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MG TD TF 1500 - Cooling system chores

Later this summer I'm thinking it's time to go through the cooling system. here in Tucson we get plenty warm so I want to be sure the system is running efficiently. I'm thinking of
having the radiator flushed, rebuilding the water pump and installing a six vane impeller, maybe putting in one of Toms' water thermostat housings plus new thermostat, and maybe upgrading to an MGB fan. Anything else that I should be doing while I'm doing all this? I also plan on replacing the heater hoses with steel pipe running under the manifold.
Suggestions ?
Geoffrey M Baker

Butch Taras can take care of your water pump for you. He did mine. Bud
Bud Krueger

Another concern should be whether, in the time the car sat, the cooling system sludged and rusted. Flushing the block helps considerably. I have found the original foundry core support wires still in place in the cooling passages of the engine, obstructing flow.

You also should look carefully at the core plugs - steel ones rust and leak without warning.

Tom Lange
MGT Repair
t lange

What's the easiest way to flush the block?
Geoffrey M Baker

When I first bought my TD, I had overheat problems. I took the radiator to a shop and had them "Rod Out" the tubes in the core. I believe it required removal of either the top or bottom tank from the core, then boil it out in their caustic tank. That helped but many years later, I had the original three row core replaced with a four row core. St. Louis summers with high temps and humidity don't bother my engine any more.
Jim Merz

Come to think of it, maybe the original was a two row and I now have a three row core. Old age (mine)!
Jim Merz

Geoff, when the engine was out of the car I got stuck into it with a Guerni high pressure hose after knocking out all the welch plugs. It was amazing to see the amount of crud that came out. Use brass welch plugs & a sealant (I used Stag) & seat them with a firm tap from the ball on the head of a ball pein hammer. I plan to fit a pantyhose filter @ the top hose to stop any residual crap from entering the newly reconditioned radiator, for a few hundred miles @ least, checking & cleaning as required. I modified the (original) thermostat housing to take a Repco Holden thermostat ($16) & blanked off the bypass pipe with a small hole in the blanking plate to prevent airlocks. Cheers
Peter TD 5801
P Hehir

Geoffrey,
Might want to consider having the exhaust manifold Jet-Hot treated. Or any other treatment that includes doing the "inside" allowing hot exhaust to escape quicker. Lots of info in the archives on this.
I noticed about a 20 degree drop in operating temp after doing mine.
David Sheward 55 TF1500 # 7427

I'm not planning on taking the engine out of the car if I can avoid it.... How to flush it in place ?
Geoffrey M Baker

Geoffrey,
drain the system,, replace with a mixture of 1 cup Arm & Hammer Super Washing Soda and water,,, run it fo 40-50 miles,, Fit a Prestone radiator flush kit discharge piece to the rad inlet,, back flush it with a garden hose connected to some reducers to fit a neoprene hose connected to the block drain spigot,, This works quite well,,,,

SPW
SPW Wincze

I managed to get the block drain open (after half an hour of running bits of wire into the block drain valve, it finally started to flow) and the radiator drain. Running a garden hose through the block now, it was surprisingly clean in only a couple of minutes.
So far so good! I'm in contact with Butch Taras, so the next step is to make a decision about the water pump.
Geoffrey M Baker

Geoffrey,
Not sure how deep you want to go.
For many reasons I had a lot of overheating problems. I tried everything you mentioned. The results were always minimum at best.
Nothing compares with a core replacement. I put a four core in to replace the original 2 core. Same top and bottom tanks and just a very minor adjustment. Can never say enough good things about that change. Tremendous difference.
And of course a proper tune up will keep the engine running cooler.
Mort
Mort 50 TD

Mort, I want to go as deep as she needs, no more. As in so many things, I just need to get involved up to the point that I finally understand the system and have some sense of potential problems. So far, I have flushed the block and radiator, and inspected the thermostat. While pretty dirty and crusted, she cleaned up nicely and seems to work just fine - the old "pop her in a pan of boiling water" trick worked fine. I stripped one screw holding the bypass hose junction, and have to replace all the gaskets of course; but otherwise everything seems good. To my surprise I was able to get the engine block drain working! And everything was running clear in just a couple of minutes of pressurizing.
So now I'm reassured - the cooling system doesn't seem too bad. I'm thinking I'll just reassemble her and get her back and running; and over the course of the summer I'll see how she handles the heat. And then I'll replace things one part at a time to solve any problems that come up. But this way, there should be no real surprises!
By the end of the summer, I hope at least to have a 6 vane pump in place if nothing else, but hopefully I'll have managed to replace the thermostat with a modern unit, upgrade to an MGB fan, and jet-coat the inside of the exhaust manifold as well. And if she still runs hot - well your solution seems like the last essential step!
So tell me, who sells a 4 core radiator that will fit a 1951 MGTD?
Geoffrey M Baker

Hi Geoffrey,

I don't want to discount the positive aspects of your flushing the block - but I can almost guarantee that a great deal of sediment remains in your water passages. The deposits become almost as firm and set as the cast iron - when you remove the core plugs, you are able to chip away and poke through the sediment build up - it is really surprising what accumulates within the passages over the years.

I mention this only to emphasize that the clear water from your flush is only indicating that the recent build up has been removed - I think you most likely still have a good bit of sediment in the block. I was able to poke through much of it with coat hanger wire - and could not believe when it would I would poke through what seemed to be actual casting (only to reveal a layer of sediment).

Good luck with your project - hope you have a cool summer,

DLD

Thanks, DLD; some day I'll get the engine out and that will be the time to go through the passages!
Geoffrey M Baker

Geoffrey,
I don't believe there is an off the shelf replacement for the entire radiator. I brought mine to a real old time radiator shop in a neighboring town. These two old timers(brothers) just got out their measuring tapes and called their supplier with the dimensions. They used my top and bottom tank and soldered it all up. They cleaned and painted everything.
The 3 core would have fit with no modifications. I went for the 4 core. There is a small 90 degree flange on the front that they just straightened out and the core extends maybe a 1/4" forward of the original. The dimension from the back of the core to the fan is the same.
You can not tell it from an original.
I love it.
Good luck.
Mort
Mort 50 TD

I went through this over a long period with my TF. Tried flushing (x3), taking stat out, new pipes, fitting MGB fan, new pump etc. In the end the only thing that worked was recoring the rad. I took the rad out and took it to a local shop and they made up a new core. It now sits on 85 degs whatever the weather and doesn't move.

AJ
A R Jones

This thread was discussed between 01/06/2014 and 04/06/2014

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