Anyone ever used CLR to flush / clean a radiator

The coronet runs a little warmer than I feel it needs to. A tad over halfway on the factory gauge . I have not ckd with a temp gun or mechanical gauge yet....... But raise the hood and it definitely seems warmer then the Satellite does in same ambient temps
Ive already replaced thermostat with a high flow style

The car runs ok , But seems to run warmer the more you drive it.
Like sitting at light. it warms up a tad, but doesnt cool down once moving again . Like my Satellite does.
Timing is right , carb seems adjusted right .

I don't feel like it over heats ,,,,,, just would like to cool it down a tad . Especially before I get the air working here soon

Anyone ever used CLR to clean a radiator out?
Im thinking lay it on its back and fill it up, and just let soak for a bit. then flush and reinstall

Thoughts ???

I don't know feeling warmer is a good guide.

I would want temp readings.

and temps creeping up at a light could be a few things. clutch if you are using one, water pump or fan not deep enough in the shroud.

but if you are going to flush, I think this might be a better choice.
https://www.evapo-rust.com/restore-your-engines-cooling-system/
someone recommended it to me and I got a couple qts to try, just got it today, but won't have time to try it for a week or two.

No fan clutch as its direct drive. Fan blades are dead center in the shroud edge.

I was thinking pick up a decent mechanical gauge before doing anything to have a better baseline on actual temps

I tend to think if it was water pump it would cool down once moving again, at least a little bit.
My Satellite runs right at 180ish range with a Stewart components Tstat. Even on a 100 plus degree day even in traffic. It may warm up close to 200 at stops but cools right back down once moving. And the coronet feels warmer underhood than the Satellite does

When I first got the Satellite it would run warmer the more you drove it . And I did basically same thing. Flushed the radiator and block ( with garden hose and radiator in car ) Went with the stewart Components Tstat and it cured it

ps, the Satellite has an aftermkt mechanical gauge in it .

I've used Radiator Flush. I believe Prestone brand.

The usual questions apply:
What is the real coolant temp ? (mech gauge)
Hoses collapsing ? (observe running/hot)
Blockage in engine or radiator ? (water in = water out, test separately; for engine,with T-stat out)

Never thought of using CLR for a flush but in the past I've used the Prestone stuff.
Best is if you have a radiator shop clean it out (assuming there's one in your area).
Haven't had that issue for decades, since switching to distilled water w/Water Wetter and coolant.
But who knows what the prior owner did.

I’ve never used clr.

I’ve had a few engines that kept pushing casting sand into the radiator. No matter what I used or how many flushes, it would just build up and need to be taken to a radiator shop. High speed blasts would break the crud loose soon after. Especially sustained interstate flat out runs…

My thought is: With so many radiator flush products on the market, what made you jump directly to CLR? Not trying to be critical, just curious...
Personally, I'd be afraid of the potential affects of un-tested chemicals (in CLR) on the gaskets/sealants they're going to come in contact with.

Simple answer ....Was walking thru dept store and spotted the bottle. Thought.....will it clean a radiator internally.?????
.

Radiator will not be in the car . Im planning pull it and lay it on its back . Filling radiator only. Then flush several times becore reinstall in car.

I will head out tomorrow and pick up a mech gauge . Before doing anything but deep down have feeling its warm....at least warmer than i want ot to run

Oh...you said that but I assumed (I know) you meant a complete motor flush. On a bare radiator I don't think it could hurt.

What I may do is drain refill and add flush/ cleaner . flush again,

then pull radiator and fill it will cleaner only and let it sit a while.
the flush it seperately.
resinstall and go for a drive

Right now, car has 1 gallon coolant, then filled with tap water. new 160 Stewart Components stat . No water wetter of any kind
And if I were a betting man would say its over 200 degrees. ( I will know tomorrow afternoon ) And I know some say thats not hot
But its to hot for my tastes

Oxalic acid has been considered a good flush for more than 50 years.

https://www.astm.org/stp25166s.html

The evaporust special gell certainly looks interesting,
maybe after a first oxalic acid cleaning?

A video boroscope “snake camera” to view interior passages after a flush seems logical,
since their price has come down so much,
and they have so many uses.
The smaller than 9 mm camera diameter is very handy.

Bill, I would check the radiator with an infrared heat gun all over the radiator and make sure it is even everywhere. My '68 RR would be fine and if you opened the cap and looked in you would think the radiator was perfect. Go for a stop and go drive and it would lose coolant after it heat soaked when you stopped. Took out the infrared heat gun and the whole right/passenger's side upper corner had no or lower temp and was completely clogged. Re-cored it and no problems. Make sure with a infrared heat gun the radiator doesn't have bad areas and the temp is even. (didn't read all of the posts so if this has been suggested, oops )

