Projects New Radiator

I have been driving my convertible since 2001 now and have fought overheating problems since day one. The 455 Olds engines normally don’t have those problems. I had a Griffin aluminum cross flow radiator in it. This spring I replaced the water pump with one that Mondelo sells. They said it was cavitation causing my problems. This helped a lot but I would still like it to run cooler.. I ordered a tri-flow radiator, supposed to drop the temp 10-20 degrees. I am in the process of putting it in now, I had to make a bunches of changes to do it, and should have it done tomorrow. I hope it does what they say it will do.

 

Not sure exactly what your "overheating" problems are but having had a couple of those in their original chassis and more 350R's than I can count they do like to run hotter than what a stock late 40's Olds would.

 

At one time this would run 235 degrees down the highway, that’s way too hot. The water pump got it to a little over 200 degrees but the outside temp was around 90. I’m still worried about what it will run with temps in the mud to upper 90’s

 

Someone else here has a '53 or so Olds with a 455 and a similar overheating issue. I forget what his user name is.

 

post a pic after install - have a full fan shroud?

 

If you are running 235 degrees at highway speeds something is really wrong. What is it like in heavy traffic and stop and go driving. As Jalopy suggests, do you have a shroud and all the stock sheetmetal used to duct air thru the radiator?

 

How about your pulleys?, The 350 in my 1939 Ford convertible ran hot every time I slow down and was in traffic, the Griffin aluminum radiator was part of the problem, I posted a few days ago about have of the cooling tubes being filled with epoxy, but another piece of the puzzle was the pulleys, The water pump pulley was the same size as the crank pulley and it was circulating the water too fast.

I found a smaller W/P pulley that helped a lot, with the new radiator, a 17" steel fan and the smaller pulley the car never ran hot again, even in pigeon Forge, Tennessee traffic and anyone how has ever been in that insanity knows what I'm talking about, it will try the best of the cooling systems. HRP

 

235 at highway speed definitely is too warm. You don't even need a fan or shroud at highway speeds. Remember the cooling rule of thumb. Hot at low speed - not enough fan or need a shroud. Hot at highway speed - not enough radiator. I've never been impressed with Griffin radiators. I only use copper/brass radiators as they have a higher cooling coefficient then aluminum. All aluminum radiators do for you is they weigh less.

 

455 Old's had big radiators.
I had to replace the radiator in my RV, couldn't get a 4 row like the factory one so I put a 3 row in it.
Now pushing it hard at highway speeds it will start getting a little warm.

 

I have factory pulleys on it, and a good fan shroud. I have a few things to put back on and I will take some pictures and post them. After all the work I just went through I hope this does the trick. Thanks for all the ideas to look at.

 

I hope the radiator does the trick. HRP

 

Here are pictographs the shroud

 

I'm sure the flathead guys, and others, will take issue with me, but the fact is, the greater the coolant flow rate, the better the thermal performance will be. Ask anyone that designs heat exchangers. A poorly designed water pump impeller is more prone to cavitation as speed is increased, but this is not typically the problem. I'm a bit confused by this post; if you replace the pulley on the water pump with a smaller one, the pump will run faster, not slower.

 

Water pump pulley is smaller diameter than the crank pulley

 

The pulley is just what came on the engine from the factory. All olds engines use the same pulleys 350, 400, 455 all use the same pulleys

 

The tri flow radiator coolant makes 3 passes through the radiator. So if it does what it’s supposed to (just like making the radiator 3 times bigger) this should make it run cooler.

 

Theresa and I took the convertible to Dairy Queen for a treat then took it out on the highway for about 20 miles. No big change in the temperature it still runs about 210 or so with the A/C on but drops about 10 degrees with it off. I guess this is what I’m going to have to live with

 

My bad, the water was circulating too slow. HRP

 

What Rpm are you at highway speed?
How is timing set, do you use the vacuum advance?

 

I run a wicked little Mondello 455 in my 442. 11:1 CR, aluminum heads, roller rockers/cam, tons of timing, no vacuum advance, MSD distributor, 4 row aluminum radiator, twin electric fans in a custom shroud. A custom spral controller turns each fan on and off as needed. It had an overheating issue, had is the operative word. She can idle in traffic all afternoon on a 90 degree day now and never get hot. I get hot (no AC, rag top) but she stays nice and cool.

I am not a proponent of electric fans so don't grab your pitchforks and torches, BUT running and dependable beats looking at a mechanical fan when the hood is open and like @HOTRODPRIMER said in another post, the hoods look better closed anyway.

From one Olds man to another, I hope you cure her ills.

 

Yes it has a spring inside it. When I replaced the radiator I replaced the hose too , I had to use the spring, the new hose didn’t have one

 

Thanks, I agree with you, I MSU have to run an electric fan. I have always thought you could fix heating problems without using one, but maybe in this case the electric fan is the only cure for it

 

@EnragedHawk went thru heating issues with his 53 olds with a BBO. Here is the link to his posts. page 5-9? speaks of the overheating issues. FWIW

 

Thanks for the link, I’ll have to check it out!

 

I don’t have a tach but run 3.08 rear gears, so it can’t be too bad, timing is set to factory specs, the HEI distributor had the advance curve set to match the original points distributor

 

That's the guy I was thinking about. I think he got it sorted out.

 

Take this from a flathead owner.
Some thermostats impede the flow in a coolant system. Temporarily remove them.
Be absolutely positive your advance is running at spec.

Also a lean running engine will run hot. Have you tried increasing jet size or have your exhaust analyzed?

Another thing to remember. Your fan, shroud, pulleys and radiator may be perfect. But if the setup is impeded by lack of space for the air to exit your system will be ineffective.
Finally. And Ugly. A cracked block will behave this way.
Good luck hope to see you get it.

 

When I talked to mondello they sold me a restrictor to use instead of a thermostat, so that is in the engine now.

 

I would try removing that restrictor.
You need maximum volume flow. Coolant Moving too fast through a system is a wife’s tale. I believe many confuse that with impeller cavitation.