MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - my cooling system flow?

Hi all,
I'm installing a new Mojave heater today and I'm confused about my own cooling system. It's been 6 years since I did a resto on the car ('50 TD) so I don't remember the flow! I've looked for a TD flow diagram with limited success.

1. From what I can remember the upper pipe (marked -->) comes from the heater, the lower goes to the heater (<--). I drew the arrows today but I'm not sure they are correct. What do you think? Which one should be hotter to the touch?

2. Is the valve in the open or closed position? I would say it's open? I would close it if I no longer wanted heat, correct?

3. How does the thermostat figure into my system?

I know this sounds dense, but I've been wrestling a new 5 speed installation for weeks now, so I am a little dense!
Thanks,
Ed





efh Haskell

Ed, see http://www.ttalk.info/XPAG_Cooling_System.htm for Gene Gillam's description. Bud
Bud Krueger

Ed,
Here are 3 images I found from some work I did about 4 or 5 years ago.
Mort

Mort 50 TD

next

Mort 50 TD

last

Mort 50 TD

Bud, thanks. That is an interesting article which shows how the water travels through the block and the head. But it doesn't address my 3 questions above about the heater.
Thanks,
Ed
efh Haskell

Mort, thanks, this helps a lot! I notice you have the same Mojave heater I'm now installing and it's hanging upside down, just like mine will be! So my question to you is the top hose in your picture the "IN" hose with hot water and the bottom one is the "OUT" hose? Is that correct?
And would you happen to have one of those great drawings showing the heater hoses in line? Great artwork!
Ed
efh Haskell

Those drawings also show why the worst place to get hot water for the heater is from the back of the head.
Gene Gillam

Eth,
if you have the original type thermostat, when the engine is up to temp the by-pass is closed shutting off the heater supply. If you have a modern stat all is OK.
Ray TF 2884
Ray Lee raybar2(at) tiscalidotcodotuk

Thanks guys, but can anyone answer my first two questions in this post?

Gene, my heater hookup is in the front. see the picture.
efh Haskell

the one from the thermostat housing is the hot flow, and should be to the top pipe on the heater
If you don't want heat you shut the valve.
Ray
Ray Lee raybar2(at) tiscalidotcodotuk

Ray, by "from the thermostat housing" isn't that called the "bypass hose"? Mine goes to the bottom pipe with the left arrow "<--" and it does go to the input side of the heater. Are we saying the same thing or am I still confused?
Ed
efh Haskell

Ed,
As I recall with the Mohave heater it doesn't matter which is input or output. Anyone, please correct me if I miss-remember. Hot water just flows through the coils and the fan blows it into the cab.

The valve looks closed to me. Shuting it would stop flow to the heater.

Mort
Mort 50 TD

In regard to gene's comment about the "worst"place to tap off for a heater...this is debatable...and like just about everything other than the ten rules hauled down on the stone tablets.. There is no right and wrong way..just different ways to do the same thing. The "best" place to tap off is only 7degrees Celsius warmer the the "worst" place to tap off. The "best" place has a 3' longer hose run to the heater.. It is not unreasonable to expect more than a 7 degree Celsius temp drop in that run.

...just different ways to get the same thing done. The rear block tap is a much cleaner install and an easier install.
You have choices.. No worst or best, just different ways to get the same thing done.

Regards, tom
tm peterson

the by-pass hose outlet is the flow and should go to the top of the heater, the return is to the pump suction side (radiator return).As it is a pumped system it may not matter much which way it is piped.
On your system for the best results the flow should be tapped into the housing below the thermostat or
you can use the plate at the rear of the cyl head .
I have had my heater from the front of the head (TF housing is different) and the rear of the head and did not notice any difference in cabin temp.
Your present system will be subject to variance because of the stat if the old type is fitted.
Ray TF 2884
Ray Lee raybar2(at) tiscalidotcodotuk

Thanks guys for your comments. I think I've got it now. Just to avoid the confusion of future readers, my tap for the heater is in the front and I have no desire to change it.
Ed
efh Haskell

Looks like an elegant (simple) solution, Ed. How does your heater work on a cold day?
D mckellar

From the Y Register website. They have some good XPAG info, too. This is one method of installing a modern thermostat to replace the original bellows type. Same t-stat housing on the TC. Turns out the modern t-stat works out well when adding a heater.

Tom Lange has new housings made from an appropriate grade of SS to last a lifetime, where the actual thermostat is located more to center. Still works just fine for adding a heater. Very nice, so pricey. http://mgtrepair.net/Thermostat.html

Site here will not allow me to add a pic today, so here is the link to t-stat modify. Or google " mg y thermostat "

http://www.mgccyregister.co.uk/technical-information/the-xpag-files/cooling/xpag-overheating/

Above is 1st pic on page. Click on pic and it should blow up. Look at the 2nd pic, too, for a flow diagram
D mckellar

Heat works great! All done.
efh Haskell

Great! Just in time for the summer!
Gene Gillam

This thread was discussed between 17/04/2016 and 23/04/2016

MG TD TF 1500 index

This thread is from the archives. Join the live MG TD TF 1500 BBS now