Make sure your mechanical gauge is accurate before trusting it
I've seen and had some expensive ones that weren't
The first one was a race large diameter320 degree reading face Autometer mechanical temp gauge with the sender plumbed into the water pump housing next to the upper radiator hose thermostat housing, it would read 140 F when the water flowing into the radiator was less than my body temps were
The last street car I built had a Griffen copper and brass cross flow 4 core radiator that was a little shorter in height than the opening in the radiator support so some of the air would flow under it instead of all the air flowing through it It would get hot, above 220F, driving in town and not cool down when driving it at or above 50 MPH on the highways
I replaced it with a two core aluminum and it ran 165F in town and would cool down to 160F when slowing down on the highways on the off ramps
The next summer it was back to running hotter so I had the radiator back flush at our local radiator shop and that fixed it for that year
That motor was my first pump gas 400 stroker motor that ran on 91 octane pump gas here in Oregon. that motor made 612 HP at 5500 RPM before installed in the car, I used a low deck six pack intake with a set of 1970 440 automatic non CA carbs, that car, 1971 duster weighing 3450 Lbs. with me in it, exceeded my wildest expectations by running 10:69 at 124.+ MPH on Oregon pump gas with the air cleaner and full 3.0 inch exhaust system on the car with the Magna Flow 14x7 oval muffs, mounted behind the rear end the first time out
if it runs between 180 and 220 F I wouldn't worry about that, if it runs hotter or cooler fix it

Once you have the radiator all flushed out I would get a radiator shroud if you don't have one and a thermostatic clutch fan. Both those will improve on the cooling.

It has a shroud.
And i picked up a mechanical gauge today.
Already verified its accuracy on the stovetop with thermostat before installing in car

Your engs.may have different water pump blade counts 6 vs 8 just a thought.

i have used CLR to unclog heater cores in the car,pumped it back and forth with a drill powered pump,worked great,no problem

Update

Ive got the mech gauge on it .

Going in this morning temps ran right on the 160 thermostat. Ambient temps were in the 60s

Coming home in town driving it got to about 180ish, ambient temps were mid 90s
Once on the interstate temps crept up to the mid 190s range.
once off the hiway it cooled back down slightly to about 185ish

This is with a Stewart Components 160 hi flow stat , 1 gallon prestone antifreeze and the rest filled with tap water . It has a fixed blade aftermkt aluminum fan and stock pulleys

I can see the fan itself causing temps to rise in town stop and go driving ,,,,,, but should make no difference on the interstate speeds . I dont know what blades the water pump has on it


I have not just let it sit and extended idle to see where it goes yet



My Satellite with this very thermostat runs right on the 160ish range as long as its moving. Temps will creep up on it slightly but as soon as its moving again it cools right back down pretty quick .
This Coronet doesnt seem to cool back down like the Satellite does once moving. thus why Im thinking radiator flow

Bill an infrared heat gun will tell you something about how your flow is through the radiator. It should be "approximately" the same all over if it is flowing properly and somewhat cooler at or near the return/bottom, just saying.

Mike,

Im going to pull the ac condenser to ck the radiator like you mentioned. With the AC stuff in there . Im afraid theres not much room to get very accurate temp readings

when i worked at a Honda dealer in the mid 80's there was a big problem with the radiators and heater cores plugging up.the heads had problems also.
the quick fix was drain the radiator, add about 4oz of Qxalic acid, wood bleach, to the radiator, re fill and run the car at about 2000 rpm for a hour or so. then flush and refill.
it worked 90% of the time.

https://www.amazon.com/Oxalic-Acid-Bleaching-Wood-Net/dp/B001F2US4U

I can tell you from experience that CLR works NOTHING like it is shown on TV. The dip & clean demonstration they depict is a complete farce.

I will also say this: I had a 78 Super Coupe back in the later 80's & the engine always ran hot - something was not right with the cooling system, also the coolant always was brown even after flushing the system & using new coolant. Radiator looked good internally, but I pulled it anyway & had a radiator shop boil it out & pressure test it, then reinstalled along with a new thermostat & water pump. SAME scenario - running hot & dirty looking coolant. Finally on a slow day, we pulled the engine due to a freeze plug that was leaking - it was one of the ones that you could not do with the engine sitting in the cradle. So the plan was to replace all the freeze plugs with new ones, clean & paint the motor & the exhaust manifolds, etc. - reinstall. Upon knocking out the large freeze plugs on both sides, we discovered SO MUCH sediment in the passages - like mud. We hosed it all out & a LOT of crap completely flushed out pretty quickly & easily til the water ran clear. Installed new freeze plugs, painted the motor & reinstalled. This completely took care of the issue. I'll tell you this, there is no way you can effectively flush a motor that contains sediment unless you pull the freeze plugs. This was the ticket.

I would drain the system and go to Walmart and buy 3-4 gallons of white vinegar. It will eat the lime out of the entire cooling system. Very little cost and it works.

Tom

Ive not rulled out popping a few freeze plugs out

the coolant does turn a light brown color pretty quick


I know 190s is not hot.
But my fear is once the ac is operational and I get out on days at 100 temps, or more .,,,,,,, There is going to be a problem

This is what I was going to say, had this happen on many mopar engines. Adding bad hard water over the years seems to be the culprit.

Many underground mine electric motors have water jackets.

