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Does anybody have a favorite fluid they use to flush their radiator? It occurs to me that the products for today’s cars may not be optimized for cleaning out the old honeycomb radiator on my ‘28 443. In the past I’ve just used the Prestone stuff.

https://www.amazon.com/Prestone-AS105-Radiator-Flush-Cleaner/dp/B00B99U088/?tag=drive09e6-20&asc_source=browser&asc_refurl=https%3A%2F%2Fwww.thedrive.com%2Freviews%2F27899%2Fbest-radiator-flush&ascsubtag=0000TD0000027899D1180071320240408020720

Does your car overheat due to a clogged radiator? If not, I would not use any flushing compound due to the possibility of causing leaks. If you have an overheating problem, I would try flushing the radiator and block with plain water first, and make sure your water pump is not leaking at the seal. Water pumps can leak air IN when the engine is running, and mimic overheating and boiling due to aerating the coolant.

Spencer, safe long-used method of cleaning complete cooling system is, heater on to flush that, too, dumping two lbs. washing soda ---not baking soda-- Arm & Hammer offers both, and a quart or two of kerosene. Drive 15-20 miles with that solution, then drain hot. Use a straightened coat hangar or welding rod to ream around when the block drain plug out while radiator cap removed to enhance flow.

T h e n open your radiator pet cock. After block's cooled, flush with garden hose engine off until just clear water comes out block, then reopen radiator petcock.

If it's been a long time, you could go for another 15-20 mile drive with just water, nothing else, then drain as above again. But this time, once block cool, refill with reverse osmosis water and corrosion inhibitor like No-Rosion.com or Red Line Water Wetter. Use antifreeze o n l y if your car will be exposed to two consecutive nights of a hard freeze, 30 or below, or if your car has air conditioning, in which case even in LA or Phoenix in August you need 15% antifreeze to protect your heater core from freezing.
We usually avoid Whole Foods because their prices are for the birds, but they do sell reverse osmosis for 49 cents a gallon. Bring your own jugs, self serve.

Never use soluble oil, an outdated practice, according to a Chrysler engineer member of the Auburn-Cord-Duesenberg Club in their monthly bulletin decades ago. It, and antifreeze, leave heat transfer-inhibiting film on cooling system passages, the last thing you want. Slightly off subject, but characters polishing aluminum cylinder heads miss the point, because they're reducing surface area, which helps dissipate heat.

Terrific synopsis of cooling system care on the tech link on norosion.com. If you order some from No-Rosion, tell Jay Ross that Mike, '47 Packard Super Clipper, Walnut Creek, CA, referred you. Product originally made to protect the hellish environment of terribly expensive industrial cooling towers. Jay's old car friends asked for some, and the company took off.

Assuming your thermostat and timing okay, you should be fine. Some of us added a stand off for our rear block drain plug. Certainly on the 356 engines, that plug's location near the starter and dipstick not one of Packard's smarter moves.

Hope everyone got a glimpse of the eclipse. Next for us in the contiguous States August 23rd, 2044, during which your cooling system should still be just fine if serviced as above.

Good explanation of what you experienced in your town or state:

https://www.washingtonpost.com/science/interactive/2024/solar-eclipse-view-cities/

Quote:
My partner at home in California where it is far from totality said that it got slightly dimmer out for a very short while but here in the High Desert of Central Oregon where I am at my shop, it's totally and heavily overcast so if there was any dimming at all, it wasn't noticeable. For the last total eclipse, this area was in totality even though the closest town of Terrebonne was not so we made it a point to be here. It was during some very heavy fires with lots of smoke and usually virtually no visibility but the winds changed for a while so for that brief time it was very clear. We could see the shadow of its edge coming across the plains, then the other edge when it was passing. It got noticeably cooler and the dogs were confused not knowing what was happening so they hid under the deck. Absolutely incredible!

Thanks for the responses.

TxGoat: I do have a bit of a somewhat persistent overheating problem. It consistently runs on the verge of overheating, turning to overheating on occasion in the hot weather and persistent traffic that Denver has to offer much of the year. So I’m looking for ways I might address it. I will be sure to look for a leak at the seal before going further but I’ve never noticed this before.

Su8overdrive: thank you for the VERY detailed explanation of this process. Living in Denver I do need antifreeze in the winter, although I like to switch out to water with some no-rosion in the summer and it gives me decent results, although the problem does persist. Also a question: when you specifically say “to ream around when the block drain plug out” — pardon a possibly dumb question but I’m not sure what the block drain plug is. Also, I will be sure to mention your name, too, if I have a chance to talk to the guys at No-rosion. I have ordered from them in the past. And will also check out write up.

Also looking into timing issues, all hoping to get it running a little cooler before the summer weather really starts to put stress on it.

I hope you enjoyed eclipse yesterday - there wasn’t too much to see here in Denver, it just felt like the sun going partly behind the clouds for few minutes.

Spence (and any others similarly flummoxed), here's a shot of where the rear engine block drain plug is on my 356-ci-engined car. My long ago owned 282-engined '40 One-Twenty and 288-engined '51, and a friend's '53 327 about the same location. If memory serves, about the same on a 319 and 384 of the '30s. Instead of the steel plug, we inserted a brass stand off drain.

No heroics involved, just poke around far as you can with a long piece of bendable wire coat hangar or welding rod in case you've accumulated any crud toward the rear of your block.

