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MG MGA - Not much heat

Hi,
Heater not throwing out much heat even with blower on. New heater valve, all clean in cooling system, both heater pipes are getting hot. Heater fan? It's working but maybe not enough. Can't think of anything else. Any ideas please

Many thanks,
Phil
p parmenter

Is it the heater temperature or the air flow that is the problem?

I don't know what the temperature is like in East Sussex at the moment but the incoming air is likely to be pretty cold so the heater will struggle.
Malcolm Asquith

If both heater hoses are hot, and the blower is running,but the air output is barely warm, then part of the heater core is clogged (but not all of it).
Barney Gaylord

Mouse nest ?
Art Pearse

Motor running backwards?

Steve
Steve Gyles

Thanks for the tips. Can the motor run backwards? Is it actually necessary to remove the heater box to get the core out?

Phil
p parmenter

The original heater motor will run the same direction even if you switch the power and ground wires, which is why the motor leads are both black. To make it run backward requires switching field wires inside the motor case.

Trash in the air duct or inside the heater box is a possibility if the air flow is nearly nil. Yes you have to remove the heater assembly from the car to remove the core, but it not such a big chore in the MGA. To start with, you can remove the air inlet valve and pipe (only three screws) in front. Then undo the collet nut to with draw the blower wheel. That may give enough access to clean out most trash that may have accumulated inside the box.
Barney Gaylord

I thought MG heaters were ornamental.
Bill Haglan

No Bill, definitely made in Britain!
N McGurk

Phil, have you tried sitting on the passenger (left-hand)side? My wife and I took part in the Norfolk Riviera run on 28th December, it was cold and pouring rain all day, and despite the hood being up and the heater blowing, I was freezing and my hands were blue with cold. I asked my wife if she was cold, "no" came the reply, "it's lovely and warm on this side"!
Lindsay Sampford

Well, she had a centrally heated floor from the exhaust pipe! That was the only source of heating on my MGTC. The temperature differential between the 2 sides was very noticeable.

Steve
Steve Gyles

No it's not warm on either side. Just a trickle of warmish air coming through the heater outlet although as I say the heater hoses are hot. When I get time I will take the heater box out and check for any obstruction etc.

Phil
p parmenter

I just rebuilt two of the heater fans. Either the brushes can be worn out or the bearings might need to be oiled.

Very easy job - once you pull the whole assembly, you can refurbish the motor in 15 minutes.

Clean, change the brushes, sand or file the commutator, and reassemble.

The fan now turns vigorously... very happy!

JIM in NH
AJ Mail

Thanks Jim - I'll give it a go

Phil
p parmenter

I fitted an uprated heater matrix and fan when rebuilding my heater. Heater matrix has more tubes and finny bits plus the modified fan, which fits the standard motor, gives more blow.
Andy
A J Dee

Andy,

Is the heater any better as a result of the uprated parts?

John
J Bray

Andy again,
Where did you buy the uprated parts?
Phil
p parmenter

MGOC do an uprated matrix and it would appear did an uprated fan and motor too:
http://www.mgocspares.co.uk/acatalog/MGOC_Spares_HEATER__MGA__118.html
N McGurk

One other thing. There is an inlet screen (or there is supposed to be) where the inlet duct and damper are. Leaves and such can get stuck on this screen and reduce air flow. Stick your shop vac in there and see if that helps.

With the fan running, your hand should "suck" up to the inlet duct if you cover it with your palm. If not, then something is wrong with the fan.

My newly rebuilt fan blows quite a lot of air.

JIM in NH
AJ Mail

Just to repeat what i said in an earlier thread . My fan will run both ways . If you have an original motor it will most likely have wires coming out of the motor that are soldered in. My motor has 2 spade conections sunk into the housing , this will run backwards if the wireing is transposed.
Also mine had a plastic fan fitted and it really does pump the air out now.
Wasnt somebody going to fit a MGB plastic fan to the heater and see if it improved the airflow ?

Roy
R Mcknight

The uprated parts did come from the MGOC.
Andy
A J Dee

Fit one of Lindsay's blowers in the trunking. That should get the air moving!

Actually, I might just try that. I have not had any need for the one that I installed on the other side for carb cooling.

Steve
Steve Gyles

Andy, -- Do you have part numbers for the uprated heater parts from MGOC? I looked at their web page, and it lists standard part numbers, no mention that I can find of any uprated parts. The reversible motor may be a later MGB part. Also is the plastic fan designed to turn the correct direction for the MGA heater box?
Barney Gaylord

Has anyone actually tried a bilge blower fan in the heater trunking? I have seen mention of it in some of the archived threads.
Phil
p parmenter

Barney,
The uprated heater matrix is listed as F216 and an uprated heater motor and fan as F217 - numbers 22 and 23 on the heating and ventilation page.

Phil
p parmenter

Got it. Looks like the uprated motor and fan is not available now.
Barney Gaylord

Barney,
on MGOC the "heater Motor+Fan" are now incorporated in item F216. If you press "more" a new window popup and you can read the info.

Giovanni
Giovanni Delicio

I know, but there is no link to buy it.
Barney Gaylord

I got the KGB blower but it is set up to go the wrong way.

Jim in nh
AJ Mail

No point in moving lots of air if you do not have the capacity to heat it. The major problem ( for the cold UK climate) is the heat output of the heater matrix.
Once the car is on the move the air through the heater should be acceptable - assuming you have both pieces of trunking in place !!
A J Dee

Hi,
Spoke to MGOC spares. They do sell an uprated motor and fan (the motor is 2 speed but can obviously be wired in single speed). They say they do not sell an uprated fan on its own as it wouldn't fit the standard MGA motor. Has anyone obtained one of these from elsewhere?

Phil
p parmenter

Many years ago I bought an uprated fan from Bob West who at the time said he only had limited stocks (this may have changed now). The fan sends a large amount of air through the system but as AJ says its dependant on the heat flow from the matrix. If the matrix is not 100% you just get a lot more slightly cooler air.
J H Cole

Thanks for that JH - I'm going to get an uprated matrix and I'll try Bob for the fan

Phil
p parmenter

Barney, see here:
http://www.mgocspares.co.uk/acatalog/MGOC_SPARES_HEATER__MGA__118.html

On this page there is a window that says "Add to cart",

If you click on it a new window opens and you may order the part.

Cheers

Giovanni
Giovanni Delicio

No such link. I'm interested in items 22 and 23 at bottom of the page.
22 Matrix - Heater High efficiency F216 has a link.
23 Heater Motor and Fan uprated F217 does not have a link.
This looks like the uprated motor and fan is not currently available.
Barney Gaylord

Barney,
See my note above. MGOC say they do have an uprated motor and fan.

Phil
p parmenter

Then they should fix their wen site, because there is currently no way to order it on line. When the web site says it is not available, I'm not likely to make a phone call to ask.
Barney Gaylord

This thread was discussed between 17/01/2013 and 24/01/2013

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This thread is from the archive. The Live MG MGA BBS is active now.