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.

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Originally Posted by WazDef

I know this is an old thread but the fear is real. Here is what happened to my 300tdi when i went into a mud hole with no wading plug in the timing case.
I have a video where you can hear the motor fail about 4 seconds after entering. Had to get towed out and to a road where a tilt tray took me home.
My advice is Either Never forget to put your plug in or leave it in and add a breather. I chose the latter.

Attachment 124851

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I appreciate why the plug is needed. Well, actually I don't. why is the hole there in the first place, unless it's to see if the front seal is leaking...[bigsad]? I know what can happen if the plug is left out. 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.

I can confirm the timing case is sealed with the plug in. I blow into the breather pipe and it holds pressure.
Not sure how other engines are designed. Hilux has a plastic cover no plug and no breather that visible.

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Originally Posted by WazDef

I can confirm the timing case is sealed with the plug in. I blow into the breather pipe and it holds pressure.
Not sure how other engines are designed. Hilux has a plastic cover no plug and no breather that visible.

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Ok. I never actually checked, given that the fuel pump timing is accessed through the hole behind the pulley. So, why not just drill a hole at the top?

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Originally Posted by johntins

Ok. I never actually checked, given that the fuel pump timing is accessed through the hole behind the pulley. So, why not just drill a hole at the top?

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That's what i did. Could not use the eBay version because I have an ac compressor for on board air.Attachment 124977
Attachment 124978
Attachment 124979
Now with a hose attached.

Note the shape of the housing. Looks like it was designed for a breather.

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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.

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Originally Posted by AK83

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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 ....

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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.