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MG MGA - Original MGA Radiator Available for Loan/Testing

Could I suggest a possible experiment for the radiator/overheating club!?

This experiment could be carried out in both the UK and here in the US (and other areas as well)

I suggest that we have those with heating issues simply swap out their current radiator with a known original in working condition. I have an original radiator and am happy to send it to anyone here in the US who is having overheating issues. The owner could then simply swap out the radiator (six bolts and two hose clamps), and would have an almost immediate comparison in radiator function.

The variations in engine size, gearbox and modifications would not matter in this test.

An owner could take a car out for a run on a Saturday morning with his current (overheating radiator), record the temperatures obtained, and then quickly swap out the radiator, refill the coolant, and take the same run again - and record temperatures. The loaner radiator could then be sent back to the owner.

Any thoughts?

I will take my original in and have it cleaned out - not rodded out of course - and pressure tested up to 4 or 7 pounds. It will then be available for testing purposes. I am hopeful that this is a good radiator - it seems to flow well.

I think this is the only real means of determining if a particular car has a radiator issue.

I will watch this space!

Best regards

You're over-thinking this.

Just circulate coolant that's been heated to the same temperature through each with the same fan at the same ambient temperature. A sump pump and a 30 - 55 gallon drum will do nicely. A hose from your water heater drain will also work.

Measure input and output for temperature drop. You'll have your answer with a whole lot less work and zero variables.

Simpler yet, fill each, fan, and time the temp drop. First to cool wins.

Yes, that works as well - my main point is that owners in this situation need to replace the suspect radiator (on the same car/on the same day)with a known original). This removes the car variables (such as engine set up and gearbox) that are being reported in the thread "Radiator Survey"

For a test like this, I would prefer to simply replace the radiator in the actual car and go for a drive. Everyone wanting to test their system has a car in their garage - but not everyone would have a sump pump and a 55 gallon drum laying around. In the time it would take to assemble a test rig, I could have a radiator swapped out and be on my way.


I like your first suggestion MAndrus

You could make it even simpler by using your central heatings hot water tap, connected to the radiators bottom inlet by a rubber hose.
On my combi-boiler I can turn up my tap water to about 80 degrees C which would be about right for this test.
You would have to find out the pumping capacity in pints or litres per minute and you could easily use the hot water tap to adjust the flow to this.

Then simply measure the temperature difference between the radiator inlet(bottom) and the output (top)

Probably 30 mins work to set up which would be much quicker than switching radiators. (I find that fitting the hoses is a bit of a fight on my car).

Once you had this set up it would be really easy to switch rads and compare their performance.

I may have a go at this over the winter and test my two radiators.

c firth

I forgot to add that I would use a spare electric cooling fan that I have to provide the airflow through the radiator.

c firth

An interesting test.

It could be performed with downflow/crossflow comparisons. Aluminum/brass, old vs new. etc.

Removing the car, engine RPM's variations, driver, traffic, wind, acceleration etc., from the test is critical to getting repeatable meaningful results.

Also, a high performance thermometer hooked up to a computer to properly graph time/heat loss would be important.

I'd love to see an article.


thanks for the link,
we really do need a "flyinmiata" style test for all our MGA rads, I wonder if the would let us use it?

c firth

I always when I have my radiator out for cleaning I have it rodded out by the shop removing the tanks to make sure there is no build up of any material which would slow down the flow of water. Why is it you do not have it rodded out. Is there a problem with having that done?

Jeff Becker

Hi Jeff - the radiator is an original "cell core" or "V cell" radiator and this type of construction can not be cleaned out by having it rodded. The passageways are not actual tubes. I will attach a photo from the MGA Gura site.


That is the same type of core I have
dominic clancy

Would it be safe to use some kind of de-scaler in the radiator to help clean out the tubes?

Or does this stuff dissolve the soldering at the same time?

c firth

I would think that fitting a known "cool" rad would identify if the old radiator was the cause of heating very simply (and clearly)

dominic clancy


"IF" my new radiator wasn't waiting on me in the shop right now and "IF" it wasn't so bloody cold right now I'd jump on this offer.

Interesting that you said that the v-cell radiators couldn't be rodded out - I remember quite distinctly that I PAID to have mine rodded out back in whether it was actually done or not I have no idea. I don't see why the tubes couldn't be rodded out though...they're simply those skinny slots between the fins, aren't they? Surely a radiator shop would have a tool that would pass down through them.

Gene Gillam

Just returned from picking up my radiator from the shop...I didn't get a v-cell replacement core so it looks almost exactly the same as it did when I dropped it off but it weighs at least 5 lbs more than it did then. John, at the shop, was impressed with the core and says it has more tubes and fins and is better made than the core that was replaced. He said that the core he removed had the outer tubes on each side soldered closed - he said this is typically done because the outer tubes are the ones that leak first so the core manufacturers close them off. The outer tubes in the new core are open and will hold water.

I also asked him if it were possible to "rod" a v-cell core and he said "Sure". He said v-cells were typical until the early 70's when they went more to the current design. He pulled an old core down and showed me how they rodded it - here's a photo of that:

Gene Gillam

Hi Gene - I say that they can't be rodded out, but that may not be true. I am basing that on what Barney's site mentioned.

Those passages do seem awfully narrow and they do follow an accordion-like path, so I am thinking it would not be a great idea to try and have them rodded.

