Movement thermostat pipe work

[SD1too]

Originally Posted by BruceH

Unless the single bolt is tightened so much ... there is bound to be some play ...

That's not true I'm afraid Bruce. The bolt should be tightened only to MG Rover's specified torque. Did you do that?

I also refer you to my post number 5 which describes the correct setting of the clips on the straight pipe. That will prevent movement since the whole assembly will become rigid. If you haven't done that, from my experience it's only a matter of time before your 'O' rings start leaking again.

Simon

[BruceH]

Originally Posted by SD1too

That's not true I'm afraid Bruce. The bolt should be tightened only to MG Rover's specified torque. Did you do that?

I also refer you to my post number 5 which describes the correct setting of the clips on the straight pipe. That will prevent movement since the whole assembly will become rigid. If you haven't done that, from my experience it's only a matter of time before your 'O' rings start leaking again.

Simon

Thanks for the correction Simon, all noted.
I tightened mine pretty darn tight without torquing it. The clips were on the old tube in original positions and tube reused with new O rings. Old system did not leak, replacement required due to slow warm up, so suspected stat stuck open. All works well now.
I see how you think it would be rigid with all located properly, so would I think that, but it does move. I could rotate the housing a little around the bolt with the vertical stub rocking in crankcase and the housing stub to straight pipe moving in and out slightly.
I think if the clips were spaced too far apart then the housing would be off line slightly and pipe joints would be skewed. The stiffness of the bolt/brackets/webs appears not so great to prevent flexing and movement in several directions. Also it would only take a bit of grit on the crankcase seating of the housing lug by the bolt hole to allow quite a bit of movement and possibly cause a crack on tightening, but I doubt this is the case. I think (hope) the greased O rings will continue to seal and that the joints hardly move in use. As usual, time will tell!

[SD1too]

Hi Bruce,

Some thoughts on the points you've raised:

Originally Posted by BruceH

I tightened mine pretty darn tight without torquing it.

I'm curious to know why didn't you use a torque wrench?

The clips were on the old tube in original positions ...

The original positions aren't necessarily the same as the correct positions. They weren't on my engine.

I could rotate the housing a little around the bolt with the vertical stub rocking in crankcase ...

I bought the upgraded thermostat housing with the three stabilising legs from E Car Parts Ltd. in Sandy, Beds. Perhaps you've got an inferior moulding?

... and the housing stub to straight pipe moving in and out slightly.

The straight pipe won't move if you set the clips as I've described; it cannot!

Simon

[minimutly]

Aside from any issues with the horizontal pipe from the stat to the block, the v6 has an issue with the stat to radiator pipes moving around. This, I believe, stresses the thermostat housing, causing the thing to move around, potentially cracking it and wearing the oring below and on the horizontal pipe.
My fix was to zip tie both pipes together, and to something nearby (sorry, it was years ago, I forget what it was now).
Those two pipes hold a fair weight of water, and there's b.all stopping side to side movement as std.