No heat at heater outlets mk1 fhc
Discussion
Hi,now winters here after the cracking summer I now need demist/heat for the winter daily commute.Whilst heater has never been great it's normally just enough to get by.Took car for MOT a few weeks ago and forgot to tell the mot guy how to switch on manually the electric fan ( as I wasn't expecting car to get too hot) anyway did MOT (passed)he parked it back outside and did the paperwork.As I was last of the day the place was closing as I went to the car,it wouldn't start -(never not started before)after doing some basic checks it was then I noticed temp gauge was off the scale.!! The mot guy was no help and went off home.Decided to let it cool down and hey presto it started again.No problems since apart from heater.Ran her up today from cold till passed the point I would normally switch on electric fan( note still has original engine fan as well) no leaks found all hoses ok.Radiator top / bottom hoses hot.thermostat housing hot,hose up to expansion tank starting to get warm.Hose to heater slightly warm out of thermostat housing rest of hose to interior valve cold.return hose back from heater cold.This has bleed point in the line and when cracked waters there.What could problem be - thermostat? Seems to be doing what it should ,airlock in hose too heater? blocked heater matrix?When system has been apart how do you ensure water in matrix and air out as this seems highest point in system -can you get to connections at matrix without removing dash /heater box ? Thanks dave
Hi Dave
The matrix should be accessible by removing the centre console and left and right under dash trim.
I disconnected my heater hoses in and out on the 280i as even in the coldest of days it was warm from the engine heat travelling up the transmission tunnel.
Once cold..remove expansion tank cap, start engine and rev gently with the throttle linkage...you should see a flow in the tank..however if you have the early overflow from the rad going to the floor then you may not see this.
To be fair the heater system is not that good at the best of times..it may be fine..just pants...you can feel the matrix once warmed to see if that is getting a flow...
Ziga
The matrix should be accessible by removing the centre console and left and right under dash trim.
I disconnected my heater hoses in and out on the 280i as even in the coldest of days it was warm from the engine heat travelling up the transmission tunnel.
Once cold..remove expansion tank cap, start engine and rev gently with the throttle linkage...you should see a flow in the tank..however if you have the early overflow from the rad going to the floor then you may not see this.
To be fair the heater system is not that good at the best of times..it may be fine..just pants...you can feel the matrix once warmed to see if that is getting a flow...
Ziga
Hi sorry to hear about your issues with the heater.
Did the car overheat before without the extra cooling fan ?
The reason I ask is that if the mot tester does what they normally do and leave it running so that when it comes to the emissions test it is nice and warm and makes it more likely to pass.
The reason I say that is that when you went to start the car it was red hot and you had to wait for it to cool down then it may have overheated and cooked the head gaskets.
A leaking head gasket gives some of the symptoms that you describe (ie no heater output despite how many time you try and bleed it)
I would suggest getting it to you local garage and get a sniff test done to see if there are any combustion gases in the water that would rule that out.
Mike
Did the car overheat before without the extra cooling fan ?
The reason I ask is that if the mot tester does what they normally do and leave it running so that when it comes to the emissions test it is nice and warm and makes it more likely to pass.
The reason I say that is that when you went to start the car it was red hot and you had to wait for it to cool down then it may have overheated and cooked the head gaskets.
A leaking head gasket gives some of the symptoms that you describe (ie no heater output despite how many time you try and bleed it)
I would suggest getting it to you local garage and get a sniff test done to see if there are any combustion gases in the water that would rule that out.
Mike
Kudos for driving in the winter. I have even more need of the heater this time of year as I'll be driving with the top down.
The heater box in earlier cars is pretty poor but if you haven't got any hot flow that won't help. Before trying to take the box out which is a big job, try flushing it out in both directions - take off the hoses at the engine end and connect a hosepipe. Take note of what crud comes out.
The other thing to check is the hot water valve operated by the heater control - try opening and closing it during the flushing process multiple times in case any crud has built up.
The heater box in earlier cars is pretty poor but if you haven't got any hot flow that won't help. Before trying to take the box out which is a big job, try flushing it out in both directions - take off the hoses at the engine end and connect a hosepipe. Take note of what crud comes out.
The other thing to check is the hot water valve operated by the heater control - try opening and closing it during the flushing process multiple times in case any crud has built up.
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