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MG MGA - overheating solved

It's been a while since I posted on this board and a lot of tread has been laid on the asphalt since I last did.
I always read with interest all of the overheating posts and yes, I know, overheating is a relative term but there is no reason why an MG should run at temperatures above the thermostat rating under normal usage. I'm talking about normal usage not under a load climbing the Rockies or stuck in traffic for extended periods of time. Here is my story: My 1959 MGA 1600 began to run hot and I could not figure out the problem. Being exasperated, I bought a reproduction radiator from Moss.(I live 2 miles from their Goleta warehouse.)This was in 2006 and the fit and function of the repro was excellent. I had no complaints until 2014 when I began to run at temperatures that were hotter than normal. 180* thermostat and running at 212* plus some other serious problems with the engine lead me to a total rebuild. I chalked up the higher temps to some internal problem with the engine and did not think the radiator was the problem. With the new engine installed and the carbs rebuilt and a hundred other things done to the car I drove it about six miles and the higher than normal 212* temperature was back. I did a radiator flush, opened the slats of my grill, double checked the timing, added water wetter without a significant improvement. I will say that after all that the temp would be 190* around town and 205* at freeway speeds between 60 and 70 MPH. I can hear you guys already saying there's nothing wrong with those running temps but I was not satisfied.
I took the original radiator to the best radiator shop i town to have it repaired. It had a small pin hole leak near the top tank which is why I sidelined it in 2009. Look at what he found when he pulled the top tank off of the core. See pics. My community has some of the worst water on the planet in terms of dissolved mineral content and I have always run tap water and antifreeze at about 50/50. Our local tap water caused a nearly complete shutdown of the channels to pass water. This was why I was overheating. The original was cleaned and rodded and now I am running at a happy 180* climbing to 185* on the freeway for extended periods of time. Lesson here is to run distilled water and antifreeze only. No more tap water for me. As for the reproduction radiator the theory is that either it plugged up as my original did over the course of 9 years or so because of my local water or there is a metallurgical reaction with the silver content in the solder and the coolant which causes a "bloom" to occur that cannot be flushed out with the various chemicals available. This is my story and I solved the problem with the MGA running hotter than it should.


David Holmes

*sidelined in 2006 that should be. Here is another shot closer of the left side of the core.


David Holmes

David, Thanks for that comprehensive coverage of your success. Very enlightening. I have a new radiator fitted and not a scrap of difference to running temperatures!

Still working on it (after the Christmas break) I just don't take it out in hot weather.

Barry.
Barry Gannon

David. That's horrible! What a pic! Glad you have found the problem but, just for completeness and my difficulty in analysing the picture, where are the actual waterways supposed to be in the picture!? Looks like there is nowhere at all for water to flow and surprising you didn't boil within minutes. Do you have the same pic after rodding to show the before and after, or of another similar radiator in good condition?
Bruce.
Bruce Mayo

David

Genuine question here about distilled water. I noted in the other thread that Dominic said: "Pure water / distilled water in cooling systems also cause corrosion, which degrades cooling system performance. For these two reasons we add coolant additives / antifreeze (according to climate - antifreeze also has corrosion inhibitors) which have a small effect on specific heat capacities."

I had a look on the web and a host of people say to use distilled water. I can understand the potential need in very hard water areas, but does anti-freeze negate all those issues? It's not as if new water is constantly running through the system, it is a sealed system with a one off input of just 4 pints of the water, assuming a 50/50 mix with antifreeze. I am in a very hard water area but have a water softener system. I used that water with antifreeze in the car and as far as I can see I have had no build-up in 15 years.


Steve
Steve Gyles

I agree with Steve that even if you live in a hard water area and you have a sealed system it wouldn't make much difference filling the cooling system with tap or distilled water. Using very hard tap water for the entire cooling system would be adding less than half a teaspoon of solid matter (mainly CaCO3) to be deposited over all the internal area of the engine and radiator which would be no big deal.
However, Dave's radiator will probably be over 50 years old and I guess for most of that time has not had a sealed system and we all know how often a half pint or so of water gets dumped from the radiator after a run. Regularly topping up with hard water will eventually clog the tubes and reduce flow rate.
So I would say it's a good idea to use distilled water (+ antifreeze of course) for topping up if you don't have a radiator overflow system.
Also, rather than going to the expense of taking your old radiator to a shop to have it rodded (I still can't see how a cellular core radiator can be rodded!) it might be a good idea to give it a descaling treatment as you would do for your kettle. Fill it with acetic acid (vinegar) and leave overnight..................Mike
m.j. moore

I wish I had a picture of the rad after cleaning and rodding. The photo does show the channels barely. There are two of them one above the other I believe all the way across the core. I do not know how many there are. As to whether this debris was from the block... I don't know but it is likely that some of this may have come from the block. This radiator operated flawlessly for years from 1986 to 2005 before I started having problems. I had thrown a fan blade that destroyed the original core and was replaced in 1986. The engine was rebuilt in 1988.
David Holmes

We too live in a very hard water area, in fact the water is so hard, it will literally eat a standard immersion heater in a matter of months! We have a water softener, but better than that, because we live in a 1920s house with solid walls, we have de-humidifier. This device provides us with a constant supply of distilled water, which is the only water I use in in cooling systems. It is amazing how clean everything in the system keeps when this is used. The distilled water is also good for topping-up batteries.
Lindsay Sampford

This thread was discussed between 21/12/2015 and 24/12/2015

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