Sparky365HP

After several years of hot weather concern, I'm about to purchase a "Be Cool" aftermarket radiator for my slightly modified 350.
Mild cam,Edelbrock Performer Intake and Edelbrock 600 CFM carb.
Had the original radiator flushed and cleaned. Running 160 dergree thermostat . Only reads 160 as it passes by !!
Will climb to 230 at a stoplight if it's 85 or more degrees out.
Would full vacuum or ported vac give lower temps at idle. I'm running around 10 degrees BTDC on timing. Stat opens up. Top hose is hot.
Spinning the fan with the engine off,the blade slows quickly. (thermo clutch seems OK.)
Water pump hasn't been changed. Maybe HI-output style?

Thanks for input

L79vette

Did you have the radiator flow tested? If it is the original, it may have scale build-up in the tubes. Mine tested fine, so it went back in after the engine rebuild. Amazing really that an aluminum rad can hold up to nearly 40 years of use. Previous owners must have been conscientious about coolant maintenance.

Full vacuum for vac advance is best for idle temps.

You shouldn't really be able to spin the fan when cold. I mean, it should not move much at all after you quit pushing the blade.

C2BOB

Are you running water (with water wetter)? If you're running coolant try water. And verify that the fans actually running correctly. Personally I pitched the stock fan onto a shelf 25 years ago for the same reason (first 350) from my 67 and haven't regretted it for a moment.

vettes1st

First thing to do is verify the actual temperature with a good IR gun. If you buy a radiator get a good one, DeWitt's.

61iwon

If i was you I would check on the Dewitt radiator before I buy another. The one I have dropped the temperature and took care of my problem in the '61.

Talk to Tom Dewitt. www.dewitts.com

ghostrider20

Dewitt's seems to be the only option to the midyear radiator replacement.

The stock type radiator, to my knowledge cannot be rebuilt.

For the size of radiator you need to retain the stock shroud etc, and provide the surface area required to cool you motor, you will need an aluminum stack plate radiator, like the stock unit.

Water wetter is snake oil. And if you run pure water, it will corrode the block and radiator quickly.

Spend the money on a Dewitt's radiator, with the stock shroud, and a qualified fan clutch. Run a 180* thermostat. Use a 50-50 mix of antifreeze.

With this combo, you can forget that you even have a temp gauge in the car.

Secondly, get your ignition maped out. USE FULL VACUUM for the vacuum module, and check to make sure all advance is in by at least 2"-3" Hg below your normal idle vacuum.

What motor do you have?

Mark

shft22

Big Time !!!!!!!!!!!!!!!!!!!

Cruiser62

I had the same symptoms; bought an IR temp gun and found that while the temp did go up in traffic the gauge was wrong and it only went from 180 to 200, which is pretty normal. Let us know what you find and the actions you take. Good luck.

MasterDave

Actually Bill, temps rising at idle after a run down the road is normal. If it doesn't puke water it's probably ok but I would check it with an IR gun for sure. I installed the B-Cool radiator in mine to replace an old nasty radiator and it made a world of difference in cooling. The temp will still rise at a stoplight after a freeway run or whatever though (normal condition) to about 200 sometimes. I am a little **** about it so I installed a puller electric aux fan. It is switched at the dash so I can turn it on at idle whenever I want. It fits great inside the fan shroud and I still have the pully fan installed. I rarely use it, the alum B-Cool handles it fine. See sig for engine info...

SWCDuke

Most "flow tests" are meaningless. The guy at the radiator shop puts water in one end and if it comes out the other, it "passes".

As deposits build up in the tubes (from the use of high-silicate IAT antifreezes over the years) the heat transfer efficiency of the radiator is reduced and eventually reaches the point where cooling is insufficient - usually at highway cruise speed.

Idle heating issues are usually caused by ignition map or fan issues, and these should always be checked first regardless of the overheating conditions.

If everything else checks out and the radiator becomes the prime suspect, the best replacement by far is the OE reproduction from DeWitts. Nothing else that fits without modifications equals the original design radiator in terms of heat transfer per unit of frontal area.

Also, use slow silicate HOAT antifreeze like Zerex G-05 as it will not build up tube deposits as rapidly as the old green antifreeze. High silicate antifreezes of yore provided good corrosion protection, but precipitated out deposits in the tubes, so the typical failure mode is degradation of heat transfer rate, not leaks.

A typical copper core radiator can often be repaired by unsoldering the tanks and "rodding out" the tubes to remove the deposits, but the furnace brazed construction of the aluminum radiator precludes disassembly, repair, and reassembly in the field.

Duke

65 Hardnoks

Just put an electric fan on and your problems are gone.
If I had the bucks to buy a 100 point Vette, I'd put an electric fan on it too. There is no substitute.

