Metal gasket

[Tetsu0san]

I decided to fix the leaking 'P' gasket behind the water pump housing on my 300Tdi Disco today, and I was amazed to find a rusty metal gasket in there.

It had been leaking for a while by the look of it, as there was loads of RTV sealer all over the place, seemingly not from the original installation of the gasket. It was smeared all over the joint and looked a right mess.

My question is has anyone else come across a metal 'P' gasket before? It certainly suprised me to see it in there. Head gaskets are one thing, but this was a little odd.

[Disco1tdi]

I'm pretty sure the last one I put in, was.

That said, I did thoroughly coat the faces and gasket in sealant, before putting it all back together.

[Les Henson]

The original ones were gasket paper if I remember correctly. Coated shim steel gaskets were introduced in an attempt to stop the leak problem. The problem isn't the gasket at all but distortion of the alloy cover.

Les.

[JimAttrill]

You must never use the paper gasket as a section can blow out closely followed by all the coolant. The replacement metal and plastic version (part no starts PET...) Should be used. At worst it will leak a bit but it cannot blow out. Most people use a bit of RTV on the gasket, and if you used grey RTV you can see the difference between the RTV and the gasket plastic coating. My guess is that someone has used black RTV on your engine, and when you take it apart it seems to be a metal gasket with RTV.

I note the Bearmach engine gasket sets come with a paper gasket. Throw it away, the metal/plastic one isn't expensive.

The reason for the problem with leaks is that the joint faces are cast iron and aluminium which is asking for trouble as they expand at different rates. This is why head gaskets tend to be thick, metallic and rather expensive as they are designed to cope with this.