radiator and heater problem

I caused myself all kinds of work and money after adding a sealant to the cooling system of a 74 Saab. Not only did the radiator not cool as well after the sealant but the heater core needed replaced too due to the sealant blocking the veins.

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try flushing out the heater core. You might have to replace it if it is solidly clogged. I have seen that happen! AND make sure that the engine gets up to operating temperature.

Not sure if you have what we call a '92 Golf here in the USA or yours is more like a '94 Golf here in the USA.

1992 Golf does not need its bumper removed, only the radiator support. 1994 Golf probably needs its bumper removed.

N.Zar wrote:

The engine does get to operating temperature as usual. I do get some hot air (very little though) when the engine temp. is normal. Does this mean is not solidly clogged?

In order to flush the heater core can I use an ordinary water hose or does it need special equipment with a special cleaner? Should I flush it from both sides?

I guess I should have operated the heater after the use of the sealer, in order for it to circulate in the heater core. I didn't know and I was not told at the time.

As far as the year, the car was delivered Nov1992 therefore is a 1993 (I guess). It was the first year of the Golf III here in Europe and I believe last year was 1999.

TXN for your replies

Ï "one out of many daves"

YES not completely clogged

I would try the ordinary water hose first to test flow through the heater core and run the water hose from both sides, one side at a time though.

Yeah sometimes those leak plugging chemicals plug more than what you want. ;-)

I have still never worked on nor seen/touch a 1993 Golf or Jetta. strange!

Ï "one out of many daves"

LOL.....

I plugged the hose in both sides (at a time ;) ) and let the water run for abt a minute. I think there is a small difference in heat but not quite as before. Is there a chemical solution I can use to clean the heater core by the same method? Would antifreeze make a difference? Thank you again for your reply.

Did the water flow freely and with good volume through the heater core? Antifreeze is not a solvent. You should have antifreeze in your water as straight water does not carry heat as well as a proper mixture. I mean it does not carry heat away from the hot cylinder head properly. Antifreeze also has anticorrosion stuff to protect metals in the cooling system.

I do not know your car but some cars have a valve that controls the amount of water that flows through the heater core. Other cars just divert air past the heater core or not. On a Rabbit there is a valve that controls the water flow through the heater core. It has a cable that actuates the valve by the firewall in the engine compartment. We are talking about a Rabbit aren't we? A real Rabbit from the 70's to

1984, not those relabeled Golfs from this millennium?

The water ran quite freely, and some brown stuff did come out, actually from one side only. The heater worked perhaps a little better than before This morning I repeated the procedure again. The problem now is I don't get any warm air at all. It is certainly worse. As a a matter of fact both hoses that run into the heater core are cold after all other water hoses get hot. Yes I do have the heater on and the fan to medium. It seems I did more damage than good. Anything else I could do? Did I damage the heater core by running water through it?

As stated before 1993 (1994) Golf III 1.4 ltr 80K miles and NO aircondition system

"Jim Behning"

first you have to see if the car has a valve in the heater lines that controls the flow though the core - as you slide the temp. control to hotter the cable opens that valve more till the valve is wide open. Older liquid cooled vw's had that valve, though newer ones went to the door flap in to heater box to control temp. Coolant is always flowing through the heated core in the case of door operated control , even when the thermostat hasn't opened yet. Thus the heater hoses are the first ones to show signs of heat. So it sounds like you have a valve in the heater hoses that's not open/closing properly. Try sliding the temp. control to max / min a few times and listen near the heater box under the dash to 'see' if you can hear the door hitting it's limits. If you can't hear anything down there , my guess is that you have a valve in the heater lines and it not working . the good flow though the core with the garden hose shows you it's not blocked and should be OK.

As Sam mentioned you need to look for a valve on one of the hoses that feeds the heater core. Flushing out some dirty water is fine. The water should have flowed clear after a minute or so.

Cold hoses means that the supply to the heater core is blocked somewhere. As I mentioned the old Rabbits which were called Golfs in Europe had a water flow valve in the engine compartment. You just traced the hoses until you saw it you really could not miss it.

If you do not have a Bentley manual for your car you could try one more experiment. Put the garden hose on the return from the heater core that goes back to the engine and remove the radiator cap. If you see water flowing out of the radiator cap then you know the return is not blocked back to the engine. Now try the supply from the engine to the heater core. You want to pump water back to the engine to see if there is a restriction. If you cannot get water to flow then you know you have a blockage somewhere.

Here's the update When turning the cold/heat knob I notice a slight sound when it reaches the hot side. Very light "klink" like sound. (with the engine not working) I kept turning the knob several times from cold to hot. Then I took the car for a ride and after 20 minutes or so when engine temp. got up to normal I stopped and checked it. Both hoses to the heater core were very warm. The heat works again, not as hot as it should be but I can live with it. I guess the problem as you said is the valve that controls the flow. The sealer I used, must have done the damage. My next quest (you have propably figured out by now I am a newbie with working on the car) is to flush out the radiator and replace the water with antifreeze (or

50/50). Can you please advise the steps involved in doing this. Just for the record, I read in some posting on the net that someone uses white vinegar to clean out his car's cooling system. Lets the engine run hot with it, leaves it overnight and then flushes it out the next day. Can this really work? Or will I start a fire ;)) Thank you again all for your help. You guys are great.

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