Transmission Cooler Fittings for replacement Aluminum Radiator

[djwarner]

After finding my original(?) radiator had been re-cored previously and in bad shape, I opted for an all aluminum radiator available on Ebay made in the PDRC. Got it in today and didn't look all that bad but Inoticed the Transmission Oil Cooler fittings were welded in place. They are appear to be male metric flare fittings. M14x2 I guess.

Needless to say, they don't match what is there. A quick check of our local parts stores came up empty.

I'm sure I'm not the first to face this. Any success stories out there?

[Stanley]

Was baffled when I got my aluminum radiator from MSA a couple years ago. Wasted a lot of time going to hardware stores. Called MSA and they didn't know. Finally took it in to Mr. Hose - they identified it as AN dash-6 and fixed me up with the female fitting and a hose barb adapter. Don't know if yours is the same.

[djwarner]

Thanks for the lead, Stanley. Went to HOSE BOSS in Tampa today and picked up a Brass fitting with a hose barb. The other line has a 6 inch metal line that was flared to a flat face rather than a cone. I figured I will cut off the flat and re-flare the line. Unfortunately, HOSE BOSS didn't have a matching brass flare nut and I settled for two piece steel unit with very little room for the flare.

Later I stopped in a Home Depot and they had exactly the flare nut I was missing. Should have stopped there first and saved myself the 45 mile trip.

Been looking for advice on protecting the Aluminum Radiator from Electrolysis. First thing I learned was to always flush and refill with new 50-50 coolant. Second, if you are not using premixed, use distilled water to dilute the concentrated stuff. New 50-50 solution provides enough silicon to coat the interior of the radiator to prevent corrosion.

The third and most important step is after you've filled the radiator. With a digital meter capable of displaying down to tenths of a volt, measure both AC and DC voltage between the negative terminal of the battery and the coolant. Measure with the engine running and with various other systems on and off. You should read 0.2 volts or less. 0.3 volts will cause corrosion and 0.9 volts will lead to rapid failure.

Voltage leakage is usually caused by flaky wiring and/or grounding. AC voltage is caused by electrical noise coming from somewhere in the car.

[John Coffey]

The 50-50 coolant mix recommendations are for cold climates. In Florida you can easily run a 25-75 mix (coolant-water) and have plenty of protection. And the coolant does not coat the radiator or engine coolant passages. It just makes the water less conductive.

[djwarner]

According to what I've learned, there is about 250 PPM Silicone in the concentrated Antifreeze, about 125 PPM when diluted. It is the Silcone the lays down on the aluminum for corrosion protection. After its been in the system for a while, the Silicone in solution is reduced. Thus when you put fresh aluminum in the system without replenishing the Silicone, the radiator is susceptible to corrosive attack.

A 50-50 solution also raises the boiling temperature compared to a 25-75 mix, a desirable trait in FL.

[John Coffey]

Me being a little nit-picky...

There's a big thread on HybridZ about the L6 cooling system. To summarize, pure water has a higher heat capacity then a water/coolant mix. What that means is that the actual coolant temperature is lower for the same amount of BTU input with straight water. Increasing system pressure increases the boiling point of water by 3 degrees per PSI. A typical 15 psi cap gives you boiling point of straight water of 257 degrees. A 20 psi cap (which your aluminum radiator can handle) gets you boiling point of 272 degrees. The actual boiling point is lower then those number due to localized hot spots (the exhaust ports and valve seats) causing nucleate boiling. Most racers will run straight water with Redline's Water Wetter for corrosion resistance and its surficant properties - and because race tracks don't allow any glycol style coolant.

[djwarner]

I agree with everything you said, John.

The reason for the new radiator is the poor seal of my already re-cored radiator. It would only leak after shutdown and the waterpump no longer circulated water through the radiator. Hot spots in the engiine would raise the temperature enough to boil the mixture and force coolant out the leaks from the pressure rise.

While I haven't run my new VintageAir system in the Florida summer yet, I haven't seen temperatures exceeding 190 degrees with the engine running. (I have recently calibrated the gage so I'm confident in the reading.) I would expect with the additional capacity of the aluminum radiator, I will not see temperatures ever reaching the boiling point with the engine running.

Our old coolant systems are different than modern ones with coolant recovery systems. The newer systems are expected to run without air (or steam) in the system. As the mixture warms and expands, the cap relieves the pressure to the external tank. On shutdown and cool off, a vacuum is created and the coolant sucks back in from the tank.

Our systems were designed to have some air in the top of the radiator and to simply vent excess pressure. This is why we often find the radiator cap stuck on by the reduced pressure when the system cools down after venting. This reduced pressure will actually lower the boiling temperature.

As for the ability to carry off heat, specific heat as it is called, this is only one part of the equation. The ability to transfer heat to the radiator and the ability for the radiator to transfer heat to the outside air and the rate at which coolant circulates through the system are also significant factors.

Since I'm running a more or less stock engine, I won't be seeing the heat loads of out racer friends.