Nothing but cold air....FIXED!!

[skinnyman9000 0]

This morning my heaters threw out freezing cold air, even when the oil hit 100c the air was luke warm at best. Can't really live with this as we've been forecast sub zero temps for the next fortnight.

 

What's the crack then?

[Slimg60 0]

3 way valve might be blocked.

It's in the engine bay located near the bulk head.

[skinnyman9000 0]

I'll have a gander.

 

Don't suppose anyone has an engine bay pic they can use to point the valve out? I've gotta look over my lunch break so wanna find it sharpish

 

cheers

[Slimg60 0]

Not got a picture, but it's just to the left of the expansion bottle. A metal 3 way piece with 3 rubber hoses attatched to it.

[veedub16v 0]

do corrado's have the bypass valve for the matrix like mk2 golfs? If so its pretty much guaranteed to be that sticking!

[davidwort 0]

do corrado's have the bypass valve for the matrix like mk2 golfs? If so its pretty much guaranteed to be that sticking!

 

that's what he means, two by-pass valves ones metal the other black plastic, linked with a small bore hose, and are situated just before the bulkhead where the heater hoses enter/exit the dash.

 

take them off, soak in vinegar overnight and you might free them off.

[skinnyman9000 0]

Well the heater worked fine on the way home, so i'd assume that they froze solid over night. I'll take them off and clean them up anyway to see if they behave any better over the coming weeks.

 

Thanks v much for the help 8)

[davidwort 0]

Well the heater worked fine on the way home, so i'd assume that they froze solid over night. I'll take them off and clean them up anyway to see if they behave any better over the coming weeks.

 

Thanks v much for the help 8)

 

I hope nothing froze in your cooling system :shock:

but they may well have stuck with the temp being so cold and everything contracting so much at -10 deg.

[skinnyman9000 0]

Well it was -7 this morning, so possible.

 

I've got the valves off and a whole load of brown gunk piled out when I cleaned them. Now, before I soak them, is there anything I can do to check if they're working correctly?

[dbug 0]

took mine out today and replaced them with 2 later pipes. no heat to lots of heat in 20 mins !!

 

chatting with a VW tech today who told me that they are now obsolete parts to replace and were only fitted as a safe guard to the heater matrix springing a leak ( they got sued by a few in the US when their toes got burnt ) - not fitted to the later ones.

[skinnyman9000 0]

So they're probably not even needed? :lol:

 

Well mine are soaking away now, i'll see how they cope with the cold for the rest of the week once fitted 2moz

[davidwort 0]

Well it was -7 this morning, so possible.

 

I've got the valves off and a whole load of brown gunk piled out when I cleaned them. Now, before I soak them, is there anything I can do to check if they're working correctly?

suck on them :lol:

if you put a finger over the small bore by-pass connection on each, then each one should only blow/suck air through the path with the arrow marked, i.e. in on one and out on the other, block off the out side on either and the small bore exit should blow the air out if left open.

[veedub16v 0]

the permanent solution is to use a heater matrix from a later car that wont explode! GSF supply the one for the audi TT that fits. Then you can delete the bypass valve

[skinnyman9000 0]

Well it was -7 this morning, so possible.

 

I've got the valves off and a whole load of brown gunk piled out when I cleaned them. Now, before I soak them, is there anything I can do to check if they're working correctly?

suck on them :lol:

if you put a finger over the small bore by-pass connection on each, then each one should only blow/suck air through the path with the arrow marked, i.e. in on one and out on the other, block off the out side on either and the small bore exit should blow the air out if left open.

