MattD

Hi,

The car is a 70 Cutlass S, it has the original brass radiator. It was overheating so I put a new good thermostat in, but it was still overheating. I took the radiator out and looked inside, lots of corrosion on the tubes. Just on the few tubes that I can see there is one completly corroded shut, I'm sure this is the cause of the overheating (anti freeze not flowing through the radiator). So I'm taking the radiator to a radiator shop tomorrow to have it rodded out, and see if that fixes the problem. Anyone else have this corrosion problem before? Click on pics below:

oldcutlass

You might consider flushing your system prior to douing that as the inside of your engine will have alot of stuff in it also!! After your flush then I would take the radiator to the shop.

costpenn

You will amazed at how much cooler your car will run after you rod that thing out or replace the core.

I had a 1970 442 years ago - ran at the 3/4 mark on the gauge all the time even with the air off. The radiator looked perfect - none of those rusticles hanging off the ends of the tubes and no leaks. I changed water pump, fan clutch, flushed system, thermostat, nothing helped. Finally out of desperation took the radiator to Centennial Radiator here in Dallas - who the owner of just happened to belong to our club. He called me a couple of days later and said the radiator was 85% percent plugged up with what he called "casting sand" - a fine brown sand like powder. He again owned the place and knows something about radiators and swore it was sand from the block or head casting process that must of come loose when I rebuilt the engine. Needless to say, after that it ran at or below the 1/4 mark even with the air on in Dallas. Good Luck!!

svnt442

And when you re-install it make sure to use only distilled water and not tap water. That build up looks to be from the minerals in the tap water. If it's bad enough you might be in need of a re-core.

rustyroger

Maybe I have a fixation about recoring radiators, but in our local American car club I have had to pretty much bully my buddies into getting their radiators recored to fix overheating/mystery coolant loss issues.
Mostly they don't want to hear bad news that will need £££ to fix and try flushing/removing thermostat/adding extra fans/hoping it will go away etc.
But getting the radiator recored cured the problem in all cases, from memory a Dodge truck, Plymouth Barracuda, Gbody Olds Cutlass, mk6 Lincoln, '79 Olds Delta 88 diesel, two Ford day vans, AMC Rambler and a Pontiac Firebird. Not mention lots of mainstream British, European and Japanese cars. This in England when temperatures over 90 degrees make the national news .
It looks to me like your core is also junk, as mentioned in other posts dont forget to flush out the block before fitting the new radiator, if the core is blocked with crud there will be a lot more in the block and heater circuit as well.
Refill with a 50% quality anti freeze solution for corrosion protection and you should be good to go.
Dont neglect to look out for other problems such as collapsed hoses, bad thermostats as well as many other causes of overheating.
A large book could be written outlining all the causes of engines running hot but with older cars bad radiators are the most likely cause.

Roger.

BlackGold

I agree with Roger, that the single best thing most people can do to solve their cooling problems is to recore the radiator. Just make sure the new core has as many (or more) tubes and fins as the original.

It really doesn't make much sense to "rod out" an old radiator. To do so requires the shop to unsolder the side tanks -- same as if you were recoring -- and then clean every tube. So the total labor is higher, and you still end up with 40-year-old tubes and fins which probably still have at least a thin layer of gunk and/or oxidation on them. Why not go new?

I recommend recoring over simply buying a new radiator because 1) you can get a better quality core, and 2) it can be assembled by someone you trust instead of someone making $3 a day down in Mexico.

OLD SKL 69

That definitely looks like its in need of a recore. I also prefer recores over chinesium replacement radiators.

MattD

Thanks for the replies. The guy at the radiator shop said the radiator was beyond saving, like a few of you guys said. He said it could be recored for $480.00, but I ended up getting a brand new three row brass radiator for $210.00 ?? I will definetly save the brass tanks from the original though.
Also I did flush out the rest of the anti-freeze. I found two hex bolts on the bottom of the block that emptied out 1 gal out of each port. The anti-freeze wasn't as dirty as I thought it would be though.

Matt

Funkwagon455

I just returned from town with the radiator from my '70 wagon, the core was deemed too close for a thorough cleaning. They installed a new four row copper core (made in USA) for 4 $100 bills. It looks new, and should provide many years of worry free driving in Texas summers even if stuck in Dallas traffic. The peace of mind for my family is worth the money, the protection for the 455 makes it a wise purchase for the long run.

MattD

Supporting US manufacturing and getting a quality product, can't go wrong there.

Matt

71CutlassSupreme

this is SUPER helpful info. i'm a bit car dumb, can you explain what the process is to "flush out the block"
Also, if i get a new radiator, do you guys recommend a specific company for our classic beauties?

Tony72Cutlass'S'

Even if you drain the radiator. There is still going to be fluid left in your engine block.

So you're going to need to tip the car foreward to drain more of the fluid. It's described in the CSM under the engine section where you need to remove your heads. Since you heads are full of fluid as well.

Miles71

The radiator on my 71 supreme is original and judging by the looks of the stuff inside, the liquid maybe 10-20 years old. I have only had this car for a few weeks. The tubes inside look better than MattD, but not by much. Since I need to keep the costs down, I'll try to avoid replacing the radiator this year. The heater core leaks bad and has been bypassed. I flushed the radiator once, and I'll do it again after I put in a new core.
I think I will try the distilled water and 50/50 when it's all done.

Lady72nRob71

And with the block plugs out, use a garden hose and force water in from every port there is and let it come out of each one, too, blocking the lower rad hose sometimes with a rubber ball.
The idea is to stir up any settled crud and wash it out.

rustyroger

Can't improve on that, keep on until clean water comes from everywhere. Be sure to do this before you install the new radiator so you don't put crud back into it.

Cant help on good suppliers from here, plenty of Texas and Houston based members here who can.

Roger.