Overheating

[Killer Rhubarb]

For a non mechanic... Speed 6 cerb. Random overheat. Doesn't appear to be losing water, buts it's like a kettle! Ideas to fix or what it could be?

Fancy a brew?

[gerradiuk]

Air lock ?

[Killer Rhubarb]

Easy fix?

[C3BER]

Are the fans coming on?
Is it truly hot and not a false boil?
Temp sensor working?

[Killer Rhubarb]

Think fans arnt coming on :/

[C3BER]

Not sure on the wires on a S6 but pull the plug on the temp sensor to see if they're working. They should now work constantly. Temp sensor is my honest bet and it seems it's temp sensor week for a few guys.

[C3BER]

gerradiuk said:

Air lock ?

I was getting air locks with my temp sensor woes sometime back.

[gerradiuk]

Just ordered a temp sensor from racing green so will be tackling it this week.
Rhub: when you pull the plug & both fans run the car never goes over 70-75c ,if the temp sensor has gone I expect when you fit the new one you will notice that the car runs better ie less rich!
If you do have to fit it wait until its stone cold , put cling film under the filler cap or zip tie a rubber glove to the filler neckthis will make it air tight , that way when you unscrew the temp sensor you will lose less water as there will be a vacuum so may not have to bleed it.;)

[Killer Rhubarb]

This is good info. Wheres the temp sensor? I know what one looks like, so there wont be any issue just taking this off until I fit a new one?

If it turns out to be an airlock, how do I go about this? Is it just a case of yanking off a hose and putting it back on?

Cheers all.

[Killer Rhubarb]

C3BER said:

Are the fans coming on?
Is it truly hot and not a false boil?
Temp sensor working?

Whats a false boil by the way?

[ukkid35]

I was unable to remove the temp sensor without removing the coolant pipe because I needed to press it out from inside. However, I wanted to ensure it was undamaged. I'll post a photo later.

[C3BER]

A false boil is when you get air into the system and you see it bubbling out of the expansion tank. Can be a sign of a cracked head etc. So rather than bubbling water you get when the fans fail you get bubbling water at a much lower temperature, i.e false boil.

Temp sensor on the 4.5 is under the F1 panel passenger side and near the radiator. It's a must to know the location incase you need to pull it to keep your fans on.

[Killer Rhubarb]

I'll jack it up tonight and massage me some pipe. Has to be an air pick before the switch, would cause fans not to come on right?

[gerradiuk]

KB the sensor is under the F1 cover near the passenger side about 10" back from the rad where the metal pipe's join. On mine its easier to see if you look at it from the drivers side across as its under pipe's etc. Its a 19Mm spanner as for the bleeding you may get away with it if you follow what i said earlier if not I think there are bleed points up under the airboxs possibly more ?
GL;)

[C3BER]

Not sure the bleed points on the S6? But open the rad and fill from the expansion tank until no air bubbles come out. Warm up the system and release any air from the top two water rails (v8). Top up if required and so on. If around the temp sensor it's cold then possible you now have a thermostat issue?

The fans should go to default on mode if you have a sensor fault but not if you have one like I had. The sensor said fine the sensor lied and the fans failed to turn on. Pulled the sensor and the fans worked.

[Killer Rhubarb]

Cheers all, flushed it all through bunged the bleed plug back on and problem gone. I was extra jumpy as its just had a lot of work done on it! Bloody marvellous outcome. Now celebrating with a packet of rich tea biccys