Hot Rods SBC overheating...yes I've tried almost everything!

An engine is not overheating unless it boils over. If you put a 16 lb cap on , you have increased your boiling temp to 250 degrees... Also I have not seen anyone mention a Flo Kooler water pump. They do work. Just a comment to add to the discussion.

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In your first description you mentioned that the truck was in a wreck. Was it a front hit. I had a friend who was chasing much the same problem you described. I turned out that the water pump fins had been damaged from the impact. It was an original water pump. the vanes had corroded and with the impact they just broke off. At high way speeds the little nubs were able to move coolant but at idle no coolant moved. without cooling moving through the system, that would explain a lot of the symptoms your are describing.

Fair at highway speeds.
Gets hot at idle.
Radiator even temp across tanks, no coolant is moving.

 

So I've been tinkering with the panel today. I removed the flex fan and left the electric fan on it for idle just to see what difference it would make at highway speed.

It gets up to about 210-215 at idle and I can turn on the fan and it will prevent the temp from climbing any higher but will not lower the temp. I'm thinking maybe the fan is just too weak for this application.

I have noticed a decrease in temp by simply removing the fan that was incorrect.

I didn't get to drive it very much, only about 7 or 8 miles. I plan to take it out tomorrow and get some decent miles on it to see how well things have or have not actually improved.

I left the radiator cap off today and tried burping the system. I noticed a lot of air bubbles at first but after topping off the radiator and letting it idle for a few minutes the bubbles quit. While doing this, however, I noticed something was off. I am using a 160* thermostat because my first attempt to cool this thing was to change the 195* to a 160* (guys, feel free to comment your opinions on this.) My temp gauge showed around 175-180 before my coolant level dropped in the radiator. This leads to one of two things, I suppose. Either the gauge is off 15-20 degrees or the thermostat isn't functioning properly. Would you guys suspect the gauge? A faulty thermostat wouldn't open at all, would it?

On another note, would you guys recommend a larger, more powerful electric fan or ditching the electric fan completely in exchange for a mechanical reverse rotation one? Mind you, I have no room on the front for a pusher so it's either electric puller and no mechanical or mechanical and no electric at all.

Also, how can I insure the radiator is moving coolant to make sure I don't have a water pump problem like described above? Should I see the movement easily in the radiator or do I need to remove water neck to see this? The truck was hit in the rear so there was no front end damage. Both sides of the radiator are hot and both hoses are hot to touch.


Sorry for the bombardment of questions, but you guys sure know the answers and have lead me in a much better direction than I have been able to find on my own. I'm getting close to having this problem completely taken care. You guys are the best.


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How many cfm is that electric fan you have?

Do you have a meat thermometer? Put that in the filler neck into the water and see how it compares with gauge as the thermostat opens and closes.

What did the temp do while you were moving down the road?

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I don't know how many cfm this fan is. The only marking on it is 12v and 80w. It can hold a piece of newspaper against the outside of the radiator and that's all I know about it.

I will have to get a meat thermometer for comparison.

The temp cooled down to about 185-195 while driving which is actually an improvement from previous occasions. It is 85* and extremely humid in KY today.


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Get a good mechanical fan and shroud on it and you should be fine.

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Yes, i WOULD suspect the gauge because what do you expect for $14.50?

Why don't we just test the gauge?
http://www.madelectrical.com/workshop/water-temp-gauge.shtml

Even if the gauge checks out i still wouldn't use it because i guarantee it won't last because it's shit. Again, no disrespect to you or your equipment. But i've had gauges like that---they do not last very long.

 

Get the right heat range thermostat in there. 190 is good choice. While you're swapping it out,,, bolt the neck back on without the t stat and start the truck. You should see plenty of movement of the coolant. Here's where you decide to change the water pump if you wish.

The only way to check your guage is with another measureing device. An IR thermometer, a meat thermometer, another guage.

The only way to test a t stat is with a temp measure and observation of water flow to begin or put it in s pot of water on hot plate and measure temp while while watching it to open up.

Pusher fans are useless,
A good mechanical fan and shroud is the best. Use an electric puller only if there is no physically possible way to get a mechanical in there.

 

Look at post 69..... It is a mechanical gauge.

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Thanks again guys. I will be back on this tomorrow and will be taking your advice. I hope to drive it more tomorrow and put more miles on it to get a true test of any changes.

On a side note, any recommendations on a good temp gauge? I've been looking at Moon Eyes or Stewart Warner.


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As the coolant heats up, it expands. I've seen thermostats do just what you are seeing. Typically there's a 10-15 degree desperation as what you are seeing.

Go to a junkyard and get your self a ford Tarsus fan, they move alot of air. Lincoln mark 80 moves a ton of air (4,200 cfm)

 

Those 50's Dodge engine compartments need proper ventilation too, trapping all that hot air under the hood will still be a problem regardless of the fan configuration. On a 1950 Plymouth that originally had an inline 6, we had to trim the inner fenders a little to allow the hot air to escape to make room for the fresh air coming through the radiator. It's all about the airflow.