When the cooling water from the mine contains dissolved iron,
a tough to remove iron compound builds up inside the cooling water passages.

Muratic acid (HCL) was the “go to” way to dissolve and clean the cooling passages.

Muratic acid is dangerous in many ways.
Easy for me to believe not all gaskets could stand it.

The Evaporust special gel product was not available back then (1980s) and is interesting as it may be safer.

Video borescope inspection through freeze plug holes seems like a reasonable “investment.”

Above, if you’re laying on the ground a 50 50 mix of muriatic acid-water will clean it out, stay there it won’t take long. I have a tank I put block-heads in to ‘cook’ them free of rust, then another tank with commercial baking side to neutralize the acid. THE mix most radiator shops used back in the day.

Not sure why you think you have a problem.

185 is perfectly fine, in fact running a 160 thermostat in a street car is not ideal. It sure isn't what the factory specified.

Im well aware of this.

My concern is the temps seem to continue to rise on expressway speeds . Not to mention once the ac is operating whats that gonna cause .

I drove it in again today and plan to take it on a longer hiway jaunt to see what it does this afternoon.
I prefer it run cooler than hotter.
Especially when we wre getting into summer temps in the low 100s every day.

The factory was worried about block and ring wear with that recommendation, most motors will make more power at 160F operating temps. than they will with the same tune up at 180F

Have you checked the exhaust for restrictions? That would cause an increase in coolant temperature, especially at highway speeds.

Not really relevant to the issue, which is that running at 180 is not a problem.

But to put to rest your old wives tale, engines make the most power warmed up but with the intake charge as cold as possible. A real honest to goodness dyno test with real numbers and everything to back it up, not anecdotal stuff half understood.

https://www.motortrend.com/how-to/impp-1107-cooler-engines-make-more-power/

Exhaust is brand new. Removed headers and Went back to iron manifolds with 2.25 pipes from manifolds all the way to the rear bumper. He even put an H pipe system on it

Try putting a temporary chin spoiler under front bumper/radiator support & scoop more air through the radiator, not all body styles flow air the same through/around radiator/eng. compartment.

Drove it home again today.
Same results. going in this morning it runs right on the 160 temp of the thermostat. Ambient temps were mid 60s I think

coming home this afternoon with ambient temps right at 100 it gets to 160 fairly quick, little slower to 180 ish
But about 6 or 7 miles on freeway at 70 mph it runs up to a clik under 200. ,,,maybe 198-199 range.
Once off hiway it takes maybe 2 or 3 miles and cools back down to upper 180s range

Is the radiator correct for the engine-car? Is coming ‘home’ more uphill? Or change of altitude? At speed the fan and shroud mean nothing, you have airflow. Stopped up, fins closed off or not enough surface area the radiator isn’t getting rid of the heat, that simple. A Hi VAC friend told me once that a temp of 210 can drop 30 degrees to 180 faster then 180 to 150 degrees, outside temp differential being the same. So when you say up at 60 and back at 100 that’s a 40 degree change. It’s harder to cool at 100, your water can’t get any cooler than 100, (outside temp) give or take a few degrees. So my guess you have radiator problems, not fan, not shroud

Running warm at highway speeds is usually a water flow issue.

Poor flowing radiator, wrong pump pulley or pump, thermostat not fully opening, etc.

I've used vinegar to flush the cooling system, remove all water/coolant, block drains too, fill with vinegar, warm up, let set overnight, flush and refill with proper coolant mix.

One thing I didn't see specifically addressed, is your exhaust flapper opening as it should?

exhaust valve is frozen open position

altitude change is approx 800 ft, rise in the afternoon . This is spread over 25 miles give or take. So I doubt thats enough to make a difference My other car will never get over 180 MAX the same exact route using this exact thermostat

Im going to pull the radiator this weekend and ck it over. also plan to pull water pump and ck vane count . , while I have it drained . Might pop a few freeze out plugs and flush the block as well
All pulleys are factory stock

My gut is telling me Deep down I have a feeling its radiator flow issue.

And will add, airflow restricted ( radiator or condenser full of bugs etc.) blocked or missing seals ( hood, sides etc.). Inefficient or too small of a core.

is this a new problem? a bit more info on the history, engine size, 22 or 26" radiator etc. might also help

I just recently bought the car and only drove it twice before taking it apart to repair a worn front suspension and get rid of the headers. and fix a bunch of general issues underhood . all new belts, hoses , plugs and wires , cleaned and detailed etc etc
so I cant say if it ran warm on previous drives or not

Engine is a late 70s 440 . pretty much stock ( no idea if standard bore or not ) stock auto trans and convertor as far as I know.
Radiator is some kind of aftermkt 26" 3 row core

I think I have base timing set about 15 degrees ( dont remember to be 100% sure but thats close Im sure of )

Since I now read this is happening at highway speeds I am going to say you need more capacity. 100 degree temperatures would have worked the system when the car was new. I had an issue years ago with a car I pulled a lawn mower around with. Never had an issue in town, but when I started pulling it down the interstate it would get hot. Installed a 4-row radiator and never had another issue.

Tom