Heater bypass valve mod

[antgel]

Just reading about this mod in the sub-forum, as my car has had it.

Can someone explain what the heater bypass valve actually did when it was in the car, and why it is not needed?

[Uruk Hai]

What it did was allow the water to flow around the system without all if it flowing through the matrix thus lowering the water pressure in the matrix. They were fitted as part of a VW recall because apparently some of the early cars had the heater matrix split on them due to the pressure of the water system but over time these bypass valves seem to affect how hot the heater is so many people remove them and place normal 22 mm copper tube in the place where the two parts of the valve were fitted. Also some people fit a matrix from a MK3 as they are stronger and far less likely to fail due to pressure. My car has had the bypass valve removed and the two pieces of pipe fitted in its place, I haven't had any trouble after having the car for six months and the heater is very hot 

Have a look at this and you'll understand 

http://www.golfgtiforum.co.uk/index.php?topic=31666.0

[antgel]

What it did was allow the water to flow around the system without all if it flowing through the matrix thus lowering the water pressure in the matrix. They were fitted as part of a VW recall because apparently some of the early cars had the heater matrix split on them due to the pressure of the water system but over time these bypass valves seem to affect how hot the heater is so many people remove them and place normal 22 mm copper tube in the place where the two parts of the valve were fitted. Also some people fit a matrix from a MK3 as they are stronger and far less likely to fail due to pressure. My car has had the bypass valve removed and the two pieces of pipe fitted in its place, I haven't had any trouble after having the car for six months and the heater is very hot 

Have a look at this and you'll understand 

http://www.golfgtiforum.co.uk/index.php?topic=31666.0

Actually, I had seen that thread.  But it didn't explain what the valve did.  Your explanation above hit the mark though, thanks. 

[[han]]

the recall finished 6 years ago, but if u still want it doing VW can order the parts and do the job for a total of £400... im looking for copper pipe and will ask my brother nicely! 

[Lewy]

Sod the ugly copper pipe, just buy the new hose from VW, it costs about £17 and takes about 5 mins to fit. When I get back home later I'll dig the part number out for you.

[VeeDubGTI16v]

it just bypassed the steam when it got too hot or too pressurised away from the matrix.  in my opinion if you want to do the copper pipe thing you must put the mk3 matrix in there as it wont blow up apparently the valve is obsolete now, but i managed to get one about half a year ago so its worth viisiting the dealer

[stan_deezy]

Get the hoses from GSF at £8.50 each. New matrix isn't very expensive either and set aside a few hours at the weekend to change it using the rubjonny guide on the subforum. Hey presto! One good heater, loads of luverly heat for the winter (or summer the way it is today!) and no pesky bypass valve to worry about again.

[Dub_Dude_16v]

The by-pass valve is back in production now due to popular demand 

[[han]]

was i talkin to myself when i said vw cud still get parts? the whole recall can be done for £400?

parts can obv still be bought?