Another Cooling Question...

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Joined
Aug 8, 2018
Messages
371
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191
Location
California
My Car
72 Fastback - 351C-4V, Fitech EFI, T56 Magnum 6 Speed
I'm finally starting to put some miles on my car and it just doesn't like traffic. When I'm going stoplight to stoplight on even moderately warm days the temp keeps climbing. I haven't had my EFI controller on when it's been at it's hottest so I don't know the exact temp but it start getting about 3/4 of the way up the analog gauge if I'm stuck at even a few lights. So far I haven't had a time when I was genuinely stuck in traffic for significant amounts of time but the entire time the temp gauge is climbing. It cools right down again once up to speed for any length of time. Once I shut off the engine it'll puke it's guts out into the overflow for a good 5 minutes and fills / empties the entire overflow. 

The whole cooling system is basically new. Water pump, Champion Radiator with dual fans, thermostat, hoses, etc. 

The engine is a 351C 4V with a mild to moderate cam (was in the car when I got it and no specs), headers, EFI, manual trans.

I want to be able to drive this thing without stressing about heat, let alone someday getting an AC in the car. Any advice on what could be going on or what I ought to do to cool it down more? Thanks

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It might not be your problem but the symptoms you have are the same as a backwards head gasket. Are you 100% sure you put the head gaskets on with the FRONT stamped on the gasket to the front? If you put the gaskets on with the mfg. logo up one is backwards. I got a great deal on my 73 because the guy never drove it for 25 years. He never had good reason why. When I got the car I did check to see that the baffle was in the block and that it had the correct 192 - 195 deg. thermostat and it did. But it got nearly to hot and when I turned off it blew the coolant out. That means there is a hot spot in a head that boils the water when no circulation at all. There are tiny holes in the head gasket that let some coolant into those areas.
On a Cleveland no core plugs in head to pop out to check but you can look with a mirror between head and block. The front bottom corner is nearly square and the rear corner has big radius and angle.. The previous owner of the car I got had put the R.H. gasket on backwards. New gaskets and no issue in 90+ heat and stop and go at huge car shows in Tenn. The picture is of how the gasket on the drivers side would look. You would flip the gasket over for L.H. side not rotate. The hole in the tab up top has to be to the front. Hope you took pics of your gaskets on the block. The previous owner of my car was a professional racer in California and his pit crew built the engine but still put one gasket on wrong. I have fixed several 289 and 302 that were backwards over the years.

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Dude,

what water pump pulley are you using ?

C90Z- 8509- B is listed @ 6-61/64'' and is generally used on non ac cars.

C90Z-8509- C is listed as 5-15/16'' and is used on ac cars, it will speed up your water pump.

I was having the same issue as you described and swapping pulleys worked for me, at least throw a tape across your pulley to determine which one you have, if you do a swap, don't forget you will need a shorter belt.

Boilermaster

 
Not sure if you read the thread about clutch fan versus flex fan? Your post says it has dual fans. I'm guessing that means their electric? 

Do you think they're pushing enough air through the radiator when you're at a standstill? It could just be a CFM issue?

Are they activated by a thermostat or by a switch? If it's just a thermostat you may be able to put an override switch in the blast air on to the radiator while you're sitting still.

 
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@Carolina_Mountain_Mustangs I've never had the heads off, so no idea on the gasket. Frankly hoping I don't have to take the heads off anytime soon.

@boilermaster This is the water pump I'm using https://www.summitracing.com/parts/mil-16235 with a 160F thermostat. 

 @ArtBBQ  The fans are controlled by temp and managed by the EFI. So I can have them come on whenever I want and stay on as long as needed. Right now I have them coming on at I think 170 as I'm trying to get ahead of the heat issue. Specs wise they pull plenty of air I think and under the hood it sure seems like they move way more air than the stock fan ever did. When they come on it's like a blast furnace under the hood. 

 
Just info on mine. I'm running EFI controlled. 2 12" spal that are about 3200 cfm total. I'm running a 185 stat with 1 fan turning on at 195 and the 2nd at 200. Car will hit 200 sitting at a light on 90+ day but will cool itself down. Never goes above 200 and mine is a mild built 408c.

Do you have the right type stat in? Bypass plate? 160 seems like a low stat. Clevelands like a lil heat.

 
Yeah I am thinking the thermostat is the place to start. I replaced all this stuff a couple of years ago when I first got the car and I don't recall much about the thermostat other than it was a 160. The car was running hot before that so a buddy told me to go lower on it and then I can just bring on the fans later if it's too cool. At the time I didn't know much about the Cleveland so I may well have just put in some over priced regular thermostat.  

If the restrictor plate is missing, does anyone sell just that?

 
Yeah I am thinking the thermostat is the place to start. I replaced all this stuff a couple of years ago when I first got the car and I don't recall much about the thermostat other than it was a 160. The car was running hot before that so a buddy told me to go lower on it and then I can just bring on the fans later if it's too cool. At the time I didn't know much about the Cleveland so I may well have just put in some over priced regular thermostat.  

