JST Posted April 2, 2006 Share Posted April 2, 2006 i am running a 200tdi. i wish to git a 300tdi header tank. the 200 has a small pipe from the top LHS (viewed from front) of the radiator that goes into the top of the current metal expansion tank. the 300tdi has this same small pipe going to a Y piece that then goes to the expansion tank and the thermostate housing. can i plumb the small pipe from the top LHS of the radiator straight into the bottom of the 300tdi expansion tank? what does this small pipe do, is it to aid the bleeding of the system (let air out) or is it there to allows some of the fluid to cycle through the expansion tank. Will the pipe going into the bottom of the expansion tank, rather than the top (above water level) make any difference? many thanks for your help Quote Link to comment Share on other sites More sharing options...
western Posted April 2, 2006 Share Posted April 2, 2006 Just fit the later plastic retangular header tank & plumb it as per the existing one, I've done it on my 200Tdi, will do a few pics & add them shortly for you. back in a few minutes with pics Quote Link to comment Share on other sites More sharing options...
JST Posted April 2, 2006 Author Share Posted April 2, 2006 so, small pipe from top of rad to bottom of expansion tank then? Quote Link to comment Share on other sites More sharing options...
western Posted April 2, 2006 Share Posted April 2, 2006 so, small pipe from top of rad to bottom of expansion tank then? Yep, just like mine has in this picture as promised seems to work OK, not had any overheating or overspill problems, genuine factory built 200's had this tank from new. Quote Link to comment Share on other sites More sharing options...
JST Posted April 2, 2006 Author Share Posted April 2, 2006 Ralph, many thanks. i have plumbed mine the same, took it for a spin and whilst thermostate opened and rad warmed up the expansion tank didnt get hot/warm, so just wondered if i had it right, i guess a longer run will tell. i did get it upto working temp though and ran it there for 10mins so would have thought things may have warmed through. thank you for the help. Quote Link to comment Share on other sites More sharing options...
western Posted April 2, 2006 Share Posted April 2, 2006 happy to help Quote Link to comment Share on other sites More sharing options...
simonb Posted April 2, 2006 Share Posted April 2, 2006 The pipe is a air bleed pipe. With it connected as per pic, as system cools it will draw in more fluid. If the connection was above the fluid level, as the engine cooled it would draw in air. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted April 2, 2006 Share Posted April 2, 2006 Would that matter? Mine's above the water level... Quote Link to comment Share on other sites More sharing options...
simonb Posted April 2, 2006 Share Posted April 2, 2006 Suppose it will still will probably draw in coolant from the "normal" route, but if below the water level means then it definetly can't draw in air..... Quote Link to comment Share on other sites More sharing options...
Les Henson Posted April 17, 2007 Share Posted April 17, 2007 The pipe off the top of the rad is for letting air out of the cooling system, and the one from the thermostat housing is a bypass hose. I don't think it matters if you join them as long as they eventually go to the header tank. Les Quote Link to comment Share on other sites More sharing options...
Guest WALFY Posted April 17, 2007 Share Posted April 17, 2007 Yep, just like mine has in this picture as promised seems to work OK, not had any overheating or overspill problems, genuine factory built 200's had this tank from new. That is the same setup that I have in my 90. I've got a Disco TDI, no problems yet. Quote Link to comment Share on other sites More sharing options...
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