Welcome to our resource for MG Car Information.



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 - MG TD cooling system - thermostat

Hi, I have just joined this board having purchased my first MG TD some two weeks ago. I have very little information on the car, but it seems to have been restored some 15 to 20 years ago. One of my first tasks was to replace the rubber hoses in the cooling system, as these looked in poor condition and likely to fail at any moment. On removing the existing top hose I found that the top metal housing to which it connects was empty, whereas I was expecting to find a thermostat. Is this correct, is the cooling system meant to have a thermostat? I would imagine that without such a device the engine could take a long time to warm up and may not even reach optimum operating temperature during cold weather.

M J Davis


Welcome to the board. Yes, you are correct that the engine needs a thermostat. The original thermostat was a heavy affair built into the housing that attaches to the head and included a blanking sleeve for the bypass tube. Although they are no longer manufactured, they appear on ebay from time to time.

It is common today to remove the mechanism and add a small relief to the top face so a modern thermostat may be put in its place. Make sure you use the type of thermostat with a small bypass hole. But you aren't done yet, you also need to create a blanking flange with a 3/16 inch hole for placement in the elbow fitting. Two gaskets will seal the blanking flange.

There is a lot of infromation in the archives. You may want to look there for some of your answers. You can go on my website and peruse the MG TD 15470 section for pictures...

Dave Braun

Welcome to the BBS, Matt.

Dave's quite right - there's a wealth of info in the archives, on just about everything you will want to know, and pointers to other published information on the web. Without I hope singing Dave's praises too much, his website is excellent for detailed shots of his car restoration and I'd suggest you spend some time looking through that to get you more familiar with all aspects of your TD. Other contributors to this Board have published and you'll come across these as you browse the archives looking for more detailed information.

For spare parts, there's quite a bit of new and second hand gear for the TD on e-Bay, some of it better than others - with often more second-hand parts in the US than the UK (vast numbers of TDs were exported to the US). The MG Owners Club (sadly) doesn't stock TD spares but there are several established general UK suppliers - Brown and Gammons, Moss and NTG Motor Services of Ipswich are the largest I know of but there may be others and there are also suppliers of specialist parts (electrical, etc.) They're also on the web and, one way or another, you should be able to source about everything you need.

First off, if you haven't already got one I'd suggest you buy a full workshop service manual. It is still in print, is very detailed and completely invaluable. You might pick one up on e-Bay but Amazon stock them as: "MG midget TD & TF Workshop Manual"

But I would warn you, the whole ownership thing gets time-consuming and addictive: I bought my 1953 TD just over a year ago. It was a good runner and in reasonable shape, following a full restoration in the late 70s but with dry storage and very little use since. I started off intending to do "just a bit here and there", mainly changing non-standard bits as I went along but one thing leads to another and I'm still busy .........

Have fun (as I'm certain you will).


- Tom.
Tom Bennett - 53TD 24232

Thank you Dave and Tom,

I have already found your website a wealth of information Dave, but as always there is never a photo of the particular little detail you are after! I have just found this little collection of pictures which shows what a TD thermostat should look like: it seems that mine has had its guts removed, just leaving the housing. I could buy a replacement from Moss, but they are about 60. I'll keep a look our on ebay.

Thanks for the tips Tom. I've got the workshop manual and as you say its invaluable. Like your car mine has been "restored" at some time in the past and I think has many non-standard features. In addition to the thermostat problem I found at the weekend that a previous owner had bodged the radiator drain by solding in a large nut and bolt to form a removable drain (presumably the original had corroded or was broken. I tried undoing the bolt and the whole lot sheared off at the solder because the bolt had rusted solid, which resulted in a rapid draining of the radiator and means I have to repair this before anything else! Fortunately I have a friend who can form a new threaded drain hole set in a brass plate for me to solder over the hole. I will then install the proper brass drain tap and hopefully that should be a better long-term repair.

M J Davis

Matt - In addition to e-bay, there is a classified section on this web site, where a goodly number of used items are offered, including T series parts - check it out. Cheers - Dave D.
David DuBois


If it helps to know, I am also based in Surrey (nr Godalming) have been owned by a TDII since 1964, and done almost all the jobs on it at some time, not always right the first time! The TD is currently in Cumbria but it gets visited regularly. But I have a TF1500 here, and many of the solutions are the same. If I can be of help, please drop me a line.

As for the thermostat, I have found it is worth the effort to replace the whole unit, since I could never get the insert to stay in the right place. And whilst the radiator is 'hors de combat' it is worth doing a reverse flush, they can get pretty cruddy over time and it is always one of the jobs to do tomorrow until the whole thing styarts to overheat seriously.

The other invaluable book is Blower's MG Workshop Manual.

Ian Bowers

I pulled the original thermostat off the car and put it in a pan of water....just before boil, it opened nicely.... must be working as it never overheats and just hums along.....
gblawson(gordon- TD27667)

Hello Matt

I think I may have a thermostat to suit but the brass cylinder inside the housing has broken away from the 3 "spokes" holding one end. I believe it may have come off one of my YBs (First one crashed and cannibalised in the early 70s, second one now sold after storing it for the last 35 years or so).

Consequently I am gradually auctioning everything off on E-Bay so that everything finds it's own price. This includes an XPAG engine and a gearbox currently listed. If you don't have any joy getting a good one please let me know and I will list it on E-Bay as a priority.

Best wishes

Clive Evrall (
J.C. Evrall

Hi all,

On a lighter note I first had a TD in the 70s and in daily use summer and winter - that's how it was then! I ran it for years without a functioning original thermostat - never a problem - ignorance was bliss!

Ian, just a small point, Blowers is very expensive new,and not much less second hand. There's no doubting it's use for pre-war models but it mainly just repeats WSM content post- war. I've never seen a need for it anyway.


J C Mitchell

If you smear a bit of White Lithium Grease on the inside of the hoses, where they attach to the castings or radiator, it will be a lot easier to remove them in the future!!

Steve Wincze

matt, i don't have the document in front of me now, but the articles i have read state petroleum based lubricants will deteriorate natural rubber based products. a quick google search had that same info. i use silicon grease. regards, tom
tom peterson

It is too bad that we cannot determine where the bellows of our thermostats are manufactured. I assume that the thermostat failures are due to a malfunctioning bellows. What a find that would be!!!
Jim Merz

Hi Matt,
Like Ian I'm also based in Surrey, Chessington. I've had my TD since 1968 so if I can be of any help please get in touch and if you want to pop over just to 'look at something' then I'm around most days.
But for technical advice and support, this BB is the simply the best.

Mike Christie

This thread was discussed between 09/08/2010 and 24/08/2010

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.