Heaters Blowing Cold air! Head gasket or Heater Valve?

[yellow-160]

Ooooook! Got a 89 Mk2 Gti and when i put the heaters on they dont get hot! had a few people telling me the head gasket is gone and a few others telling me theres some kind of valve that is a common problem!

Any help would be good!

Engine starts and runs fine, no loss of water (does boil tho if u leave cap off!) no gunk in oil and no oil in water!

Totally lost with this one! have replaced the thermostat, and checked the heater matrix and doesnt seem to be blocked! theres some silver thing just before the bulkhead that connects with a little hose to another part of the matrix but no idea what the hell it is!

PLEEEEEEEEEEEEEEEEEEEEASE Help ME!!!!!!:aargh4::aargh4::aargh4::aargh4:

[big_tom]

Sounds like a broken heater matrix mate. They don't have to be blocked to fail. If the blowers still blow air but don't get hot, then thats what it is. When you replace it, go for a mk3 unit, much more reliable, available new for not that much.

[yellow-160]

am i getting mixed up? where is the heater matrix located? behind the bulkhead? or is it the one that runs around the engine! i stripped the engine cooling system out but never touched anything behind the bulk....

:1zhelp::aargh4::1zhelp:

[big_tom]

it's the cabin side of the bulkhead, behind the dash. If you have a haynes manual it'll tell you in there.

[yellow-160]

Checked the heater matrix and water flows in and owt the bulkhead happily... theres a silver valve just before the bulkhead which the water doesnt seem to pass through when it heats up....

took it out and it doesnt seem to be blocked but as soon as i put it back in and the engine warms up the water flows through the small hose but doesnt go through the bulkhead hose!! im rather lost

[Benignus]

You probably need to replace the bypass valve. Take it off and flush it out and see what happens. If it still doesnt work get a bypass valve from a scrap yard.

[flymofred-2008]

hello I have '86 8v GTI, same one for 15 years. I had the same problem someone on this forum gave me the part no. for the replacement valves (metal in plastic out) and got the main dealer price bang on.

It comes with the by-pass pipe connected and even a separate bag with new hose clamps. my local dealer said that this part has now been deleted, but fortunately sourced one from from another VW dealer.

For myself I'm not that worried as I feel that this one ought to see me out. Oh and the heater,magic, back to making your fingers hurt if you hold them in front of the centre outlets.

flymofred

[flymofred-2008]

Hi i just found the original post it's 28/12 by Paull, and Crasher has all the info in his reply

If you you read this Crasher Thanks

flymofred

[yellow-160]

Thanx for the info, the metal bypass valve is jammed shut, I rmoved both valves and fitted 2 22mm copper pipes instead, car is running great now and heaters are also working!!! :biglaugh:

Might invest in the new valves at somepoint but until i get car through an mot no real point! still got loads of work to do on it!

Just one question... if you start the car with the header cap off should it boil??mines boils over after 3-4mins but temp sits at normal point and if you have the cap on it doesnt do owt!

[Crasher]

You MUST either fit a new by-pass valve set or a new GENUINE VAG dealer supplied late Golf 3 heater matrix. An impromptu 100 degree centigrade foot spa of water and antifreeze on the motorway could ruin your day and the day of anyone near you. Excruciating pain, high speed and an instantly totally steamed up car do not make a good threesome.

[Smutts]

The exploding heater matrix and siezing fan motor were made in France. Go figure.:p What other bits of the MK2 are French?:1zhelp:

[Crasher]

Valeo France made nearly all the heater box systems for the Golf 2 and 3 although some were made by their South African operation.

[GTI Trim]

This happened to my Mk 8v gti recently. After flushing through the matrix with water via a hose pipe left on for 5mins or so, all worked fine.

Also you can reconnected the matrix with a new length of suitable hose. The inline bypass valve doesnt need to be in place - they tend to stick closed so I chucked mine in the bin. Mines working perfectly (can send a pic if you dont believe me - I must admit I was concerned at first).

Best of luck

[Crasher]

Removing the safety check valves is absolute crass stupidity and I really feel that you should delete that remark immediately. The only time they can be removed is when a new, genuine VW, updated late Golf 3 matrix is installed. The inline check valves were fitted as part of a safety recall to prevent the heater matrix from exploding during an engine overheat, so dumping boiling coolant all over your feet and spraying at your face through the face vents. Don’t dismiss this, I have seen it happen and it has happened to me but I was lucky, the lads in a car queuing in a car behind me for a VW show in Holland were very badly scalded on their legs and feet. Take my word for it, boiling (around 105°c) coolant is extremely painful, one incident with it put me in hospital when it sprayed in my face.

[onzarob]

This happened to my Mk 8v gti recently. After flushing through the matrix with water via a hose pipe left on for 5mins or so, all worked fine.

Also you can reconnected the matrix with a new length of suitable hose. The inline bypass valve doesnt need to be in place - they tend to stick closed so I chucked mine in the bin. Mines working perfectly (can send a pic if you dont believe me - I must admit I was concerned at first).

Best of luck

As crasher has Said the bypass was a retrofit/recall by VW as it is a serious an d real problem.

I decided to leave it in as a warning, some advise does not always make sense;)

[Smutts]

You can just picture it. Really hot summers day, 110mph thrash on the motorway. Cabin full of boiling coolant, badly scalded driver, windscreen instantly fogged up, that's if you can still see, armco trees sky etc, etc, etc. You and your passengers would be dead chuffed to have saved £22.45.:1zhelp:

[onzarob]

You can just picture it. Really hot summers day, 110mph thrash on the motorway. Cabin full of boiling coolant, badly scalded driver, windscreen instantly fogged up, that's if you can still see, armco trees sky etc, etc, etc. You and your passengers would be dead chuffed to have saved £22.45.:1zhelp:

Very well put:beerchug:

[yellow-160]

Until the car goes back on the road il be leavin the 22mm copper pipe in, Car doesnt have a clutch yet so no really worry!

if the valves were fitted as part of a recall they aint very good are they as most people you speak to say they alwys jam closed!! it would be my luck they wouldnt bloody close atol whne i needed them!!:aargh4:

[Crasher]

At least they aren’t very expensive.