Heater not working 1980 340 Vario

Post by **Batteries included** » 29 Dec 2007 06:07 pm

The heater shows no signs of getting hot in my 340; the flow pipe from the water pump only gets slightly warm near to the pump, so nothing is flowing. Bleed valve in heater plenum chamber spews out water when opened. I see a thermostatic valve on the top of the transmission tunnel on the passenger side which is being activated perfectly by the Bowden cable from the heater tempertaure control. Do these valves give problems? Thought I'd seek advice before disconnecting hoses and gently applying water pressure from a hose pipe. I guess blocked hose or heater matrix or faulty valve. Car lived most of its life in South Africa so I guess the heater was never missed! Would appreciate help, please. Cheers, Alex.

Post by **Chris_C** » 29 Dec 2007 06:47 pm

Sounds like you checked most of it, the most likely thing normally is the bowden cable screws up. As you say the hoses only get slightly warm (tbh, they shouldnt get that hot) where abouts is the dash water gauge sitting?

Also, I'm sure you have, but just check the water level is up

The heater matrix is at the top of the system, and first thing to normally go. Luckily the 300 system is self bleeding though!

Post by **2 Fast 4 U** » 29 Dec 2007 07:15 pm

maybe the heater core is full of junk, the only way to find out is to take the hoses off at the waterpump and rince the hoses and heater with the garden hose

Post by **pettaw** » 30 Dec 2007 06:01 pm

Sounds to me like the system is clogged up with junk, be careful though, its quite possible that the junk is clogging up the matrix is also keeping the water in there

flush it through and then put a good flushing agent in too. I can't remember what the procedure is for bleeding those early ones but I have a funny feeling you warm the car up first so its all open and then you shut the car off and gently bleed it out.

Post by **morgan105** » 30 Dec 2007 10:14 pm

I know this could be to easy a idea but is the car temp warming up? Is it possible that someone may have removed the thermostat so none of the coolant is getting hot but only warm, it was in a warm country before you got the car so it may have been taken out and not replaced or the thermostat may be getting stuck open.

Failing that I would also go along with the others and say the system is clogged.

morgan105

Post by **SteveP** » 31 Dec 2007 01:04 am

Sorry as not to help, but sounds like an interesting car.... got any pictures?

Post by **foggyjames** » 31 Dec 2007 01:58 am

Hearing what happens to the engine temp gauge would be interesting. Bearing in mind where the temp sensor is on a B14, would it read falsely cold if the water pump was failing? The top hose really should get good and warm (eventually), even with no thermostat in there.

cheers

James

Post by **morgan105** » 31 Dec 2007 08:19 am

Water pump went on wifes car a while ago and when that went the temp gauge went right up off the scale in a very short time. With the pump working but no stat fitted you would be lucky to even get to the first marker point on the gauge while sitting in traffic and if you were driving it barely moves out of cold (all tried and tested).

I have everything fitted as it should be now in the wifes car after tests, new pump, new radiator (wider version not the thin original type), new senders, fully flushed and cleaned system. The only difference now that I have found is it runs slightly cooler due to the wider radiator.

The reason I was suggesting about the stat was because of the tests on my wifes car as hers is a 340 and because the stat has just given up the ghost on my car and the heat out of my heaters is very poor at the moment but used to be great before the stat went. Will be replacing it today though before the weather freezes again.

morgan105

Post by **Batteries included** » 06 Jan 2008 06:23 pm

Thanks all for your helpful advice. I've had various hoses off the car this weekend and flushed out with water. Heater was perfectly clear but found a blockage at the water pump where the heater return hose goes into a pipe under the pump. Gave the radiator a flush as well and added new anti-freeze. We now have a working heater! Cheers Alex