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I am having overheating problems I just cannot seam to fix, and I'm at a total loss on what to do next. When I planned this project I had a 3 core radiator made. The shop said a 19x22, 2 core radiator would be enough but to be sure I wanted a 3 core. Then I added a bigger mechanical fan, and another bigger fan with more cfm. Finally I install an electric fan to push air into the radiator, it pushes 2700 cfm with a mechanical fan helping. The truck will run at 190 degrees in stop and go traffic with everything working normal, then when the tempergauge start to move up there is no stopping it. It will run normal for 15 to 20 minutes, then it starts to overheat. I've changed thermostats. The water pump along with everything else on this truck is new. If any of you have any ideas to help me, I would be very greatfull. What fun is it to have a v8 Luv if it can't leave the garage? Thanks Rick

You have a PM...

Can you shoot some pictures of your setup so I can have a look?

I used to have the same problem in my old 74 chevy stepside.

The culprit was a couple of old hoses that were ballooning when the engine warmed up plus a small piece of foil from the seal from an antifreeze bottle that the previous owner accidently dropped into the radiator. It would settle down into the system when it was cold, and as soon as the engine warmed up and the thermostat opened, it would lodge in it and restrict the flow of the coolant just enough to cause it to overheat.

I was trying everthing for days with no success, but once I replaced the old hoses and flushed the block and radiator, everthing was fine.

Good luck...this kinda stuff can drive you crazy.

Ben I sent you 4 pictures to your email addy. Hope you can help me out.
Thanks Rick

Make sure the ignition timing is correct. Also, my Pontiac 455 ran hot all the time before I realized it was running lean. I went a few sizes up on the jets and now it's fine!

Possible cracked head maybe.

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Too much to do and not enough time or money!
Courage is the other side of fear!
Pain is the weakness leaving the body!

Thats what I am starting to think is wrong also. Pulled all the spark plugs. Seven of them looked the same, one was black and shooty looking. There are no air bubbles in the radiator, so it must be coming out the exhaust. I guess I will have to pull the heads and have them pressure tested. Thanks for everyones reply. I will check out all the suggestions first, then go from there.

Normally I have found a cracked head or blown gasket to have a rusty looking plug after it has been run. I have seen most run normal and only heat up on idle. have you done a compression check ye ton the cylinders.

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Too much to do and not enough time or money!
Courage is the other side of fear!
Pain is the weakness leaving the body!

I had this problem for a while when I got mine together. You never said, do you already have an aluminum radiator?

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Money can't buy happiness, but it can buy horsepower...and that's kind of the same thing...

No I have not run a compression check yet. And no I do not have an aluminun radiator. After pulling the plugs, thats all I've done. Hopefully next weekend I will get busy and find my problems. Thanks everyone for all the replys. Rick

Suggestion -Do a cooling system pressure check first then check your timing curve to be sure it is advancing enough.Also you may want to go to an alum. rad. the same size.Another quik test is to pull the t-stat and run it, it should run cold this way.Your t-stat could be sticking and only opening part way.More if needed

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1978 pro street step/side 455Buick, 4sp,4.11s, 31/18.5s

Got the pictures. Very clean install, BTW.

Are you running a thermostat? What temp is it if you are? You can pull the thermostat as a test, but I wouldn't leave it out. It's easier to tune a motor for max performance on the street if it runs at a constant temperature. For the most power, you'll want the lowest thermostat you can get.

What size is the motor? 350? 400?

The radiator looks big enough. You could benefit from an nice 2-core aluminum but you shouldn't need it with a 350.

I like your mechanical fan selection, but you should consider a shroud of some sort. I had the same fan on mine and a simple shroud made from a 4" x .032" piece of aluminum made a difference. Your fan is a little far from the radiator too, which wouldn't be an issue if you had a shroud.

You'll want like 1" of clearance between the shroud and the fan. So if that's a 19" fan like I had, make a 21-22" ring out of a sheet of aluminum or tin, deep enough to attach to the radiator and extend past the majority of the fan blades. Yours is kinda far, you might need like 5" deep or more. At the radiator, attach the shroud with the same hardware you use for an electric fan with some small L-brackets.

If you running a 350, your almost there. Your still gonna need the electric for sitting still in traffic. Even with a shroud, the mechanical will barely keep up at idle.

But above idle, that mechanical is really gonna cool things off with a shroud. I think it'll be enough to get it under control.

If your running a 400, your probably gonna have to go with the aluminum style.

You should also consider using a separate trans cooler. I've had mine mounted low, under the front of the truck between the bumper and the frame, and then later under the bed on the pass side. Both locations worked OK. Under the bed, you'll need another fan for it. I kinda liked under the front of the truck better because I didn't need a fan. It worked fine until my ex-wife used the truck for curb surfing and wood fench relocation.

ive been having the same problem with my luv, with the stock motor. took the thermo out and it is still running hot. flushed the radiator and same thing. sorry to hijack your thread but i had to chyme in as well.

I tried SEVERAL different things an mine and it would not stay cool. I tried the radiator with the tanks on the top and bottom and the one with the tanks on the sides. Tried different size fans and shrouds with no luck. The aluminum radiator made ALL the difference, you can also try drilling a couple small holes in the thermostat too.

This is only if you dont have mechanical problems, I would make sure of that first.

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Money can't buy happiness, but it can buy horsepower...and that's kind of the same thing...

Thanks Ben for the imput. Summit has a fan shroud like you are talking about for $32.00 I am thinking about buying it. I have tried running the motor with different size t-stats, and without. But it would still overheat. I have bought a new style thermostat, that when it reaches 180 degrees it locks it in the open position. When the motor cools down it allows the thermostat to close. I am running a 350 also with a mild build up. I think the tyranny cooler is also a good idea I need to follow up on that. Also the timing on the motor is right on. TJ said I need to check my timing curve. I have a stock Chevy distributor, that I put a Crane Fireball electronic ignition in. I'm afraid that is over my head. I need to do some research on the web, to learn about that. But I will this week. Thanks for the complement Ben, it is much appreciated. Thanks all,I sure like being on the site with such nice people. Rick

Cool, let us know how it goes.

Timing curve is the initial to full adv. at a set rpm. Lts say you want 12* initial adv.(most chevs should start here) and you want your total in by 2800-3000 rpm's a total of 36*-38*.The curve part is how the timing will adv. as the motor revs to the desired rpm. Most of the after market adv kits are not good curve kits as they use to light of weights but the do have the springs to make your dist. near perfect. Are you confused yet.Hear is a start get an adjustable timing light and check your adv. without the vac.,check at idle then slowly raise the rpm's until the timing has advanced all the way and check the rpm's that this is at. I don't like vac adv on a mild to wild motor as the timing gets to bouncing around to much although there are cures for this it's better to leave well enough alone.

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1978 pro street step/side 455Buick, 4sp,4.11s, 31/18.5s

wouldn't hurt to check your balancer against tdc , and don't forget to trim your shroud or space the fan till half of the fan is exposed from the shroud.

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72 luv v-8 owned since 16!
240" rear engine dragster
traded the circle track cars for a blown 496 chevy
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29 dodge 4 dr sedan (project)
84 ranger 2wd "tuff truck" with 350 sbc