Just my $.02.

Jerry Chabino

I had the same problem with my 427 67. It would run cool as long as I was going down the road at 50. Come to an idle and it would heat up very quickly.


Two things

1. Must have original shroud in place.

2. Get a balanced thermostat. IMO 160 is too low. I run a 185 with no problems.

0Tom@Dewitt

The only problem, this advice was only worth $.01

Good advice can be found in either ghostriders20 and SWC posts.

Not one person asked what radiator was in there now. I find a ton of people "Assume" the radiator they have is original, only to find out it is actually a copper/brass replacement. What if it was downgraded to a copper/brass replacement over the years? A 30% reduction in cooling capacity can have an affect on things.

Downgrade the radiator and upgrade the engine and see what happens.

65 Hardnoks

How can getting rid of all one's cooling problems be only worth $.01? An electric fan is much cheaper than buying a NOS aluminum radiator.

That's all I was trying to say.

65air_coupe

Tom's point is very valid, I had what I thought was a stock radiator and was considering electric fans too. Turned out mine wasn't stock and put in one of his and no further problems.

And electric fans can't increase the cooling capacity of a radiator.

rgs

We have empherical evidence that at least in our 240Z SCCA Improved Touring race car, it dropped our temp 7 - 10 degrees.

C2BOB

I've run water for years with no issues but maybe that's because everything's corroded out! That must be the reason I can run the water pump and fan 30% underdriven with no issue. Recognize however nothing, nothing works as good as water. Coolant doesn't wet well so the heat transfer is poor. If you don't have headers and are considering them this may be the time to do the change. Getting rid of those cast iron heatsinks attached to your heads will significantly lower the running temps (and improve power, fuel economy etc). BTW I use one of those cheap six bladed black plastic flex-o-lite fans which runs quietly, obviously cools just fine and is so light you can feel the change in throttle response from the lowered flywheel effect when you put one in.

ghostrider20

How will headers control coolant temp?

Headers, with there larger surface area, and thinner wall, will ADD to under hood temps, and not just a little.

This will act as a heat sink, but for the most part, that will entail just the hot exhaust gasses. Which will be passed on to the engine compartment. The free-air heat rejection properties of the engine itself will be reduced by this. Unless you have a cool air induction system, the increased air temp, will decrease performance.

I guess I just want a car that I can turn the key and go, and not have to worry about the car failing me.

Electric fans don't run for free, if it is a good fan, stand by the alternator and listen to it groan when you turn the fan on. Then go watch the RPM fall 100 points. Moving air takes energy, be it from direct mechanical work, or an added electrical step in the equation.

Mark

C2BOB

The cooler engine temps with headers are an observed condition. Just one of those things that comes with experience.

0Tom@Dewitt

Actually electric fans can and will increase the cooling capacity. It's just that in most cases, it shouldn't be required on cars that didn't come with them.

Editoral: (not aimed at you 65air_coupe)

I find discussing cooling issues on the forum becoming harder and harder to do. Maybe it's not getting harder, I'm just loosing my patience. In order to offer anyone advise, I need ask a lot of questions and verify a lot of items before I recommend anything.

It seems half the people on the forum recommned something without establishing the basis for the trouble. Some will endorse a product or a method soley because that's what they did or bought. It makes them feel better it think.

I could answer just about every cooling question with both a yes and no, depending on how vague the question is. It happens all the time at swap meets where multiple customers are firing questions left and right. Two guys will ask "will your Direct Fit model cool better than the original"? Well our Direct Fit is an upgrade for the C1 and it's a downgrade for the C2 SB. So I answer Yes to guy#1 and No to guy #2 and both walk away confused because we didn't discuss it in great enough detail. Which is exactly what happens here. You can't get to the real bottom of something with half the story and multiple misleading suggestions pouring in.

Now that's not to say there isn't valuable input here. If SWCduke says it, you can take that to the bank, dis-regard all the other bs and do what he says. You will never go wrong. The problem is, this good advise typically is weighed equal (or less) to another post that's full of it.

Cooling seems to be quite controversal. That's because we have hundreds of opinions and theories on this or that. If you are one of those that believe you know more than GM, think again. GM has much better engineers and they spent hundreds of thousands of dollars researching and testing. If straight water, for example, was a good idea then why hasn't one car company ever supplied it that way? Yes, water will cool better than a 50/50 mix but shouldn't be necessary, unless of course you are on a track that doesn't allow coolant. See... a yes and no answer again. Drilling thermostats is quite popular but I fail to see the logic.

The value of Corvettes has never been higher and why people spend tens of thousands on restorations and 5-6k on a engine and then go on a budget on the cooling system makes no sense to me. That my rant for the month