Heater

[mikeeskriett]

Hi,

That's a mk1 Metro heater so '80 - '84 it's the easier of the two to diagnose being simple rod adjustment on the right hand side of the heater and there are less places for the air to escape. The key is to make sure there are no leaks between the blower motor and the heater intake so you're not losing air also make sure the intake blank of the right side of the heater is intact (on a LHD car this blank is on the other side) I have seen them broken or missing before now. Also check whether there is a gap between the bonnet and the blower motor on my convertible there was a reasonable gap so I was getting engine bay smells and low heater flow the easiest test is a thin smear of grease around the blower motor rubber shut the bonnet fully then open it to look for the tell tale grease mark on the bonnet. If there's no grease on the bonnet then it's not making contact so use a section of door rubber around the hole in the bonnet to take up the gap. The other thing to check is if you have good flow from the centre vents (from memory they only blow cold) but poor flow from the demisters may mean that the feeder pipes from the heater to the vents have been pinched where they come up past the dash support by the bulkhead or that the have a poor seal or have come off the vents.

Don't expect miracles but you should be able to have piping hot air but flow will only ever be acceptable.

Cheers,

Mike

[manifold]

....make sure fan is blowing the right way round too! otherwise it will be sucking, not blowing! Not as obvious as it sounds as the vanes are so inefficient.

I have sometimes seen the spade connectors on the wrong terminals on the fan from the resistor.

[paulr]

geoff,

yours is same as mine except in middle bottom mine has 12v power socket rather than your 2 switches and I understand yours and mine is the older sort - have just this evening taken my dash out (again) as following servicing of instruments speedo worked - temp gauge worked but fuel gauge dead and sounds from repairers as though it will have to go back to them for a second attempt - will at least give me a chance to take my heater out and look at the airflow controls and check again that the matrix is unblocked and getting hot - if so my only theory is that the levers must be wrong as air flows nicely but no warmth so am guessing (hoping) that must be the problem - currently am determined to beat it !

logic says to me :-

1 the heater in and out pipes are both hot when the engine is running so that shows there must be water flow through the matrix
2 I have fitted a bleed valve in the top heater pipe and when I open it there is water (hot) so seems unlikely any airlock
3 with fan on and all c ontrols set as your photo above reasonable air flow through screen vents but no warmth

therefore ??????????

can only come to conclusion that either I still have an air lock so that the flow and return is not getting round the h eater matrix itself and/or the air is not being directed through the matrix - any other suggestions welcome


Hans - you mentioned yours when bled is good and hot - anyone else got a working mk3 heater - at least if so will mean should b e able to make it work!!

2 other points - 1 how do you attach photos to your post please?
2 - have printed out gold mk3 convertible build manual and note it says remove spacer piece from below thermostat housing and connect heater flow pipe to a connection mm3 in cylinder head - mine is connected to an outlet on the space piece below the thermostate housing - not sure if that should make any difference - can't see why it should and puzzled as to why manual says remove the space and drill out a separate connection - any thoughts anyone please?

Paul

[mikeeskriett]

Hi,

The Metro has a two piece thermostat housing from the factory the top section feeding the top hose on the radiator and a smaller pipe that links to the top of the coolant expansion bottle the lower section has the original take off for the heater pipes. The lower section is removed to allow the housing to clear the bonnet so a replacement take off is needed for the heater pipe. The solution for this is to drill out the heater tap hole (Blanked on a 1275 engine) and pipe the system up as per a Mini using a Midas produced pipe fitting.

All the adjustments can be made in the car though you may need to fold yourself in half to get in there.

My Mk3 works a treat I used it for work this and it was toasty warm. Mine has the later style heater but the principles are the same.

Cheers,

Mike

[paulr]

thanks mike - good news as means I must be able to get mine to work ! interesting as the thermostat housing seems to clear ok on my bonnet and given that doesn't seem any point in my drilling out and connecting heater pipe to other end of cylinder head - pipes certainly get hot enough so am going to keep on it

[Geoff Butcher]

Before the recent rude interruption we were talking about using the later Rover 100 type blower. Presumably you need the correct resistor to go with it - is speed 3 faster than speed 2 on the earlier type? And don't say 'mine goes to 11'!

[manifold]

I would imagine fast speed (ie 3) is the same as 2 on the older heater. The resister will just be there to slow the speed down.

[Geoff Butcher]

Must be the fastest ever reply to a question!

[manifold]

Ahh thats because I have been a buzy bee today

[mikeeskriett]

Hi All,

I believe the third speed is faster than the second speed on a two speed heater. There are extra taps on the resistor pack and an extra brush set on the blower motor.

cheers,

Mike