coolant hose/expansion tank mystery on me 1.9d conversion

Post by **oldiguana** » 04 Jun 2006, 22:22

eyup again ducks,ive finally got me 1983 holdsworth 1.9n/a diesbag running this weekend,for the first time(well chuffed)me next problem is figuring out where the long thin hose from the expansion bottle goes to,its about 1/2 inch thick and its got a jubilee clip on it so where does it go,ive read on some of the posts about a top up tank by the rear flap,should i have one of them,has anybody got any pics,or whats the best way to get around it,thanks to all who can help beforehand........cheers

Post by **trickydicky** » 05 Jun 2006, 07:05

Based on a 1.9 DG watercooled
If you are talking about the hose from the cap you are right it goes to the top up bottle. It is located quite centrally behind the number plate and joins the tank on the bottom right corner as you look at the vehicle from the rear. I am suprised you havn't noticed the bottle though

Post by **Mocki** » 05 Jun 2006, 07:09

you need a top up tank, or you have to take the engine lid off and fill the header everyday, i have one here if you need to purchase one, email me........

Post by **oldiguana** » 05 Jun 2006, 11:25

cheers to all with the help,ive just searched through a box full of stuff that came with the jigsaw(i mean van),it was at the bottom covered in crap and i never saw the little mountings around the rear flap,i would never had thought that there would be two of the bloody things!,total lifesavers all of you!!!!!!!!!!!!thanks again

Post by **angry vanagon** » 05 Jun 2006, 20:15

on my van i've never had a top up tank fitted in the last 2 years with my gti motor or my tdi engine the top up tank is only there for convience to save lifting the engine lid when loaded. you should never have to top up your water unless you have a leak the cooling system is a sealed system

Post by **Mocki** » 05 Jun 2006, 20:20

angry vanagon wrote:on my van i've never had a top up tank fitted in the last 2 years with my gti motor or my tdi engine the top up tank is only there for convience to save lifting the engine lid when loaded. you should never have to top up your water unless you have a leak the cooling system is a sealed system

Actually, if it is using the original header tank, it will "blow off" at temp and should suck back when cooling, so you DO need the top up bottle, or it cannot suck it back on cooling......

Post by **angry vanagon** » 05 Jun 2006, 21:51

i think you will find that the cap only "blows off" when cooling system presure reaches a preset pressure usualy around the 15psi mark nothing to due with the water temperature this is a safety feature to to stop the system exploding if the cooling system presure gets to high from over heating or engine faults. on cooling cycle with engine not running the system draws in air through a one way valve in the cap behind the top up tank spout this suction causes the expansion tank to draw coolant from the top up tank behind the number plate flap. so to sum up if you have no coolant problems eg leaks or air in system the van will never be low in expansion tank so will not need to draw from the top up tank and because the level will remain correct in expansion tank and everything works ok on the cooling system you will not over heat and the expansion tank will never blow off to get rid of excess pressure. the top up tank is only there so you dont have to move stuff out of the van to get to the expansion tank under the engine lid

Post by **oldiguana** » 05 Jun 2006, 21:54

thanks for all the info sound aza pound,i hope this thread is of use to other as it was to me

Post by **camper** » 06 Jun 2006, 12:45

Oh for a perfect non leaking engine.Seriously the expansion top up tank is a good safety device .I had a 1.6n T25 owned for ten years it had a recon engine in that time it had a water pump leak several hose connection leaks and head gasket problem.Driving around on my holidays it developed a water pump leak .But i was able to top my expansion tank up and not worry about pulling all the fitted seatbed storage and camping equipment off the engine cover.When i got back home i got the pump replaced.

Post by **Mocki** » 07 Jun 2006, 17:39

angry vanagon wrote:i think you will find that the cap only "blows off" when cooling system presure reaches a preset pressure usualy around the 15psi mark nothing to due with the water temperature this is a safety feature to to stop the system exploding if the cooling system presure gets to high from over heating or engine faults. on cooling cycle with engine not running the system draws in air through a one way valve in the cap behind the top up tank spout this suction causes the expansion tank to draw coolant from the top up tank behind the number plate flap. so to sum up if you have no coolant problems eg leaks or air in system the van will never be low in expansion tank so will not need to draw from the top up tank and because the level will remain correct in expansion tank and everything works ok on the cooling system you will not over heat and the expansion tank will never blow off to get rid of excess pressure. the top up tank is only there so you dont have to move stuff out of the van to get to the expansion tank under the engine lid

i think you'll find NOT, WBX's will run dry without the header being connected to the top up tank, i know i've done it..... perhaps they blow off at lower pressure?

Post by **R0B** » 07 Jun 2006, 17:48

hhmm if you dont need it.why did vw go to the bother of putting it there.

Post by **angry vanagon** » 07 Jun 2006, 21:28

so the van driver with a pallet on top off engine lid can top up leaking cooling system with water without having a forktruck

Club 80-90 Forums

coolant hose/expansion tank mystery on me 1.9d conversion

coolant hose/expansion tank mystery on me 1.9d conversion

problem solved lads thanks very very much

top up tank

Re: top up tank

expansion tank

sorted ducks no probs

Re: expansion tank