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[amba]

Just so I am clear in my own mind regarding the plumbing at the rear of the V6.

Bottom helter skelter pipe from HBV connects to top of metal coolant pipe..other end to quick fit on bulk head ..bottom pipe
Top hbv pipe goes straight to top quick fit connection on bulk head to heater matrix.

Single pipe end of hbv goes to larger of the 2 stubs on the coolant bridge
Thin pipe which runs from throttle body on n/s bank connects to thin stub on coolant bridge

Why does the coolant bridge require dowty washers to seal it as is it  not just a casting for coolant to flow through ?
 

[feeutfo]

(Snip...)
Why does the coolant bridge require dowty washers to seal it as is it  not just a casting for coolant to flow through ?
 

Why's ask A? Not sure what you mean?

[amba]

Just wanted to understand I have got the plumbing order correct in my own mind before I start pulling things apart...fore-warned and all that.

On the coolant bridge gain just wanted some clear reasoning as looking at pictures it seems to just be a casting which bolts down onto the oil cooler...unsure why the washers would leak unless I am missing some technical information

I suppose it will become clear when I start pulling it all apart to find..I hope ...the cause of the leak .

[razzo]

the coolant bridge connects to both heads & not the oil cooler, the bolts are hollow so coolant flows from 1 head through bolts, through bridge, through other bolt & into the other head, the dowty washers are metal with a rubber coating so when its all bolted down its water tight. The washers are usually damaged during removal so need replacing on assembly

[amba]

Perfect explanation .

Didnt know bolts were hollow so now I understand how and why it could be possible for a leak to appear at that area.Many thanks for clearing that up in my mind .

Could seals perish with age ?? although I understand they could deteriorate with poor coolant levels .

[Marks DTM Calib]

The dowty washers are key, I have seen ordinary rubber washers used which gave intermittent temp gauge readings!

On the plumbing, I cant recall, its one of those things I sort of do on auto pilot these days

[amba]

Sure it will all become clear when I pull it apart this morning

Lets hope the leak is from a split pipe or seal on the bridge

[Marks DTM Calib]

Depends how bad the leak is, I have seen the helter skelter pipe split (big leak)

Thinking about it logicaly, the helter skelter pipe is the hot feed to the bypass valve so would come off the coolant bridge.

The cold/cooler return goes to the metal transfer pipe so this will be the one that connects to the bypass vlave and bulk head.

[Matchless]

Depends how bad the leak is, I have seen the helter skelter pipe split (big leak)
Thinking about it logicaly, the helter skelter pipe is the hot feed to the bypass valve so would come off the coolant bridge.

The cold/cooler return goes to the metal transfer pipe so this will be the one that connects to the bypass vlave and bulk head.

Enough water spraying onto a hot exhaust to fill the southbound A5 with steam as I remember

[Matchless]

Use the tip of a spare water filler cap, hole drilled in centre and a tyre valve stuck in with a bit of silicone to seal. You can then use a foot pump to put 7 - 10 psi on the cooling system whilst you look for the leak (s).

[albitz]

And just take a pic of it after removing the plenum so if you cant remember where something goes you can refer to the pic.

[amba]

Thanks for words of inspiration,guys.

All pulled apart and found small split in pipe that runs from coolant bridge to single feed side of hbv.Difficult to see as split was hiden by the spring clip but after removing can clearly see where split is and just rang local dealers and they can move 1 from another branch to closer for me to arrive about 4.30 today.So even though car will be off road today looks like with a morning work tomorrow all will be water tight again. .

Also removed and replaced the coolant bridge washers whilst there as had set for another job but when refitting them the book of words says torque to 30nm which I have done.They felt a darn sight tighter than that when I removed the hollow bolts.Can somebody just confirm bridge coolant hollow bolts at 30nm is correct

For reference the pipe in question is part # 90466222 so expect that will not be cheap but needs must.

[the alarming man]

(Snip...)
Why does the coolant bridge require dowty washers to seal it as is it  not just a casting for coolant to flow through ?
 

Why's ask A? Not sure what you mean?

Whole idea of the forum is it not ?

[Debs.]

For reference the pipe in question is part # 90466222 so expect that will not be cheap but needs must.

Bought one myself, last week: £8.18 inc.VAT (with a 'blagged' T.C discount; always pays to ask!)

[amba]

Picked mine up last night from local VX dealers ,who I must say went out of their way to help me

£6=82 +VAT on t/c and about 3 hours of grief  this morning getting it all back together but the car is now water tight and had  a good clean of throttle/breathers/plenum etc whilst apart so fingers crossed