I will ask the folks at a good shop we have here in Atlanta.

Edit: that is a helpful photo Gene - good to see and great to know! Thank you.

I am hoping I do not have to have the tanks removed from mine - so I am going to try the chemical dip first and see what happens.


Continuing on from the thought above, prior to the last couple of weeks when someone mentioned radiator tubes and "rodding" I had always thought of round tubes and round rods. That's not the way it is...tubes are really flattened cylinders to provide maximum contact to air flow and "rods" are flat pieces of metal that are pushed into these flattened cylinders to clean them out.

Here's another core with several different rods - the one in the core right now is too small, merely there for demonstration purposes.

Gene Gillam

Here is a good drawing to explain the construction of the cell core (bottom) compared with the modern 'tube and fin' construction (top). It shows why they can't be rodded because the 'tubes' or passages for water flow zig zag from the top of the core to the bottom.

This may also explain why the cell core construction is better at transferring heat from the water to the air because there is significant water turbulence due to the many changes of direction compared with a straight tube...................Mike

m.j. moore

Okay...can't believe I didn't see what I saw with my own eyes at the radiator shop so I searched the internet and found this on the JagLover's Forum:

> Date: Wed, 26 Nov 1997 10:32:57 -0500 (EST)
> From: JamieDFiff at
> Subject: Re: [xk] Overheating Radiator V-Cell
> Note that the original type XK radiator is a "V-Cell" that does not have the
> typical tubes that can be "rodded" out. Once a V-cell becomes corroded
> inside no flushing will help. I would suggest that a new radiator core will
> solve you overheating problems.
> Jamie
V-cell radiators can indeed be cleaned out by removing the top tank
and carefully rodding them out ,I owned/worked in a radiator shop for
25+ years and recently successfully cleaned the radiator on my 150
,maybe you are getting confused with honeycomb cores used in veteran
cars . The v-cell may not be as efficient as the later type but I have
found that the brand fitted to Jaguar cars to be of very durable
construction , I am comparing them with the radiators of the same
construction that were used in Holdens up to 1965 which was about the
time that Jaguar changed to a tube type core in the Mk2.One of the
limiting factors was the v cores inability to withstand any more than
about 7 psi .

Regards Don
1958 Xk150
Gene Gillam

Hi Gene - I say that they can't be rodded out, but that may not be true. I am basing that on what Barney's site mentioned.

Those passages do seem awfully narrow and they do follow an accordion-like path, so I am thinking it would not be a great idea to try and have them rodded.

I will ask the folks at a good shop we have here in Atlanta.


Just adding to the above - great pictures and illustrations from both Gene and Mike! I now know much more than I did this morning!

It looks as if they can be "rodded out" - but a round rod is definately not used in the process! I would also hope great care is used when this is done.

The illustration Mike provided and the pictures from Gene should be added to the MGA Guru site - maybe Barney would be interested in some of the text provided by Gene.

Thanks so much gentlemen

This is a front picture of my cool running (175) radiator, supplied by Bob West about 15 years ago after my original sprung a leak.


Steve Gyles

From the excellent diagrams and photos I gather that the zig-zag part is only a heat dispersal (radiating) fin - and does not carry water. The "cells" do seem to run top to bottom like the tubes but with S shaped flow . When I got my car in 2003 , I cleaned out one of my rads using kettle descaler - put a plug in the bottom outlet and filled it with boiling water with the descaler added and left it overnight.Not tried the spare rad yet - I've only had it 10 years after buying it on ebay for 30.
Modern rads look easier ( and cheaper) to construct .
Cam Cunningham

I had my original 1961 factory fitted radiator 'rodded' on a number of occasions and eventually gave up and replaced it with a new MGB type. No difference in overheating at all!

Yesterday 32C, took it for a 15km. run and it gradually got up to 212 and boiled over in the garage when I got home.

It is booked to have the electronic dizzy and tune checked later this week so will leave any further adventures until after.

Photo of original shows the over-flow stain and the 'gobbs' of solder to try and contain the water!

I will post another photo of the 'new' one showing the different cell structure.

Barry Gannon

Missed the photo!

Barry Gannon

Now the site won't let me upload the photo of the new radiator. I will try again later. Barry
Barry Gannon

Here is the photo of the 'new' one.


Barry Gannon


Did you give up on your old V-cell (from the picture) radiator because of overheating or because of the leak?

If the latter then it would be interesting to change back from your new 'tube & fin' radiator to see if there is an improvement while the weather is still warm.

For the test you could always run without pressure if the leak is significant................Mike

m.j. moore

Mike, I have used that V-cell for more than 40 years and 4 different motors! Lots-a-miles! It always kept the temperature at reasonable levels (struggled at +40C) but it has been disassembled so many times that it now seems impossible to re-seal - hence the build up of solder.

Last 4 years it has not been good and I'm told it is beyond repair - so the change.

I'm waiting first for the tune-up, and then will make a decision after considering your collective comments from this forum.

Thanks for your ideas. Barry.
Barry Gannon


I hope it was not my driving your car on the race circuit that accelerated the radiator's demise!

Steve Gyles

Hi Steve, No, it was cool that day so no problems even at 'the ton'! The long drive to and from Philip Island gave no trouble either - cooler weather again. I will report soon on the outcome of a tune-up. Barry
Barry Gannon

This thread was discussed between 03/12/2015 and 09/12/2015

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