Radiator fan not kicking in

[BriC]

OK, so I did a little search, and couldn't really find the info I require.

I have just replaced the rad on my new GTT due to the old one having a leak. I replaced it with a second hand one that was in my GTT that I'm currently rebuilding, and it was working fine before removal.

So I switched the rad, filled it with coolant, bled the system, and let it warm up to half way on the OE gauge. Normally the gauge goes further than this before the rad fan kicks in, right?

However, I'm a bit concerned because when you place your hand on the top right hand side of the radiator (near the fan switch), it's stone cold, and when you place it lower down, it's red hot, and all the pipes are getting very hot. Is this normal, or would it be a sign of a buggered rad? Or maybe an air lock?

The coolant pipes seem to be getting very hot too, and I'm a bit concerned that my OE gauge isn't very accurate, and I'm going to overheat the engine.

Also - do the wired on the fan switch go on in any order? There isn't a positive and a negative?

Cheers!

[tom t]

could be air in there still try bleeding it some more, i dont think it matters what way the wires go ont the switch either. might be wrong though.

[Misky]

I Had these problem when i got mine running.
That sounds like a defo air lock to me.

As for the wires it does not matter. :agree:

[Tiny Tim]

Air lock or fubared thermotw@t.

[BriC]

OK cool, so if it's an airlock in the rad, maybe an idea would be to connect a water hose to the top inlet, disconnecting the bottom pipe and letting the water run through?

[tom t]

not sure but i dont think that will work to gr8 m8

[TrixNFlix]

Best way of getting rid of the airlock is pressurizing the water system. Yep you've guessed it blow into header tank with the water pump bleed valve open. When blowing keep the pressure there untill all air has come out of the valve, when this happens keep the pressure up and close the valve. Works every time:agree:

[BriC]

I have essentially been doing that though. I have bled it by undoing the nipples (tee hee :D:scared:) and raising the header tank high, so that it forces all the air out of the system and through the bleed nipples (as the air escapes to the highest point).

[TrixNFlix]

Tried it with just lifting it up too and still left air in the system. Just leave the one nip open:) on the water pump and create the pressure slowly you can sort of feel when there is still some air in the system when you blow it:D then wash your mouth out

[TrixNFlix]

Did you give the radiator a good flush before you piped it up?

[BriC]

Nope

[TrixNFlix]

May well have bits of crap that have dried in radiator causing a bit of a block leaving air with no were to go? Just a thought

[BriC]

I'll get some pressure behind it! Blow any crap / airlocks out of it :)

[Tiny Tim]

Rad back out, hoses off the heater matric inlet + outlet and give them all a good blast through.

Reconnect it all, bleed it manually a couple of times, including running it upto temp... then use an Eezibleed kit to pressurise the system.

[TrixNFlix]

Oh my god just had visions of a coolant volcano 10metres high.:laugh:

[Tiny Tim]

That's pretty high.

[BriC]

That's pretty high.

It is. 10m high in fact.

[TrixNFlix]

Tis Even higher than 999cm:laugh:

[BriC]

Higher in fact than 9999mm.

[Tiny Tim]

What have I started :sad2:

[TrixNFlix]

I've heard it's higher than 9999999 microns :scratch:

[royz]

bric if you get stuck give us a shout and ill have a trip over

[Jay]

I'm 99% sure if you connect the wires up the wrong way then you're fan will be blowing the wrong way.
If you're not sure then when you get the fan working put a piece of paper in front of the bumper when the fans on and it should stay there on its own.
Jay

[djinuk]

I'm 99% sure if you connect the wires up the wrong way then you're fan will be blowing the wrong way.
If you're not sure then when you get the fan working put a piece of paper in front of the bumper when the fans on and it should stay there on its own.
Jay

I believe hes speaking about the rad switch wires, not the fan itself.

[Kenobi]

OK cool, so if it's an airlock in the rad, maybe an idea would be to connect a water hose to the top inlet, disconnecting the bottom pipe and letting the water run through?

No.

[BriC]

Sorted. Bled the coolant with the engine turned off by removing both water hose nipples, with the expansion tank lid off and the tank raised. Screwed the top rad hose nipple in first once bled, then the other nipple second, once I'd done that, with the expansion tank still raised higher than the rest of the coolant system, I pulled off the top rad hose which cleared the air lock in the rad and gave me a constant flow of water. Put the hose back on, started it up, and the radiator heated up properly and evenly, and my rad fan eventually kicked in. :agree:

[royz]

glad you got it sorted