12v Coils

[LarryH57]

IMBS - but after finding some spare coils in the loft I gave them a shake and I could hear liquid inside; is this normal and does it mean they are unusable? Understandably when I have changed a coil before I have taken the new one out of its bag and just fitted it. Shaking it is the last thing I would have done that's why I have never noticed before!

[fv1609]

That's the oil that is there to transfer heat mainly from the primary winding, which is actually wound over the secondary, to the case. It also confers insulating properties.

 

If you can hear liquid it suggests some air has got in as the result of oil leakage. Many coils are filled via a hole in the HT terminal. The central screw has a bunged washer this maybe be loose. For that reason there is an argument that suggests a coil should be mounted with the terminals uppermost.

 

Insufficient oil causes overheating so that the coil fails. You then search for the fault, find nothing and then it runs again until it overheats again!

[LarryH57]

I wonder why Land Rover decided to mount the coil horizontally over the engine then!

[fv1609]

Well yes there are large numbers of vehicles of various kinds that have horizontal coils. The manufacturers clearly have confidence in the integrity of the seal.

[woa2]

Insufficient oil causes overheating so that the coil fails. You then search for the fault, find nothing and then it runs again until it overheats again!

 

I know, I know!!! Had it happen twice now on the same vehicle but about 10 years apart.

[LarryH57]

That's why my 'get me home spares box' now has a selection of coils and condensers to choose from!