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MG TD TF 1500 - Adding coolant reservoir for TD

I'm unable to locate previous discussions relating to adding a coolant reservoir off the overflow pipe from the TD radiator.
R C Flowers

See http://www.ttalk.info/Tech/Overflow_tank.htm There are a number of threads in the archives. Search for 'overflow recovery' Bud
Bud Krueger

R C
I have a recovery tank that I believe came from a B if you want it.
I no longer need it since I have resolved the issue that precipitated my installing it.
I believe I had a post on it a few years ago.
Let me know via e-mail if interested. mortres at pobox dot com
Mort

Mort 50 TD

RC, here is a picture of my MGB overflow tank mounted on the battery hold back bar on my TD. It is up and out of the way and easy to occasionally check the coolant level. I use a 3 lb. cap which has made no problems with my radiator tank. The two piece holding strap is home-made from some thin stainless steel. I made a support for the back of the tank that is curved to fit the rear shape of the tank and lined it with some felt between the tank and the wood bracket. It is all very stable and has lasted for years.

Jim Merz

this does not answer your post, but i am curious as to why you would install one. regards, tom
tm peterson

Ditto on Toms question,,, once the rad finds it's level, it should stay there. A tank doesn't help in cooling the engine.
SPW
Steve Wincze

I don't have a problem with overheating and I know an overflow reservoir doesn't help cool the engine.

I experienced my problem when I slightly overfilled my radiator and it belched it out via the overflow tube. Some of the coolant/water blew back onto the engine and I didn't enjoy the resulting smell. Since finding it's level I don't have a problem.

Bottom line solution is "don't overfill the radiator". My thinking was it would be prudent to have a catch for the overflow just in case it was overfilled in the future.
R C Flowers

I run a 190 degree thermostat, to make my heater more effective, and if I turn off the engine while the thermostat is closed is closed I sometimes hear a gurgle in the cooling system and lose some coolant.
Withour a recovery tank the coolant is lost, but with a tank some or all of it gets sucked back in as the engine cools off. I believe it is the residual heat in the head and block chambers which goes from 190 to 212 and creates a steam bubble which pushs out the coolant.
If I had it to do over, I'd put in a 160 degree themostat. I may still have a problem on a hot day
if I turned off the engine after a hard run without letting it cool down first.
JMHO
Chuck
cj schmit

Mort, thank you very much for your offer. I have one slightly smaller than the B model that would work and I'm pretty good with fabrication.

I remembered reading about the overflow reservoirs on this site a year or so ago, hence my question regarding the input since so many people are willing to share.

Thank you all.

R C Flowers

Read the story in http://www.ttalk.info/Tech/Overflow_tank.htm Bud
Bud Krueger

I have installed a pressure cap to the TD, run the overflow hose to a pressure cap neck, soldered off at the bottom, with a nipple for the overflow hose. You now have a pressurized system 4-7# max.
You will now have a more modern system, like a TF, & every other car, built since ...
This also eliminates any steam pockets @ the exhaust valve area of the cooling system.
Len Fanelli

Len, I have an ON/OFF 4# cap on mine. My new pump from Butch works fine at holding 4 psi. Bud
Bud Krueger

Len, can you share a photo depicting your modifications? Thank you.
R C Flowers

I used one from NAPA. Tube type most rodders use.

MG LaVerne

Seems to do the trick.

MG LaVerne

MG LaVerne,

Thank you. Are you connecting to the reservoir from the bottom of the radiator overflow pipe or at the side of the radiator neck just under the cap?
R C Flowers

Ran a rubber hose (with a hose clamp) off the bottom of the overflow tube to the bottom of the new tank. When the water expands it goes into the tank. Put some coolant it the overflow tank to start with. when it cools it pulls the coolant back into the radiator. You need to have a good seal on the radiator cap for it to work.
MG LaVerne

Thank you MG Laverne. That's the direction I'm going to go. Now your system is pressurized. What # cap did you use?
R C Flowers

I'm a bit confused our cooling systems are an open non pressurized system, correct ? I understand that heated water expanding can be directed into an "overflow" container. But how does an open system allow for a return process during cooling in an open to the atmosphere situation, other than by gravity which would not seem possible unless the overflow container was attached to the windshield wiper motor.
Jon Levine

