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Author Topic: confused about bypass valves  (Read 890 times)

Offline GTIrl

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confused about bypass valves
« on: 08 December 2006, 12:50 »
ive been reading a few threads about them as im having problems with my heater only putting out luke warm air.. and now im confused.
 some people said cut out the bypass valve altogether, and others said bypass valve stops the matrix getting too much pressure and bursting, so they are needed.
so... which is it? it would certainly be alot easier just to cut them out, but i dont want to knacker my matrix... :huh:
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Offline NewStu

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Re: confused about bypass valves
« Reply #1 on: 08 December 2006, 12:57 »
Well back in the day there was a law suit as somebody claimes they got scalded by a bursting heater matrix. So VW re-called the cars and fitted bypass valves which do as they say on the tin. Bypass the water as soon as the pressure builds up. However the matrix's in reality are fine and if they do go dont burst, simply dribble and leak in which case they were old and weak anyway. The valves at the age they are now are failing at a rapid pace leaving people cold. So the best solution is to remove them and bridge the gap they leave with a bit of copper pipe. If your matrix does start to leak then its time to upgrade it to a mk3 item.
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Offline GTIrl

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Re: confused about bypass valves
« Reply #2 on: 08 December 2006, 14:18 »
ok, thanks for clearing that up.

hot water is getting through past the bypass valves so it cant be them that is at fault, can it? for some reason it doesnt translate to hot air...

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Offline 16v

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Re: confused about bypass valves
« Reply #3 on: 08 December 2006, 15:05 »
Just to add too this thread (sorry)....

Is the Mk3 matrix into a mk2 a straight swap? as mine has the same problem......biz heaters.
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Offline Uku

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Re: confused about bypass valves
« Reply #4 on: 08 December 2006, 15:13 »
yep it can still be them as they jam slightly open so a bit gets through but not alot , mine did it and took out the headgasket whilst it was at it , i think there a bad rushed design and should remove asap.
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Offline NewStu

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Re: confused about bypass valves
« Reply #5 on: 08 December 2006, 15:21 »
yeah it would have been better if vw had changed the matrixes but that would have cost them more. As far as i know the mk3 matrix is a straight swap.
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Offline rubjonny

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Re: confused about bypass valves
« Reply #6 on: 11 December 2006, 12:01 »
MK3 matrix is a straight swap, in theory thats all you should be able to buy for the MK2 anyway, the MK2 matrix was replaced with the MK3 matrix which is strong ehough to take the pressure :)
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Hello my name is John and I'm a dub addict.

Offline GTIrl

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Re: confused about bypass valves
« Reply #7 on: 12 December 2006, 16:02 »
its so warm and toasty in my car now, i had to turn the heating down!
fingers crossed the matrix isnt 15 years old... probably is..
 :rolleyes:
anyway, thanks for the advice. great as always. there is no way i could have owned this car as long as i have without you lot :smiley:
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