The block drain plug on the 300 often become part of the block. The nice thing is they do not need to be removed. If you remove the thermostat and lower radiator hose you can fully flush the block. The trick is to be able to back flushed using the water pump lower radiator hose inlet.


I see coolant filters have been mentioned, while optional they do have the upside to completely clean cooling systems and longer heat exchanger life. The basic kit can be had at NAPA #4019 paired with a #4070 filter. This filter is compatible with all coolants. The other filters are SCA pre charged.

 

I removed my e. fan and pulled the radiator. With it on the ground I plugged it and pressurized it with air, squirting soapy water all around, and could not find a leak. I had a new Summit rad. sitting here in the box, but put the old one back in with a new thermostat, replaced and doubled the hose clamps. I also bought good fluid and diluted it with 50% distilled water. Now it is sealed and humming along at 192*. And the best part is that I get to send the rad. back to Summit and get a refund! I like that.

 

Almost a month has passed since I posted about my Summit radiator. Out of the blue it is leaking badly. Can't drive it. This is the THIRD Summit radiator, each the exact same model, that I've had in it. Each lasted about two years.

Today I ordered the old copper and brass style. It will take a bit of fab. work to install, and a new bottom hose, but it should last a decade. Time will tell.

 

Who did you order the new radiator from? What brand?

 

I believe this too is a Summit radiator. I hope their copper/brass is higher quality than their aluminum.

 

I am not an expert on coolant antifreeze and all that compared to you all and was mind blown by it and learned a lot too, however the only one brand I ever used for 40 years is Prestone (concentrate) for all my rigs since I had 'my own' first vehicle in 1981 when I obtained my driver license at 16, while having to learn how to properly maintain and put money into a vehicle to run it for the long haul and keep it, while cheaper in the long term (and was raised California dirt poor while hustled and worked but STILL budgeted for vehicle fluids, oils, coolants which was never neglected) - then again, every vehicle I ever owned were equipped with brass radiators - also as to this day I never ran any aluminum radiator in my rigs.....

Year round I run a 67%-33% mix -or- 2 gallons Prestone concentrate for every 1 gallon distilled water (as I live in the arctic region), and now only run 180 degree F thermostats year round.... In past years (Pre-2000) during the winter months (Nov thru Feb) I ran anything between 192 to 205 degree F thermostats but not anymore....

Although I wish I had access or capability to power flush a block, my normal interval of a complete change and replenish fresh coolant is generally every two years draining radiator and block, sometimes three years depending how fresh the coolant looks and what the coolant tester mix shows (OK if it still reads -50 F below or colder around the two year period and the threshold for me is replacing all coolant if the tester reads under -45 F below in the two year period)....My brass radiators and engine block hardly shows any minimum amount of scaling.

All my radiator replacements (new) over the years are as follows :

1989 - 70 Thunderbird - 4 core 40 row - BRASS
1998 - 70 Dodge D200 - 4 core 38 row - BRASS
2003 - 70 F250 - 3 core 30 something row - BRASS
2010 - 73 Lincoln Town Car - 3 core 30 something row - BRASS
2014 - 73 F100 - 3 core 30 something row - BRASS
2017 - 75 F250 - 3 core 30 something row - BRASS

Out of these 6 replacement radiators, I only had to take ONE to the radiator shop only ONCE (the 73 F100) after dropping a screwdriver with the engine running upon fine tuning the air mixture screws on the carb, and somehow hit the fan blade and ricocheted off the radiator by springing a leak on two of the tubes and had the radiator shop repair that....that mishap was my demise, and not manufacturer defect related.

All these years running these replacement brass radiators have not given me any defective type of leaking core problems (other than two of them had like a mounting bracket come loose off one solder end at the tank out of the four mounting points)....just me personally I prefer brass radiators for all my rigs as they are durable and reliable for me (my youngest rig ever is still my 76 Lincoln Mark IV as I never owned anything newer)

I know there are hi quality aluminum radiators and el cheapo brands, and just like the thread starter had stated - someone else I know decided to not run a brass radiator anymore on his Dodge Truck when he had to replace it and went with aluminum at the parts store because it was 'three times cheaper'....
The radiator was still under warranty even after the fourth replacement in five years (some brand O' Reilly's was selling), as he was just fed up with the problems he had with them, taking his truck apart again and again during the winter to pull the radiator out (with no garage), bummin rides to the parts store back and forth and all that and I am pretty sure he was running the right coolant too.....finally shelled out the money and went back to installing a brass radiator.

