Dumb Question

[ranger danger]

Will headers help to reduce operating temp of the motor? My 454 sometimes gets a bit hot (225*) in stop and go traffic on 100 degree days. Id like to get control over that. I will be towing a 6000lb travel trailer in the mountains of northern California with it starting this summer.

[68gmsee]

In the few cars I've had that I put headers on here in Texas where the temp can climb up to 110 in the summer, I don't remember it affecting the engine temp. If the the fan, water pump, hoses radiator cap and the engine are in good condition I would spend the money on a new high efficiency radiator rather than the headers. However, if you have the extra money try both. Wouldn't hurt.

[nonstop]

Agreed with the aluminum rad. I have headers and the thing still heats up sometimes. Another issue is headers can increase underhood temps, negating benefits.

[GASoline71]

Throw money at the cooling system instead of headers. If you're still using the stock 40 year old original radiator, it might need a new core or need to be rodded out. Or like mentioned above replace it with a stock replacement or an aluminum. Use a shroud if you don't have one.

Gary

[ranger danger]

I have a shroud. The radiator was rodded out about 6 months ago. The guy said it was about 30% blocked before the repair. Factory original copper radiator. Carb is a quadrajet built by SMI. Vacuum gauge shows a rock steady needle at about 21" vacuum. Intake is Edlebrock performer. MSD pro billet dizzy. Timing is set static at about 14*, all in at about 28-30* around 2600rpm.

['63GENIII]

If the radiator is big (4 core) and clean, Id start looking at airflow and water circulation. My 396 used to get pretty hot while towing until I got rid of the flex fan. Installed a 19" or 21" (can't remember which) 7 blade steel fan, HD fan clutch and a shroud with the fan about half way into the shroud. Hottest I recall it getting was 205 while sitting on the Causeway near Sac on a 116 deg day and towing everything back from Lake Collins.

As far as the headers, I ran some on my '76 CC 4x4 Dually some years back. Did nothing for the engine temp. It DID make the underhood temps unbelievably hot though. I ended up cutting a few vents into the radiator core support to let more air in. That helped.

[storm9c1]

Not a dumb question. But headers won't help.

Things that WILL help:
- 7-blade HD fan with a new clutch. If you still have a stock 7-blade fan, good! Check or replace the clutch.
- Flush out the engine coolant really well, including the block.
- Tune the QJ one step richer -- this has REALLY helped with Eddy carbs on my big blocks.
- Check for vacuum leaks which will make an engine run lean.
- Advance timing a few more degrees, but don't let it ping.
- New 4-row radiator. It if was 30% blocked, rodding is only a temporary fix. Make sure fins are straight and not blocked.
- Make sure the shroud is good and fan blades are 3/4 recessed (blades covered) in it front to back.

[68gmsee]

From what I have read the aluminum radiators are really more efficient than the copper core we had in these trucks. A search on the internet will show they are better. If you are concerned about overheating and not about keeping the truck absolutely stock the aluminum one is the way to go.

Be sure and eliminate any other probable causes of overheating first as mentioned above.

[A1971Blazer]

In past experience........those 454s tend to run hot a little hot....I had one years ago that wanted to overheat.....I threw money at the radiator to no avail....finally ran across some info (this was pre-google era) about putting a slight restriction in the cooling line where it went into the top of the radiator..
I made a do-nut type washer with a small shoulder machined on it to secure it right at the hose connection.

I can't remember the exact size.....and IIRC I made several before I got it right.............but what happened was, the thermostat opened at the same temp.......but the restrictor slowed the coolant flow enough to allow it to absorb a little more heat as it flowed thru the motor.....it worked......dropped the coolant temp about 20º.......still ran at 205º

If you're running an auto tranny......and you probably already have one........but you for sure need a heavy duty auxillary tranny cooler......that trans will get hot.......especially when towing.

[franken]

People are all excited about aluminum radiators but aluminum conducts heat less well than brass and copper. The tubes in AL rads are also larger, which in my tiny mind means less coolant in contact w/ the metal and therefore less cooling.

