16 replies to this topic

[minilee2k10]

1986 mini city e 998 standard car

hi, i have recently decided to sort my heating out ( its never worked for 2 years) i fitted a new heater unit complete with new matrix and a new heater tap but the heater still does'nt heat up unless i rev the engine or am driving fast then as soon as its idling it goes cold again, (definetly not an air lock) i think it may be the water pump is clogged or is this just how the heaters are?

it got me thinking would it be possible to fit a 12v inline water pump (off ebay for around 20 quid) and fit it between the heater tap on cylinder head and the heater, that way there would be a healthy flow of hot coolant to the heater even at idle

does anyone think this would be possible or even a good idea?

any opinion would be appreciated

thanks

[Spannermanal]

My thoughts are that if the water pump is not pushing water around the heater, is probably isn't pushing it around the engine too, which is bad news. could have a blockage in the system - I have cleared these in the past by using a hose pipe - but don't turn on too high as water pressure in mains could cause damage.

[pikey7]

I would think that if it's done that for 2 years then it's not a water pump issue or you'd have changed the engine by now too.

have you ever used anything like bars leak in there?

Give everything a good flush out. engine, heater, everything. Get the hosepipe down every (water) pipe you can in the engine bay, get some fresh water in there, run it up to a nice warm temp, and then flush it again it again, but obviously use antifreeze this time.

[1984mini25]

definetly not an air lock

I think you WILL find it is.

Try running the car stationary at a fast idle, with the radiator cap off and the heater on full, until the engine is unto normal temp when the thermostat opens and the heater blows out warm.

[mikey72]

On ours, the little pipe from the bottom hose to the heater pipe was nearly blocked solid, I had to take the pipe off and poke it though.

[minilee2k10]

thanks for the fast replies

i tried to run the engine today upto normal temp, but even after nearly 40 mins it was still only just above the blue on gauge, i think its because of the cold weather, the thing that makes me think the water pump maybe blocked is when idling for very long periods the engine gets very hot (about 3 quarters on gauge ) but then i rev it up and the gauge drops rapidly indicating that the water pump needs high revs before it works properly?

i did use rad weld about 18 months ago? its just puzzling that if it is the water pump it would over heat rapidly if anything its very slow to warm up?

[mikey72]

Slipping fan belt and a thermostat stuck open?

[mike.]

It should warm up enough to open the thermostat in around 10 minutes even in cold weather. I'd check you thermostat and while your at it, just replace it with an 88 degrees 'stat.

[minilester]

It should warm up enough to open the thermostat in around 10 minutes even in cold weather. I'd check you thermostat and while your at it, just replace it with an 88 degrees 'stat.

..that what i did for the winter.. now it blows lovely and warm/hot after 10 mins of engine start.. think i'll also buy a nice low thermostat for the summer too, its not like it hard to change them..

[minilee2k10]

i drained the coolant again today, from inside the car heater hoses, as i can't get bottom hose off the rad, the coolant is jet black! anyway i topped up with coolant again and tested heater and after about 30 mins the heater was blowing nice and hot even at idle! so i thought WOW ive fixed it, but then left it an hour or so and tried it again, and its gone back to blowing cold again! aaaarrhh! i looked in the radiator when engine running from cold and i can see the coolant flowing around, would this indicate the thermostat is stuck open?

other than that i think the whole cooling system may need replacing to get it running perfect!

[mikey72]

Sounds like it just needs a decent clean out first.
Take the pipe off the heater control under the bonnet, put a hose pipe in the radiator, and flush until it flows clean. Alternatively lift and lower the hose from the heater to flush or backflush, until it runs clean both ways.

[pikey7]

indeed mikey. It does sound like you moved the blockage and it decided to move back. You need to flush it, under a bit of pressure, properly. get that crud out of there.

[minilee2k10]

i will try to flush out tomorrow, i have ordered a new 88 °c thermostat as i don't think the over cooling is helping! you don't realise how much you need a heater in this weather!

[maccers]

I recently tried to fathom out why my heater was also not working. After doing a winter water change and thermostat earlier in October, I rebuilt the heater using a new matrix, new foam etc. Made sure the heater motor was blowing and not sucking air out of the car by connecting just the motor up (it has rotation arrows on the fans anyway).

To check the water was flowing from engine to heater, I removed the matrix once again after rebuilding and nicely sealing the heater unit, used fish tank Ehiem hose thats green, but lets you see through it to make sure the water is flowing. All ok, no air locks, heater matrix getting red hot, can visually see the water going in, and going out, while holding the matrix in my hand until it got too hot.

Re-assemble and seal heater unit, connect back all original hoses, matrix gets hot, turn blower on and nothing but cold air.

I figure its just too cold recently, so disconnected the fresh air hose and blocked with a Waitrose pasta sauce pot, it has the exact size! I get some heat form it, but as soon as blower is turned on, cold air.

Luckily I dont use the car much, but wanted to get it set up correctly.

[tonym]

I recently tried to fathom out why my heater was also not working. After doing a winter water change and thermostat earlier in October, I rebuilt the heater using a new matrix, new foam etc. Made sure the heater motor was blowing and not sucking air out of the car by connecting just the motor up (it has rotation arrows on the fans anyway).

To check the water was flowing from engine to heater, I removed the matrix once again after rebuilding and nicely sealing the heater unit, used fish tank Ehiem hose thats green, but lets you see through it to make sure the water is flowing. All ok, no air locks, heater matrix getting red hot, can visually see the water going in, and going out, while holding the matrix in my hand until it got too hot.

Re-assemble and seal heater unit, connect back all original hoses, matrix gets hot, turn blower on and nothing but cold air.

I figure its just too cold recently, so disconnected the fresh air hose and blocked with a Waitrose pasta sauce pot, it has the exact size! I get some heat form it, but as soon as blower is turned on, cold air.

Luckily I dont use the car much, but wanted to get it set up correctly.

hello im finding the mini heater not so good even when working properly but just about does the job but need about 5 miles to warm up they havent improved much over the last 40 odd years they werent good then . but as i say just about do the job..tonym