I think one thing that is missing in this thread is, what are the actual temperatures you consider overheating versus the temperatures you see at idle?

 

That is not a problem. I am both to cheap and to poor to do it any other way.

Thanks
Zorro

 

I am going by the temp gauge. When I start driving to temp comes up normal, If I stay off the freeway the temp comes up to the 180 mark on the gauge and stops as the thermostat opens. If I am in traffic the temp will move up to 185 and my fan comes on (yes I know it's working) the temp will then drop back down to 180. If I get on the freeway it will heat up to 180 and will stay there for a couple miles, then it will creep up, it will hit 185 and my fan comes on but has little or no affect, and temp moves past 220 and up into the red.

Thanks
Zorro

 

Is the fan pushing air in the right direction

 

Ok, so here is what I did today. I borrowed a radiator pressure tester an hooked it up. The first time the pressure fell right off, so I pumped it up again and looked for leaks. I found a cut in the upper hose under a clamp, shortened it and checked the pressure again, it held 16 pounds for an hour so I took it out on the freeway it went twice as far as before to start overheating, I got off the freeway and unlike yesterday it cooled off in traffic. I took it home and I did not hold pressure as well as it had. I found a leak under my throttlebody. I rerouted the heater hoses to bypass the throttlebody, same thing on freeway. The pressure takes about an hour to drop 2 pounds, I don't know at this point if it is the car or the pressure tester itself losing the pressure. Now I have a laser temp gun and next will see if I can determine if I have flow. I will also replace the thermostat, just because it is easy and cheap.

Thanks for all the help.
Zorro

 

The system might need to be burped. If there's an air pocket it can create a situation where heat transfer is not occurring. Make sure all the air is out of the system.

Another possibility...what kind of coolant are you running...ethylene glycol or Dex-Cool? If you have Dex-Cool it is not compatible with any glycol based coolant and will form a cloudy mess and clogs within the system. It's particularly bad with aluminum engines as overheating can cause blown head gaskets.

Also...if you have TPI...is it installed on the original 350 or a more recent TPI engine? Some later engines were reverse flow.

 

I am running an L31R (LINK) crate motor, it is designed for 1996-2000 full size trucks. I have the original V-belt system from my 79 C3 on it running a 79 replacement water pump. The pump is turning the same direction as the crank. Would anyone know if this setup is correct?

Thanks
Zorro

 

Don't you just hate it when you read a thread and it just ends. You have know idea if the problem was ever solved. I was very much tempted to let this one die rather than admit what it turned out to be. Kind like "it's better to keep your mouth shut and let people just think you are an idiot, rather than talking and removing all doubt." But that won't help the next guy who has this problem, and went to the effort to read this thread.
Today I was under the car looking for the problem again and decided to start at the front and work my way back. I turned on my electric fan to make sure it was working and sure enough it came on and I could feel the air moving under the car. The blades spin so fast you cant see them, but the air volume just did not seen like enough. So I took a paper towel and held it up to the fan to see how well the fan was working. The paper towel flew out of my hand and was glued to the fan cage. The fan has been working as a pusher instead of a puller, so when I drive around town it keeps the radiator cool no problem, but when I get on the freeway it is working against the air stream canceling it out. I got out the fan instructions and all my wiring was correct. Then I found a note saying that if the fan runs backwards swap the hot and ground wires. guess what, this thread has a happy ending!

Thank you all, for the help.
Zorro.

 

Diehrd had it correct!!!!!

 

Thats cause I am always looking at stuff backwards ....

 

Going to throw this out there because my 1977 was over heating once I got up to 70 MPH out on the highway. It would go up to 210 at between 70 and 80 MPH for an extended 5 to 10 miles at this speed. then cool down again once I was back on surface streets or backed off to 60 MPH. Not saying your problem is the same as mine but here are the steps I took to resolve it.

I did have a few problems but the main was the Transmission Filter was clogged and the tranny fluid was burnt. My tranny would start to slip after it got hot. So I dropped the pan and installed a THM 350 After Market pan with a drain plug when I replaced my Transmission Filter. Since the Fluid was also burnt I knew I had to change it at least twice to refresh the fluid in the tranny. The THM350 Tranny holds 12 quarts of fluid and draining it twice will refresh the fluid.

Now I went over kill on the second drain and installed a Transmission Cooler in the system along with a 160 High Flow Dual Stage Thermostat after flushing the radiator with a chemical flush to remove most of the hard TAP water deposits scaling. I refilled my radiator with a 50/50 mix of Distilled water and Anti Freeze than also used a Water Wetter to lube the system. Water Wetter like this add lube the water pump and system.

http://www.autozone.com/autozone/acc...ntifier=486218

After this my temps never exceeded 190 on the temp gauge even at sustained speed of 80 MPH on the HWY. This week I ordered a new 4 Core Radiator from Summit Racing to finish my cooling system project because the original 3 core has so much scaling in it the chemical flush did not remove it all. While it does not over heat any more I did need a new radiator to finish the project.

 

Being old school and have owned many Chevy and Fords over the years in my early days I consider anything over 200 Degrees on these older engines as running hot. Newer engines like to run hot and with fuel injections systems they have improved fuel economy by running engines at between 190 and 210 degrees. Does not work well on older engines and as some of know Aluminum intakes like the aftermarkets will keep the fuel cool before it is burned. Cast iron gets to hot and holds heat than reduces the HP on the engines.


I have always installed high flow thermostats at either 160 or 180 degrees in these older engines to keep the cooler. Thing about carbureted engines of this era is you want to keep the intake manifold as cool as you can to improve the Horse Power. Colder fuel going into the engine means a better burn. Keep the top end of the engine cool and the fuel will come in colder which is also why they make cold air intakes, RAM Air and Cowl induction systems to keep the fuel cold into the engine.

 

Backwards or not, it was your post that made me double check the fan rotation.

Zorro

 

Your welcome ! I do like when you post and post to help people and u actually do help some out .

 

Nothing to be embarrassed about

It's easy to get the fan spinning wrong.
I was worried when I first started reading your solution that you were going to say it was out of water

Glad it all fixed and happy again!

 

My 78 is doing the same thing. I've been told that there is supposed to be some kind of air director between the air dam and radiator. Mine has none. I'm trying to find out more about that. Have you ever heard anything in that line?

 

I have one of these on order myself from Corvette America.
#37749 |1979-1979| Spoiler Extension.

Zorro.