Re-cored radiator and still loosing colant
 

Good morning all,
The old radiator core had 62 tubes in two rows, and the new core has 81 tubes in three rows. The car runs so much cooler than it did - vey happy about that.
After about two and a half hours if driving the coolant level is about 1/4 inch over the top of the tubes. So throwing coolant out the overflow is still happening.
I've read that some owners have ground down the impeller blades to slow the flow assuming it pumps coolant faster than it can flow through he radiator. Hard to believe but I am stumped.
I'd appreciate comments on you experiences. Thanks.
Al Leach

Re: Re-cored radiator and still loosing colant
 

If you topped off the radiator/overfill, it will spit out water. Make sure overflow tube is open.
I have a old gasket on a flip up quail cap and that will spit if the level is not right.
Don't mess with the pump yet.

Re: Re-cored radiator and still loosing colant
 

I'd install a thermostat and see how it does.

Re: Re-cored radiator and still loosing colant
 

Make sure you have a baffle in the top of the radiator, if you have one you won't be able to see the top of the tubes. Usually the water to the bottom of the baffle is adequate.

Re: Re-cored radiator and still loosing colant
 

Thought I read in other threads that this is normal as long as it does not go below the tubes?


In some cases it may go below the tubes, the key is to keep an eye on it. See if it stabilizes reasonably and does not keep continue losing coolant. The radiator seeks its own level, and then stabilizes.


If with continued driving it stays at that level all is good, you are probably overfilling. The other info in the other points made are good too.


If still losing coolant, baffle is installed, check to see the height of the overflow tube in the radiator next, should be only slightly below the top of the radiator fill opening.


I've seen posted there is an old trick, roofing nail put in the overflow tube.

Re: Re-cored radiator and still loosing colant
 

The water level just above the core is where it's supposed to be. It finally reached its level of happiness, so don't add more coolant or else that will get spit out, too.
Also, put a roofing nail with a wide head inside the overflow tube up top. That will drastically reduce the amount of coolant exiting at the bottom of the tube.
If you are running a split radiator cap - like 99% of modern owners do - use a thicker O-ring or cardboard/fiber ring between the two halves to the point that you have to exert a great deal of downward pressure as you twist the two halves together. The Flying Quail and Moto-O-Meter reproduction caps may look great, but they are designed leakers between their halves. I finally gave up on that repo crap and now use a factory style flat cap when doing highway or sustained long distance drives because coolant doesn't blow out. Around town I put the flying quail back on. Until I can buy an original FC radiator cap that functions properly, I have resigned myself to do this so that I can keep my sanity - and temper.
Marshall

Re: Re-cored radiator and still loosing colant
 

The last two postings were typed and posted at about the same time; hence the duplication of advice.
M.

Re: Re-cored radiator and still loosing colant
 

Gentleman,
Thank you all.
Your confirmation on the "happy" level is just what I needed.
I didn't realize that level was quite so low but that's fine with me because it does run nice and cool.
The overflow tube is about 1/8" below the bottom of the Moto-meter and the meter doesn't leak at the split.
I'm also adding that roofing nail to the overflow tube as soon as I come up with one.
Thankyou again,
Al

Re: Re-cored radiator and still loosing colant
 

Sent Private message, questions about his re-core.

Re: Re-cored radiator and still loosing colant
 

I think you will find that the new cores have smaller tubes than the original cores. This makes them cool better, but they flow less fluid. the pump was designed for the original radiators, and they can flow the GPM of the pump, but the new cores cannot, so excess fluid is expelled by the overflow tube. Adding a thermostat to slow the flow of the pump will usually solve that problem.

Re: Re-cored radiator and still loosing colant
 

Think this myth through, the pump can only return water to the top of the radiator that has already came through said radiator. Impossible for water to pile up in the top tank. Think of the water pump as a vacuum pump rather than a pressure pump. It can only eject what it can pull in. It is not a pressurized system, but it IS a closed loop. The turbulence created by lots of flow cools better than slowly circulating water. However, reducing the output of the pump does reduce the negative pressure in the engine block. Higher negative pressure lowers boiling point so its easier to get steam flash with higher water pump flow.

Re: Re-cored radiator and still loosing colant
 

Call it a myth if you like, but I have personally experienced this problem when I switched from an old original radiator to a new brassworks radiator. A thermostat solved the problem.

Re: Re-cored radiator and still loosing colant
 

I reread my post and realize it sounds kind of arrogant. Sorry about that, didn't mean it that way. Just trying to make the point that in order for coolant to be ejected from the system, something has to expand. Water expands I think somewhere around 1600 times in volume when it turns to steam so it doesn't take more than a few drops of coolant turning to steam to cause a major expansion, and lots of lost coolant.

Re: Re-cored radiator and still loosing colant
 

While that sounds correct and logical, I too have experienced the same thing as Bill. My original 1928 radiator lost coolant out the overflow tube until I flushed the block and radiator. Now I can drive 50 and not loose coolant.


My 1929 with only a 2 row aftermarket radiator would loose a quart or two in 10 miles. I pulled that radiator and installed an original.