The eclipse didn't dim our sunshine out here in Kaleefornyuh, even tho' at its totality in Mazatlan, Mexico, it covered at most a third of the sun from our vantage point in the East Bay.

Absolutely, please tell Jay Ross that Mike Scott, '47 Packard Super Clipper, Walnut Creek, CA continues to sing his praises. Good man, good product, deserves our business, as do

Mike Grimes at Max Merritt, (317) 736-6233, ext. 103, mike@packardparts.com;

Jeff Adkins 1935-56 mechanical and electrical parts only (707) 792-9985, packardguy54@sbcglobal.net;

John Ulrich 1928-47 parts (510) 223-9587, julrich2847@att.net;

Mike Chirco Tucson Packard (520) 730-2246, cell (520) 275-4623, joe@chirco.com,

and others i've urged us all to patronize, who go the extra mile, have the Right Stuff.

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Over on the AACA Forums the use of Evaporust has been promoted by a number of their Forum Members, here's a LINK to one such thread where Evaporust was used. You can also use their searh function to find other threads where Evaporust was used.

Evaporust now has a product that is specific to flushing radiators and engine blocks.

Prestone "flush" is plain old TSPP = tetra sodium pyrophosphate. Available at most hardware/bigbox stores. An alkaline cleaner that's good for steel, etc. Aways want to be alkaline with iron, and not too strong. More iron can dissolve at high pH ~13, than above 7. (Iron only, not good for aluminum!) There's a curve for that.
I'd just flush it not running with the hose in the cap and drain open until the water comes clear, then clean it with flush and running to heat it up. Drain, flush again, and drain it dry. Can blow some air through it to get the last and then add the 50/50 antifreeze. I use DI/distilled water to mix as the premix is more expensive, and tap water can put hardness, pH, which can lead to deposits in the system/breakdown of the EG. I did that on the '49 and then found the hose neck was rotted and had to be repaired. I tested the thermostat to make sure it was correct and opening. One pin hole and they won't work. Capsule has to be intact. It would idle for an hour with no change in T. It had sat in a field for at least 5 years and not ran for a long before.
Old radiators have a heavy solder content, so PbO layer shouldn't be disturbed with what you clean it with.
Back in that day, '28, alcohol was the antifreeze of choice, but it boiled out overtime and had to be replaced frequently.
The modern anticorrosion inhibitors in the EG antifreezes should be sufficient to protect what you have. Change at about 5 years.
It's hard to say what or if the "verge of overheat" is caused or from as designed. These radiators are not pressurized, so boiling will be about 212 or so at sea level. Since you're operating in high elevation,(Denver) that could be your problem. BP goes down with altitude. It's really not a problem until it comes gushing out and loss of fluid. If it boils, then you get steam pockets, and steam is not a good heat transfer medium and superheats, pressure rises in block, and then it expands and moves everything out. Not good for the lubricated side. Pressurization inhibits that nucleate boiling issue. {They weren't too heat transfer swavvy in '28.}
The air flow is more critical to remove the heat than the cooling side film, unless flow is retarded due to sludge, plugged passages, or weak H2O pump/if not a thermosyphon system. Check your belt and fan and any missing air dams. Impellor may have rusted over time. Something to check as is the thermostat for operation or blockage, also.
Fine surface roughness has little or no impact to HT area as it's within the laminar zone. The fins are what help. Plus not much air moving inside the engine compartment.
My personal rule is not to experiment/play around with hard to replace antiques and modern 'solutions' without exhaustive testing and verification. There all kinds of hearsay suggestions out there without proof, but sworn by. Not saying they aren't good, but without documented proof - won't stand up in court! One reason I usually don't recommend products and certainly qualified to do so.
Definitely don't run just RO/DI water without any inhibitor in the system, even for short runs. Water itself is corrosive. Old cast, gaskets, etc are of unknown condition, so you don't want to open up any faults that were sealed by corrosion products... When one operates a 'million ohm' water system, they use non-metallic pipes, etc. so it doesn't pick up any metal ions.

Mike (su8overdrive), thanks for the further detail on this. There is no such drain plug on my 443’s engine block. I currently have the water jacket off and have given that area a thorough cleaning. If my only real method for draining things after your flushing method is via the draincock do you think the method you described will be effective? I’m going to swallow my pride here to admit a mistake I made last year in that I used tap water rather than reverse osmosis water, so I am concerned there may be scaly mineral buildup on my radiator fins. (I was sure to use No-rosion at least to prevent rusting). (Also I do know Mike G at Max Merritt and have talked to him several times, Mike C at Tucson Packard too - they are both great. I’ll be sure to reach out to the others you mention.)

I also do see some rust throughout my system and so think a flush with Evaporust might also be productive for getting stuff out of the system. The thing I’m discovering with this car is that, while it was generally well-restored and well maintained, it seems maintenance did slip some in the later years of the former owner and so I’m just trying to get systems back into top operating condition.

Fish’n Jim I have been checking a number fo the things you mention. Water pump seems pretty good, fan blows well. One area of concern is that a small dripping leak seems to occasionally occur in the radiator (about 2/3 of the way to the top) after longer periods of driving in hot conditions. I’m not sure what to make of that. I’m also not sure how to check for rusted air dams or what a rusted Impellor is (is this part of the water pump?). I appreciate all the detail you provide, I hope you’ll excuse my very limited knowledge on all this.