 

Back in the day, a friend GAVE me a 454 BBC, because he tried everything in the world to solve overheating problem. When I pulled the heads, I found a plastic bag stuffed into the block water jacket. Who would have guessed?

 

I did not read all the responses. You stated that you replaced the intake, but are u sure that u did not install the intake gaskets backwards and block off the front coolant passages.


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I did replace the intake. I was unaware that they had to go a certain way, so there's a possibility they are on backwards.


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I'm going to bet that you guys didn't see my thread from Saturday. I'm sure you'll enjoy it.

https://www.jalopyjournal.com/forum/threads/how-things-can-go-wrong.1060248/

 

You say the car is over heating is it boiling and over flowing or are you looking at the gauge ? Gauge could be bad if you don't see boiling ?

 

It's been pretty much solved that the fan blade is standard rotation mounted on a reverse rotation pump and belt system.

Here's the easy 1,2,3 15 min diagnosis of coolant flow restrictions in the block. If there's none (negative test) you're good. And there's no reason to go in or to keep looking at the block.

If it's a positive test showing restrictions you'll be going in to find them.

Drain the radiator via pet cock, Remove the t stat housing.
Attempting to Fill block thru intake manifold with 5 gallons of water .
The block should take that water as fast as you can possibly deliver it and drain out the pet cock without ever filling the intake.

 

So I remove the thermostat, reassemble and look for coolant flow through the radiator fill neck?


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Yes, there should be plenty of flow and movement Of water clearly visable when you start it.

If there's not, you need to figure out why. Pump impellers not pumping, pump inlet restrictions, this would be radiator and hose related. Or pump out put restrictions being in the block someplace

 

Yes

 

I did use the old style intake gaskets so I don't believe I have a restriction there. The old style are open on both ends.


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I may not be in no room to speak but no one has mentioned about the heater core. The reason I mention it is because you say on highway your fine in the beging of this thread The pressure of the rpms and wind keeping to force flow basically. But mayby heavy blockage at heater core? If that is even hooked up. If not you sure the fan(s) are installed on correctly and the pusher is not pulling and the puller is not pushing. Vise versa lol (that was confusing). You get what I'm saying. And that the flow of water pump is correct. Hek just buy a water pump. And put a tester radiator in it from the other truck and see. I mean man cooling issue foreal other than that timing plays a roll and fan does to and shroud and if the distance is close enough. On the mechanical fan. But you replaced that intake. I'm wondering if the ports are lining up or half way block off. Hard to say I'm thinking as I'm typing sheesh. But since you swaped your motor your radiator could have all the sediment all stuck in a line and all of a sudden blocked. If you have a laser temp tool. You can see if there are hot spots in your radiator. And you will know if it blocked and that making restriction flow

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You need to read the entire thread before you post! The OP has the wrong engine driver fan on, it is blowing towards the radiator, not sucking air through it. He is going to put the correct fan on it and test it. Read, read, read, before you post.

 

I had a 6-blade Chrysler fan with a shroud on my Ford and it would run 180 all the time (with a 180 stat) unless I got stuck in traffic and was at a crawl, then it got up to 210-220. I changed the fan to a flex fan I got at Summit, forget the brand but it was around $40. There have been a couple of hot-ish days in the last couple of weeks, got stuck in traffic on purpose and it runs a tad over 180. So the right fan makes a difference.

 

Lol, you're Kidding right??
Majority won't read past the 7th word and you really expect them to get thru 5 pages ?

 

IMO I would put the factory fan set up back on with the thermal clutch they use , it will freewheel at highway speeds when its temp is below the set point and will lock up when it gets to 210* and will suck lots of air ,
also when you replace the stat with the proper 190* one ( a 180 will do , use the AC delco #12TP1d as it a hi flow unit (or use the superstant thermostats ) , drill a small bleed hole in the tin so . air will be pushed out of the cooling system while idling and prevent a air lock by the themostat when refilling , which will keep it from opening as it doesn't see the water temp till it gets real hot ,
I wonder if the block bypass hole in behind the pump might be plugged and not circulating water while its warming up ( its the bottom hole on the passenger side of the pump when you pull the pump off they are sometimes plugged up when the system is negelected or in one case the guy went wacko with silicone and plugged it up . and it is needed to recirculate water so the thermostat will work properly and helps prevents pump cavitation )

 

Technically this is correct. But if the temp get's high enough, and builds enough pressure, even if the coolant is not boiling an old head gasket can fail, and that's worse than a boil over condition. So technically you are right. In practice, on an old engine this can be problematic.

How high of temp would you be comfortable with? Are you OK with 250* on a pre-65 vintage engine?

 

So I've gotten a general consensus that the 160* I put in should be changed back to a 195*?

Can someone elaborate on this please?


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I've also done some research on this fan and it's a 1730 CFM. Is this enough or should I get something with more CFM? Where should I be in terms of CFM?


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