 

 

Well the black plastic one does as explained, but the metal one does not. The metal one lets me suck/blow through any combination of holes. I can actually hear the valve open and close on the plastic one, but the metal one is letting a small amount of air through in various different way. Bugger

[davidwort 0]

Well the black plastic one does as explained, but the metal one does not. The metal one lets me suck/blow through any combination of holes. I can actually hear the valve open and close on the plastic one, but the metal one is letting a small amount of air through in various different way. Bugger

 

I'm feeding you duff information again :roll:

the metal one should indeed work in any direction, It's just cast metal and has no valve in, the arrows show flow from one large end out of both the other large and small pipe, but there's no one way valve so you will be able to blow both ways down it.

[skinnyman9000 0]

Replied to your PM fella.

 

Thanks v much for the help. I'll get them refitted and some new coolant in once i can see my car through the snow again

[skinnyman9000 0]

Well ive refitted the valves and topped up the coolant with some lovely G12 plus.

 

Problem is the heaters are still throwing out cold air. At the minute im hoping its due to the recent coolant flush, and that the coolant system is working air pockets out, as this happened last time i changed the coolant over.

 

However, whilst i was bleeding the system i checked the pipes leading into and out of the bypass valves. The pipes leading into the valves, and the smaller pipe between the two valves was hot, but the pipes leading from the valves through the bulk head were not. Knackered valves?

[davidwort 0]

sounds like the matrix is blocked then, you don't need to loose all your new coolant as it's the high point in the system, I'd probably remove the bottom hose to the header tank, drain down to that level through a funnel into a clean bottle, something like a 2L coke bottle would be plenty big enough, then you can save and reuse what comes out.

Then try to flush and reverse flush the matrix itself by removing the hoses to and from it and wedging a garden hose (not too high pressure) into the bulkhead pipes.

[skinnyman9000 0]

So if i disconnect the valves again and then flush/reverse flush the matrix by running water through each of the pipes that connect into the bulkhead?

 

And then obviously correctly bleed the system again once i put the coolant back in?

[dbug 0]

the valve is designed to close if the pressure in the matrix is lower than the rest of the system

 

the air in the matrix could be triggering the valve.

 

go for the reverse flush ( put hose in the left pipe ) then refill.

 

the valve may no longer be servicable so may be worth just replacing them with 2 pipes and no valves.

 

one other good tip i got from VW was to put upto 3 bottles of antifreeze in the system as it will then help clean all the channels out. then flush after 8 weeks and return it back to 2 bottles and water mix. its a trick they have used for several years

[davidwort 0]

ah, there's more to this,

just spoke to my dad who used to work for a VAG garage,

apparently on the old matrixes the inlet/outlet/cap part of the matrix can bulge away from the core,

result is not visible but will allow hot water to flow into and out of the matrix without flowing through the cores, it won't leak, but wont give you any heat either and yet appears to allow a flow of water into and out of it.

So flushing/reverse flushing won't help in this case, matrix is sha99ed.

[dragon green 5]

It makes sense,mine hasnt got the valve on it,and it wasnt throwing out any hot air.

I gave it a good flush, but it didnt make any difference !

Changed the matrix new years day.

Its well hot, just like it was when i first bought it.

Its better for it to go cold, then burst !

[skinnyman9000 0]

Well I'll flush the matrix 2nite and rebleed the system. If this does nothing then I guess it needs a TT matrix and pipes as opposed to the bypass valves.

 

Yet more spare parts needed! It's a gearbox away from being a full resto!

[skinnyman9000 0]

Something else I forgot to mention.....

 

Before all this I had other issues with the heater. It would kick out hot air which would get colder as the water temp got hotter. Is that connected to what's happening now?

[dbug 0]

Changed the matrix new years day.

 

how old is your motor?? and how big a job is it ??

 

i have read that the dash has to come out - but hope that my 89 16v maybe a little easier than the later ones.

 

skinny - same issue as mine was warm then suddenly went cold/luke warm. i would ditch the valve, reverse flush, 2 bottles of the fancy anti freeze and see what happens. carry a spare pipe to bypass just in case it does burst - so far mine has been good and i spend at least 20 mins a night in stop start traffic. no leak and having to turn the temp down as its too warm in there.