understand that to mean the coolant is circulating.
Almost bought another switch but will bleed tonight and put the original switch is in a saucepan.
The burn blister on my forearm has just popped.

[Topper_Harley]

Time for an admission.
I bought a replacement otter switch from Intermotor via ebay and this didn't solve the problem.
I boiled both switches and proved to myself that both work.
Basically, after much messing about and a lot of coolant on the driveway, it must have been an airlock.
Now running with the original otter switch (Intermotor one just didn't seem to work in situ).
As many have said before, I'm checking the swirl pot after every drive and topping up as necessary. Fans are kicking in and switching off automatically.
I'm expecting it to improve and kick in at lower temps as I progressively remove all the air.
Thanks for all the suggestions, just concluding the thread as I found it mildly frustrating to see some unfinished ones during my research!

[portzi]

Topper_Harley said:

Time for an admission.
I bought a replacement otter switch from Intermotor via ebay and this didn't solve the problem.
I boiled both switches and proved to myself that both work.
Basically, after much messing about and a lot of coolant on the driveway, it must have been an airlock.
Now running with the original otter switch (Intermotor one just didn't seem to work in situ).
As many have said before, I'm checking the swirl pot after every drive and topping up as necessary. Fans are kicking in and switching off automatically.
I'm expecting it to improve and kick in at lower temps as I progressively remove all the air.
Thanks for all the suggestions, just concluding the thread as I found it mildly frustrating to see some unfinished ones during my research!

Thanks for the update Colin, glad your finding your way around your car and getting used to its behaviour