Blowing cold.

Hi Everyone,
It's that time of year, at least the house heating fired up okay lol.

The fan is only blowing cold, I have hot coolant to the top pipe that goes through the bulkhead but not on the lower pipe so guessing either a blocked/knackered matrix or (hopefully) just an air lock?
I've read that to clear an air lock, disconnect the cooling fan and remove the rad cap and run it until it boils over then refill cooling system, can anyone confirm or warn me off doing this?
Many thanks
Pete

Try manual moving the heater control valve under the bonnet. It could be that the wire has snapped or come off and isn't moving the valve

Ian

I will give you 2 pieces of Advice.

Remove the upper and lower heater hoses off the inside of the engine BAY.  
With hose pinch pliers pinch the lower hose off.
Use CLR about 1/4 cup poured in to the upper hose and let it work for about 30 minutes.

Using a garden hose unpinch the lower hose and run water in the top hose.  once it runs clear, repeat the process from the bottom hose to the top, do this about 4 times and you should have an opened clear heater matrix.

No go buy a Porsche 944 (1988) Heater Valve they are nearer to the Original design of the Vane type and are easier to open and close.

Be sure that you point it the right direction.

Mfg Part #:94457208502

While the cable issue with it not being positioned correctly, is usually the cause, It could also be that your valve is broken internally, and lets face it they are a PITA
Two of the last ones I bought leaked at the same place, and I had to Beef the new ones up until I found the Porsche Valve what operated smoother.

Cheers guys. The top hose is hot at the bulkhead so guessing that means the valve is okay/open?

Whats CLR Brian?

Calcium Lime Remover  CLR….

Valve Break internally and or they leak and blow apart.

Here is one that blew apart on me:


here is where 2 new valves started to leak on me, and on the 3rd new valve I beefed it up.



https://volkswagenownersclub.com/vw/showthread.php/91714-Those-Plastic-Heater-Valves.....?p=644178#post644178

I've not heard that method for clearing an airlock but it doesn't sound right. Yes, Mk1 Golfs can be awkward to bleed but it just takes time and the right method…ie you bleed off the air from the highest point of the cooling system.

I can't help you much more because my car doesn't have the same setup, it doesn't have an expansion tank (its 1981).

Not sure how relevant it is but I've seen it on other FWD/small cars, where the bonnet is quite a slope so the components forwards are lower down - one tip is to raise the front of the car HIGH and bleed it (from the highest point).

Mine does have an expansion tank either (1.8T 20v )

The easiest way to prevent the dreaded air lock is to
drill a 1/1 or 1/8" hole in the t-stat lip.



The way I did it for years is to open the heater valve remove the expansion tank cap.
Fill the Block with a/f mix at the front head outlet.

Fill the radiator. from the upper hose,  add 1/2 of a/f to fill the expansion tank 1/2 way.  Start the car Heater fully hot, and when the t-stat opens your expansion tank will drain out, top it off and cap it and you should bee good to go.

 I personally have Never had the dreaded Air bubble from Hades I guess I was either lucky or filled things the right way that is 1/2 of it from the block and 1/2 of it from the radiator, unlike some of the never VW's and or Honda, Toyota and Nissans that I have owned that had a bleeder port on the t-stat housing.

I am of a thought that your heater valve may be broken internally (which I have had), or that your heater Matrix is plugged and not allowing water to circulate.

If you or your previous owner has had a A/F to Oil intermix via the Oil Cooler leaking or a blown head gasket, and yo are using the Pink A/F then a little oil can Curdle and Plug up your Matrix. Regular Green a/f and oil intermix doesn't cause this condition.

If your cable isn't situated correctly, then you may not be opening your heater Valve fully, and the upper hose will get warm as the hot water is sitting there not going anywhere….

Flushing out your Matrix is easy and Cheap to do,  You don't loose that much coolant if you use hose pinch pliers on the hoses.  I would strongly urge your to replace the Lower Heater hose butt-to-butt connector that is plastic with a Brass Hose mender 5/8" in diameter… Because that plastic barbed hose splice on the lower hose will be a time bomb once you remove the heater hose to it.

A normal GOLF/RABBIT/Cabriolet heater matrix when functioning properly will BURN your Hiney out of the car.

The newer style Porsche Valve is easier to move on the Cable and controller that the older ones originally had versus the "re-designed" newer square types.

 

Pete M said

Mine does have an expansion tank either (1.8T 20v )

I don't know what your setup is then, can't really help further. But the basics remain…..get everything flowing, get the air out the highest point in the system.