I see too many aluminum radiators go bad for various reasons but mainly cheap ones or by collision damage or by not using the correct coolant which would be like 1 in 20 that I can tell the core covered in massive coolant.....in that particular order -

One bin container completely full of bad aluminum radiators shown - which was empty 10 days ago -




For those who still run aluminum radiators in your old Ford Trucks that are trouble free - you all are definitely doing something right !!!

 

I changed back to the copper/brass down-flow type. The aluminum rad. I had had a peculiar design aspect: The lower 6" or so of the side tanks was angled, so the bottom hose fitting was installed above that angle. That meant that the lower 6" of the radiator was dead space. Anyway, I really like how with a top and bottom tank, it does not push the radiator into the engine compartment and take up needed space.



Above is what I removed, after using 3 of them, and them lasting about 2 years each. Below is the radiator I put in it.

https://www.summitracing.com/parts/sum-382013

 

Hmmm, not sure a two core with .5” tubes will do very well cooling. Let us know how it works. The price is definitely good.

 

Hey there. That was a concern of mine as well. It was oem for F250's of my era. I do, however, like a bit extra cooling in reserve. This is for a 4.9, with 25% fewer cylinders to cool. But you're right, a bit larger would have been better, but I was in a time constraint situation.

 

Hopefully if they used such wide tubes there is turbulators in them to slow flow and allow contact time. One would hope they did or else your going to have very little contact time to exchange heat.

 

Hey Gashog. I thought you might turn up. Can you tell me what turbulators are? Is that some sort of swirl grooves in the tubes?

 

They are designed to induce turbulence to the fluid. They slow fluid and allow proper contact time and heat exchange. The are also useful in slowing down tube header erosion. They come in various shapes and designs. Radiators with these in them are not eligible to be "rodded" out or cleaned. Ford used these on the 6.9 and 7.3 IDI trucks because flow was too high. You find these in industrial applications but I have seen lots in replacement radiators also mostly as the manufacturer sees fit. Ford actually employed the balanced flow Robertshaw thermostat originally to slow fluid flow. The balanced design worked very well, then they switched in the 80's to the cheap wax pellet disc.

https://flowkoolerwaterpumps.com/pro...=9125073354804

Variety of turbulators

Enlarged tube section turbulator inside

 

Thanks for the explanation. That is understandable.
I wanted to ask those with more experience than I about what size radiator would be good for my truck. I switched from a 390 to a 300 I6, so I have no idea what is a good size for this engine. I have a full size F250. Mostly, it is simply my daily driver, city, So. Cal., low mileage, but sometimes I haul/tow, and enjoy driving cross country with a decent load of camping equipment. I had an aluminum in it 26X19" core, 2 tubes of 1" each. It was a cross-flow. I run elec. fans and the fluid rarely got hot enough to trigger the fans. I assume the radiator was too large for this engine.

So, please give me an idea of the approximate size I should be running. Thx.

 

F-250 Restorer,
I have the stock radiator for my 1978 F150 Custom with a 300 I6. It is the smallest thing I have seen in our era of trucks. (My brother and I inherited out Grandfather's 76' with a 460 and the big 4 Row Rad.) I will try and remember to take a photo and see if I can post it of the small radiator. I have had no cooling issues here in the Texas heat, though I have never towed anything heavy with it.

 

So, I've been driving in town for a few weeks now with the 24.125" X 18" radiator. It has two rows of 1/2" tubes. On a mild day, just driving around the city, empty bed, with a 192* thermostat, the fan will come on just a tad over 200*, and can not cool enough for the efans to turn off. Wow. That equals 868 sq. inches of 1/2" tubes cooling surface. My old radiator was aluminum. It had 1000 sq. inches of 1" tube cooling surface. That is more than double the tube surface area, and it was aluminum, which may or may not dissipate heat better. The old radiator would drop the temp in about 2 minutes enough for the fans to turn off. This is very interesting.