Thread: Timing cover breather?

The purpose of the breather is that if you're in a bog hole or under water (with the wading plug in) the metal cover contracts slightly with a change of heat and will suck water in through the mating surface of the timing cover. This will cause water to enter your timing belt area. Having a breather means that the change to a relative negative pressure in the timing cover when it's cooled, will not compromise the sealed mating surface, as air will enter through the port of least resitance, which is the breather, and that air will be clean.

It's the same principle as a diff breather. Some people put similar breathers on their winches and actually run a low psi positive air pressure into the housing so that when submerged, there is no chance of water / mud ingress.

Originally Posted by johntins

.... actually I don't. why is the hole there in the first place,

.... But why a breather? I'ts not as if the timing belt cover is perfectly sealed, is it? What pressure is in there, or vacuum for that matter, that would need a dedicated breather, and if there is, why didn't LR fit one. The things are 20 years old.

Originally Posted by AK83

.....

I've only forgotten to release the collected oil on one occasion in the two or so months I've had my tap setup going.
Oil built up in the (clear) hose, but what happens is, if it does build up, there's enough pressure in the timing cover area to blow excess oil out of the end of the hose, at the fresh air end.
If you have the end of the breather hose oriented internally to the engine bay, it seems to be a great way to lubricate your steering shaft ....

Like I said, it blow collected oil(in the breather hose out with pressure.

If the screw plug is fitted without a breather pipe of any type, I guess it'll continually build up pressure, until that pressure is released somehow. From memory there appeared to be three internal oil seals(IP, cam and crank oil seals) .. and the one external seal(front cover seal).
So one of those four, or the gasket would have to release the pressure build up.

I currently have my breather hose oriented up to the shock tower, then looped back down which points directly at the steering shaft.
When I forgot to release the oil out of the tap the other week, there's an oil spray all over the steering shaft and chassis!

I remembered to open the tap this morning(just after my reply to this thread) .. barely 50mls or so eventually came out after a couple of hours sitting.

Then I did my glow plugs.