Cant make it run cool

[Radarjim]

...Ok, sort of new here so please be patient with my ignorance. I have a 1962 Impala bubble top. It has an almost stock 409 in it. it has a very very mild comp cam and the rest of the engine is bone original. it has the facorty aluminum"Winters intake". it hs been bored .030 over and uses "Ross" 9.1.1 Pistons. Fuel delivery is Holley Terminator X Stealth EFI. I have Dougs Stainless steel "Long Tube" Headers. The transmission is a prepared 4L60 shifted by the computer. The transmission is cooled by "Stand Alone", Derale fan assisted trans cooler, remotely fitted away from the radiator.
I have a 4 row "BE COOL" radiator ( vertical flow ) currently and have tried a very expensive U.S. Radiator, It is the "Optima' 4 row 3-way flow". My problem is that I can not get the engine to run cool enough that I feel confident in traffic. ( Yuma az.) summer temperatures average around 112. Sitting at a stop light in the afternoon with the A/C on is not an option, since it will get up to the 230's.
I have tried 3 radiators of different configurations with three different shrouds, to include the facory "Barrell type". I have an aluminum "High Flow" water pump. I run the engine at 12 degrees static timing. The computer maintains a 3.98-4.0 AFR ( Air Flow Ratio).
I have installed a 16" 3000 CFM electric fan. I have tried using a very agressive Motorhome 7 blade medal fan along with the electric fan and still it wont cool. I have installed two different manufactures Thermosats. 180, 190 and 160 to no availe. The engine has a total of 338 miles on it since overhauled and installed.
As a point of interest, using a "Thermal gun", the inlet temperature to the radiators is 190 and the outlet water temperature to the water pump is 184. When running the temperature up to 225 out of the engine, the temperature differental is 214.....Ugggh
While driving the car down the highway it will constantly climb slightly to the point that I have to turn off the A/C, and what ever the temperature is at that time it will not cool down, in fact it might even slightly increase a degree or two.
I have run out of ideas and pray that someone out there can enlighten me...Thank you for reading this.

Jim

 

[1958 delivery]

Operating temp of 200-210 is not out of the question on a hot day

 

[our1962]

Did you burp the cooling system?

 

[Jeffrey Osstyn]

Radiator capacity is key, I have cut my radiator support so I can fit a larger truck radiator in. Dual electric fans with a good shroud, I like pullers not pushers if possible. Also, the radiator fin construction has some effect. Proper coolant flow is also a piece of the puzzle. Not too fast, or too slow.
Not familiar with your 'Air Flow Ratio #'s?' Should that be Air Fuel Ratio? If so those #s are way off.

 

[blkblk63ss]

According to info I searched the temps across radiator inlet to outlet should be 20 degrees difference. You only have 6. Are you moving coolant to fast through radiator. You mentioned a high flow water pump .Also have you tried a two core aluminum radiator??

 

[Robert Jacobson]

I will tell you a story that might help. When coming back from Viet Nam in 1972, I bought my first Corvette, a 1968 roadster with a 390HP 427. I was going thru the same problem you seem to be having. My father was a purchasing agent at AC Spark Plug therefore having connections at GM. He put me in touch with an engineer who was instrumental with designing the 1968 Corvette. He told me that in testing the vehicle things were fine but as soon as a front license plate was installed the engine temp rose 30 degrees. The license plate mounted in the center between the two outer grilles. I am in Michigan where at that time a front license plate was required. This part of the story probably does not pertain to you, just thought I would mention it. After further conversation I mentioned that I was using a 160 temp thermostat. When I purchased the car, there was no thermostat at all in it. The engineer told me that was where my problem was. I first installed a 160 in it thinking it would run cooler with that. He told me that normally the 427 would run hotter than that therefore the thermostat would open and stay open once the engine got up to normal running temp. He told me to install a 195 thermostat in the car so it would not stay open all the time. He said that without the thermostat closing at all the coolant would never be in the radiator long enough to cool down to be effective and address the problem. I did this, the temp never got above 210 after that which he said was perfectly normal. He told me not to worry about the temp unless it reached 235. It never did. Maybe this won't help but I thought it was worth mentioning. Good luck.

 

[R63ss]

That’s why I pulled the plate on my 67 tri power runs 165-180 now

 

[425/409ER]

Run the engine up to temp and keep the cap off, then look to see how fast the coolant is running though the radiator. I had a BBC like that and I tried everything to cool it down and nothing helped, radiators, dual fans and a bunch of crap, nothing worked. One day I remembered that my old 396 in the Nova I owned always ran at 170-180° and this BBC ran 200-210° What I found was the water pump that was in the car had a 9 blade impeller, the Nova water pump (which I still had at the time) had a 7 blade impeller. I put the Nova water pump on and my cooling issues were solved. Seem if you run the coolant too fast through the radiator, it never gets a chance to cool off in there.

 

[63impaloligist]

Sometimes you'll hear that it's not recommended to use an electric fan with 3 or 4 row radiators. I tend to use the Ford Taurus electric fan, the Dorman replacement. It's 2 speed but I only use the high speed on the Chevys. I did use both on the Black Cutlass only because it was set up for 2 speed Buick GN stock fan.

