Interior Heater Not Working

[Dave]

Dear Members,  I've got a 1990 126 BIS and have awful overheating problems.  I've installed a new thermostat even though the car didn't have one.  This doesn't seem to matter as the car overheats with or withoutn the termostat.   However, the interior heater doesn't blow hot or warm, not even luke warm.  Nothing.  I removed the radiator (the small one serving the interior heater under the bonnet) and disconnected the pipes and a load of brown water came out and I've flushed the enitre system but still nothing.  The water just drips out of the pipes so wondered if anyone knew a way to flush the pipes through or how to solve the problem.  With the heater working this might help with the overheating problems.

[dajwid]

Welcome to the club.

Sorry I can't help as have aircooled, but I am sure one of the Bis owners will be along soon.

[ChrisRLewis]

Possibly needs bleeding?
http://club126uk.co.uk/smf/index.php?topic=3138.0

[Dave]

Thanks for the tip re bleeding.  I've followed the instructions and a whole heap of brown water came out of the bleed pipe!  I refilled the radiator and followed the instructions again.  Water ran clear and very hot but heater still blowing cold and car overheating. 

Any other tips appreciated.  Very frustrated now!

[ChrisRLewis]

Most Bis owners remove the thermostat because it causes so many problems.  Try removing the thermostat and re bleed the system.

Perhaps the system is clogged and requires an additive to clean it out, especially since you are saying that there is still a lot of gunk coming out?  It could also be the dreaded bis head gasket problem which is causing the air lock.  May also be the heater control not working?

But the first step would be to try bleeding the system without the thermostat.

Dont forget to use an inhibitor when the cooling system is working ok.

[Dave]

You can probably tell I'm a bit dim when it comes to cars!  The car doesn't have a thermostat.  I'll try it again during the week.  Lastly, what's an inhibitor and how do I know if I have one?

Apologies for all the questions.

[Rusty's Uncle]

Sounds like you may have at least one blockage there or the brown water could indicate that the car has been overdosed by some sort of sealant, possibly to overcome a blown head gasket. When you say overheating , what are the symptoms ? If the system wants to blow out the water when running it could be a blown head gasket pressurising the cooling system. I would be inclined to remove the thermostat , fill the cooling system to the brim after bleeding and see if you get any bubbles .

[ChrisRLewis]

Inhibitor is an additive to prevent corrosion in the cooling system.  Most antifreeze solutions contain an inhibitor of some kind.
It is also best to use de-ionized water instead of ordinary tap water or alternatively use a ready mixed antifreeze/water solution.

[Dave]

I have removed the thermostat.  The car heats up quite quickly and tends to stay just below the red line on the gauge.  The radiator cap also steams and hisses and the whole thing gurgles like its going to pop.  I'll try the bleed again.  The oil is fine, no water in it so can't put the head gasket as a failure.

[ChrisRLewis]

The oil is fine, no water in it so can't put the head gasket as a failure.

Gasket may have blown between the cylinder(s) and the water channel only, if this is the case there will be no water in the oil.

[bis13]

squeeze the water pipes that serve the radiator when the car is running, if they are rock hard then you have an air lock somewhere in the system which could mean a whole heap of things, try this first and we will progress when we know the result.   

[Dave]

I've squeezed the pipes and they are all soft.  I'll retry the bleed tonight to see if that helps.  Don't know if this helps as well, but when the car is hot, water hisses from the radiator cap and steams quite badly.  When I release the pressure from the cap, the car gurgles quite badly.

Thanks for all your suggestions so far.  It is very kind of you all to respond.  Sorry for being a bit of a dimwit but this is my first old car if you know what I mean.

[Rusty's Uncle]

Head gasket for sure . Where are you in Bucks by the way ?

[Dave]

I thought if the head gasket had gone there would be water in the oil?

I'm in one of the villages just outside Buckingham.

[Darrell]

Has anyone thought that perhaps the flap that directs air from the heater matrix into the car may be stuck?
If the cap hisses it may be knackered cap.
May also have no water flow (knackered pump)
Get Rusty to look at it for free