This is much like the mini-starter trend. Car makers are under pressure from the government to reduce emissions and increase mileage. They're also always trying to spend less. More plastic, and other light materials may reduce the bloated weight of a vehicle, but that doesn't make the parts more efficient or better.

I'd use an original style radiator, shroud and clutch fan with a stock temp thermostat, and work from there..

[ranger danger]

It does have a 7 blade OE fan and the fan clutch is new (6 months). Radiator is 4 core. Shroud and blade depth are good. The coolant was flushed out at the same time the radiator was rodded and I added one bottle of water wetter to it. I've sprayed the intake manifold, carb and brake booster fitting with carb cleaner looking for vacuum leaks and found none. Also replaced tranny vacuum lines and checked for leaks there. I am not Qualified to mess with the carb so Ill keep trying to find someone local that knows there stuff, that has been my biggest challenge!! I would really like to find a local guy who knows his stuff on these motors!

[68gmsee]

Pros and cons on either copper or aluminum. Cost being one. Copper is at a premium these days. The best thing for a person to do is to do their own research and ask radiator shops to decide which way to go. If I was going to go for the stock look I'd go with a high efficiency copper radiator but if it was a daily driver or work truck, I would not hesitate to go with aluminum.

http://www.cgj.com/2013/07/16/alumin...inal-thoughts/

http://www.caparadiator.com/aluminumvscopper.html

[TJ's Chevy]

Duramax diesel radiator and dual electric fans. On a 100 degree day kept my 496 below 220 and it had headers. You'll want a shroud as well.

[nonstop]

Just curious - what thermostat are you running? Mine will hit 225 at times with a 195 thermostat (too hot), but seems pretty happy with a 180, where it will run 195 to 210 - verified with infrared thermometer. I have tried a few different 195 and 180 degree thermostats, giving me the same results. Just something to keep in mind or try.

[ranger danger]

Originally Posted by nonstop

Just curious - what thermostat are you running? Mine will hit 225 at times with a 195 thermostat (too hot), but seems pretty happy with a 180, where it will run 195 to 210 - verified with infrared thermometer. I have tried a few different 195 and 180 degree thermostats, giving me the same results. Just something to keep in mind or try.

It's got a 180* thermostat in it. It will run at 170-175* when the weather is down below 65* but as it gets hotter (above 78-80*) it will run at 185-195*. Then when the temps get over 85-90* It runs a steady 195-200* unless I'm in stop and go or uphill or with a load. Then it goes over 200* and as high as 225*. All of this is verified with an infrared thermometer.

[storm9c1]

OK, so if it gets hot in stop and go traffic plus pulling hills, that doesn't sound like carb jetting to me. Usually a carb-lean overheat condition will only be seen at speeds above 45MPH both pulling or cruising. And if your cooling system is up to the task, temps will fall back down when your speed is under 25MPH. But you are saying temps also rise at lower speeds, right?

I'm leaning toward cooling system issues now. If your rad was 30% clogged, I hope your cooling passages in the block aren't also clogged.

[ranger danger]

Originally Posted by storm9c1

OK, so if it gets hot in stop and go traffic plus pulling hills, that doesn't sound like carb jetting to me. Usually a carb-lean overheat condition will only be seen at speeds above 45MPH both pulling or cruising. And if your cooling system is up to the task, temps will fall back down when your speed is under 25MPH. But you are saying temps also rise at lower speeds, right?

I'm leaning toward cooling system issues now. If your rad was 30% clogged, I hope your cooling passages in the block aren't also clogged.

The engine is a crate motor with about 15k miles on it. The radiator is OE I believe. I am leaning towards a radiator as well. What are some of the best sources for Aluminum radiators? Would it be best to get one with or without electric fans? I'm looking for simplicity and function.

[storm9c1]

If you have a good 7-blade OEM fan with a good heavy-duty or severe-duty thermal clutch, and a good shroud, then you shouldn't need electric fans. Keep it simple.