If the restrictor plate is missing, does anyone sell just that?
https://www.tmeyerinc.com/

 
Dude,

I am using the same water pump as you are, however I am using a WCCC #53234 restrictor plate that allows me to use a WINDSOR type thermostat ( 195degree) the WCCC #53234 restrictor uses a (tiny bleed hole) that is recessed a little bit that allows the use of the windsor tstat.

I have never cared for the Cleveland style bypass and the crappy way it bypasses. (guess I pulled out too many fully opened cleveland thermostats that one could plainly see that the bypass cup would be off centered when fully opened.

Also have run into the 160 degree thermostat issues and EFI, they just plain DONT like a 160 degree thermostat and will not learn well

when they are constantly going back and forth between OPEN and CLOSED loop because the learn threshold is generally 165 degrees F.

your engine will also last a lot longer with a 190 or 195 degree stat.

I am using a 50 year old original 429 rad and shroud and a mechanical gauge and have ZERO cooling issues after using the smaller pulley and Windsor style restrictor and thermostat.

Boliermaster 

 
I went ahead and got one of the thermostats from TMeyer. Haven't fired up the car yet so no feedback on if that did the trick. 

But here's a nice thing :classic_sad: , I take out the thermostat and there's a chunk of metal wedged along it's edge. So I'm guessing a chunk of an old thermostat that rotted out or failed water pump, heater core or something like that. Of course now the is there any more of that crap in there waiting to clog up something important or trash the water pump? Now I think I need to start giving my car a daily baby aspirin to keep it from getting a blockage. 

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That is a strange chunk of gunk. Can you tell what kind of metal it is? It looks like it already came into contact with something, like the impeller on the water pump. 

 
It's steel, and yes looks like it's been chewed up pretty good. Looks a little like steel from a freeze plug. 

Also on the new thermostat, ran it for about 25 min in the driveway idling, fans coming on at 190. Eventually after closing the hood, temps started climbing and got to about 206 before I shut it off.

Certainly drivable but seems like it would eventually overheat if I left it running. Looking at adding an AC but need to get this sorted first. 

 
That certainly could be the case but it sure does seem to be moving a lot of water. Going to take it out for a drive in traffic and see how it does. It hasn't actually over heated yet, just the temp climbs and seems to keep climbing so doesn't seem like it would stop increasing. 

The way this thing heats up under the hood when not moving much makes me wish there was a way to reverse one one or both of the fans at slow speed. I know that won't work, but love the idea of getting some of that heat out from under there. 

 
If I had to guess that looks like the outlet or bypass connection nipple that sits in the block.

Someone maybe knocked it into the block by mistake when trying to change it.

Probably not hurting anything other than water flow.

If your cooling system is healthy (pump, pulley ratios, hoses, radiator not blocked etc.) then the low speed cooling issues are fan/ shroud related. If the temp drops when you are at speed, that indicates that the system can reject enough heat with more airflow across the rad.

Confirm that your thermostat matches the seat in the block.

Also, if you are using the factory gauge as your indicator I would get a second opinion- the OE gauge is a vague indicator of what's going on at best.

 
That makes sense actually.

On the surface everything looks good. Those dual electric fans move so much more air than the stock fan ever did. When they come on and the hood is open it's like a blast furnace all around there. Each fan is rated at 1328CFM. But I hear you, if everything seems to be working right then why is it hot?

I will triple check the thermostat. I have the factory gauge and a separate sensor and gauge in the EFI. And again It hasn't truly overheated yet, but just can't get it to hold temp at say 195-200F. It's start creeping up. I need to go get some miles on it and see how it does in traffic as so far that's been all in the driveway. But it seems to me that with all things being right, on a normal day in the low to mid 80s, it should be able to idle forever without overheating.  

 
So I ended up swapping one of my fans for a higher volume unit as a couple of you guys suggested and so far it's working great. I haven't had it out on a very hot day yet, but before even on a moderate day it wouldn't stay at a temp. Driving around in low 80's weather (the temp, not the decade) I set the fans to go on at 195 and off at 190 and it is great to see it actually going down in temp and the fans cycling on and off even just sitting at a light. 

This is the fan I ended up getting 

https://www.summitracing.com/parts/SPU-IX-30103202 

Thanks for the help on this!

 
It's steel, and yes looks like it's been chewed up pretty good. Looks a little like steel from a freeze plug. 

Also on the new thermostat, ran it for about 25 min in the driveway idling, fans coming on at 190. Eventually after closing the hood, temps started climbing and got to about 206 before I shut it off.

Certainly drivable but seems like it would eventually overheat if I left it running. Looking at adding an AC but need to get this sorted first. 
What bypass / restrictor plate do you have under the thermostat?

You may try digging out the old plate and putting in a new one from TMeyer.




 
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