Jon,
When you put a hose on the overflow pipe from the rad and direct it to the bottom of an expansion tank. You will also need a good seal on the radiator cap - It will draw excess coolant back into the rad as it cools (and shrinks) by the created suction. The expansion tank is open to atmosphere so allows the excess coolant pushed out of the rad to return. The system is still open to atmosphere but coolant will not be lost on the ground or over your engine.
If you have a problem with the cooling system and it boils - then possibly you will lose excess coolant through the overflow pipe of the expansion tank. That is another issue you would have to solve and has nothing to do with the expansion tank function.
Filling the Rad to the top and having some coolant in the expansion tank per Lavern’s suggestion to begin with - should keep the Radiator and pipes full at all times.
The overflow pipe from the expansion tank can be directed down below the car and away from the engine.

The rad cap on my TD has a good rubber seal anyway which forces excess coolant out the overflow pipe curently.

Rod.
R. D. Jones

MG LaVerne,
Does it matter if the tank is fitted low down like yours or up higher near the battery like Buds.
Robert
R Browne

If you have a good seal on the cap, either location works. Without a good seal, neither location works. Regards, tom
tm peterson

Thanks Tom.
Robert
R Browne

Got it. Thank you all for your input.
R C Flowers

I tried to take a photo, but it is mounted too low for a clear picture.
I went to a radiator shop, & bought a top tank radiator neck, & pressure cap, then soldered the bottom closed, drilled a hole in the capped bottom for a nipple, for the TD overflow hose, I used a air drill motor side handle to attach it to the bearer plate.
Not a reservoir, but now a pressurized system.
Len Fanelli

Mg laverne
From what I had read before the tank top needs to be the same level as the radiator tank to keep from a siphon effect or "water seeks its own level" . Do you have an issue with your tank being so low?
TLW Wright

I have no issue with my tank.It works just as intended.
MG LaVerne

We seem to be getting a bit carried away in the analysis of the physics of this simple system. Mine works just fine with an unsealed cap. The coolant that goes into it is forced there, through the overflow pipe and tubing, by the water pump. When the engine cools down there is a vacuum created in the sealed radiator due to the cooling off of the system. The coolant in the expansion tank is then sucked back in. A sealed cap on the expansion tank just means that the system has to work a bit harder to push the overflow into the tank. Bud
Bud Krueger

MG Laverne
So your tank is not vented i take it.
do you fill your radiator as normal or do you flood to get more of the air out?
TLW Wright

Bud I think you are confusing "sealed" with "pressurized". The cap will need to make a good seal on my non pressurized tank in order for vacumn to pull the water back to the radiator from my over flow tank. While a tank with a higher mounted over flow will work to contain the expanding water, it will not require a good seal on the cap to do so, but it will require careful placement if the seal isn't there or you may find the coolant escaping out of the top of the radiator cap.

A pressurized system would have the advantage of raising the boiling point on the coolant. Which mine is not.

TL, My radiator is a non pressurized stock unit. It vents as any stock one would. When the coolant expands it flows out of the overflow tube. The difference is that it does not drop on the ground but is captured in the expansion tank shown through a connection on the bottom of that tank. The expansion tank also has an overflow tube of it's own. Should the level in that tank get too high it will flow into that tube onto the ground. What this setup will do is keep the coolant level at the optimum level in the radiator ( right to the top of the overflow tube). Without any over flow tank ( either high or low) the expanding coolant will flow out the tube onto the ground. When the coolant cools and contracts the level will drop considerably in your radiator. Nothing really wrong with that as that was how the system was designed to operate. However it means that you should check the level more often than you would a modern vehicle. My tank will not eliminate that requirement but does reduce that requirement a good deal. In addition in todays world seeing antifreeze spill on the earth on a regular basis is frowned upon.
MG LaVerne

LaVerne,
I have the same set-up and it works fine.
Regards
Declan

D Burns

ok. i got it then. the system is not flooded so what goes in this tank stays there and is really what just runs out the tube now. basically a catch can. as the level goes back below the overflow tube in the radiator it stops putting it in the can. Duuhhh, Sorry was thinking a flooded system. takes a little while sometimes...
TLW Wright

Not entirely TLW. When the temperature lowers in the radiator it will create a vacumn and draw the coolant from the catch tank back into the radiator.
MG LaVerne

Well I am going to give it a try. Ordered one today. Tired of the mess. Thanks for the idea and info.
TLW Wright

This thread was discussed between 28/07/2014 and 14/08/2014

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