 

[Jeffrey Osstyn]

More crap to consider. Pure water transfers heat the best. Under the pressure of the radiator cap the boiling point raises above 212 degrees at sea level. Adding antifreeze will raise the boil over temp even higher but degrades the heat transfer of pure water. I run pure water in the summer with a bottle of anti-corrosion added.
More on the water flow issue. Years ago, you could buy round discs with different size holes in them that you installed in the upper radiator hoses (flathead) to slow the flow down. If you look at a modern radiator you can see that the upper hose inlet is smaller than the lower hose outlet, for just this reason. If you lower than fluid level in the radiator so you can see the ends of the coolant tubes through the cap. With the engine running, you should be able to see how much flow is occurring in the radiator. Look at how the coolant comes out of the end of the tube, it should just 'fall over' after exiting, not come out with any straight-line force. Water pump pulley ratios will affect this.
Do not discount any stock OEM cooling systems setup. They spend a lot of money testing to make sure your car will not overheat. Study how they do it and try to incorporate some of that free engineering.

 

[62_Conv_2-4s]

It's possible the engine was assembled with very tight tolerances. It may take thousands of miles to loosen up. Very tight tolerances will cause more friction adding to the over heating problem. Enjoy the car and drive it often, see what happens.

 

[Jerry B]

Agree with Osstyn. Had the heating problem with my rebuilt 409 even after putting 1000 miles on. Ran 210 on road and 220-230 in traffic on a 100+ day. Tried a lot of things. Two things helped the most was distilled water, 15-20% antifreeze and Water Wetter. And changing from 10-40 to 10-30 oil. Rarely got over 200 after that.

 

[Don Jacks]

What is your total timing at idle in gear?Are you using computer controlled timing or not? Low timing will cause these overheating issues as well.

 

[Z-animul]

This thread has been very helpful and has me wondering if I'm just being to paranoid. My '58 has a 348 and turbo 350 with what appears to be a stock radiator, I bought it built and know precious little about the engine's makeup. That said, I find that it tends to start overheating (at least to my thinking) on the highways at speed 65-70. I did a short run on a local 4 lane, about 3 miles, and while on side roads it stays around 190-200, but about 2 miles into the highway run the temp started to climb. I got nervous when it hit 210 and seemed to be climbing. I got off at the first exit and once we were on the side roads running 45-55 it started to cool back down. No idea if the temp gauge is accurate so that is a concern as well, again I bought someone else's project that was about 95% complete.

 

[lennyjay]

Someone mentioned the thermostat and to install a 195. That maybe a quick fix and I am thinking to put one in my 09 (has a 180 now). I am in AZ also, and after a short ride to town and back temps rise to 200 and climbing. The fenders are so hot you could cook eggs on them. Yes, I have all the stuff talked about in the responses its just the outside air is so hot the radiator can't remove the heat. Looking forward to a fix....if there is one.

 

[Don Jacks]

Do you have a tach in the car? If so,note the rpm at the speed where the heat climbs.TakE your timing light .with vac,. advance hooked up and check your timing at that rpm. If it's less than 45,advance it and see if that helps.

 

[lennyjay]

Yes, good point. I checked it at idle (12deg) and reved to 3000 to see if advance was working, it was. Will try your method next. I do have a gas analyzer (old unit) that I can check if we are running lean, also can do a plug check after I come back from a ride to check color. Once checked if lean I can step up 2-sizes on the primaries (back carb) to see if that helps.

 

[Jeffrey Osstyn]

This thread has been very helpful and has me wondering if I'm just being to paranoid. My '58 has a 348 and turbo 350 with what appears to be a stock radiator, I bought it built and know precious little about the engine's makeup. That said, I find that it tends to start overheating (at least to my thinking) on the highways at speed 65-70. I did a short run on a local 4 lane, about 3 miles, and while on side roads it stays around 190-200, but about 2 miles into the highway run the temp started to climb. I got nervous when it hit 210 and seemed to be climbing. I got off at the first exit and once we were on the side roads running 45-55 it started to cool back down. No idea if the temp gauge is accurate so that is a concern as well, again I bought someone else's project that was about 95% complete.

With temps climbing at highway speed tells me you have airflow issues. At that speed my fan does not come on and just the airflow from moving cools mine just fine. Try to maximize the air going through the radiator by blocking off any openings that would let air get in the engine compartment without going through the radiator first, like around the radiator edges.

 

[61BUBBLE348]

a thing to remember, for every 1lb of pressure you raise the boiling temp of water by 3 degrees, I run 13lb radiator caps raising the boiling temp by 39 degrees or boiling point will be 251 degrees, Also use a recovery tank and associated radiator cap. In general with this setup, if you are not losing water you are OK. I second making sure there is no air in the system, any air will cause steam.

 

[Murphdog]

I think I heard that the wrong kind or too much paint can cause heat dissipation issues???
Jeff