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Discussion Starter · #1 ·
I have an 1987 5.0L I bought used. I converted it from EFI to carb.
Is it ok to block the heater core port at the water pump and at the intake manifold? I'm running this motor on a stand and the water temp keeps rising. The radiator is from a 5.0L mustang and I have a pretty strong fan blowing through it. The water pump is new. I changed the thermostat tonight and it still gets hot. Now I'm wondering if it is a problem to have the heater code ports blocked? Any comments are appreciated.
-Jeff
 

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The manifold to heater core hoses can't be blocked off and still get good cooling results, but you CAN run the manifold port to the water pump port with one hose.
No blocking of the heater hose's ! I'm going to tell all the 5.0 guy's without a heater , they have a over heating problem

engine is running to lean or that fan is'nt doing the job / both
 

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I have an 1987 5.0L I bought used. I converted it from EFI to carb.
Is it ok to block the heater core port at the water pump and at the intake manifold? I'm running this motor on a stand and the water temp keeps rising. The radiator is from a 5.0L mustang and I have a pretty strong fan blowing through it. The water pump is new. I changed the thermostat tonight and it still gets hot. Now I'm wondering if it is a problem to have the heater code ports blocked? Any comments are appreciated.
-Jeff
Put a fan on the ENGINE... You wont push enough air with an electric fan as you stated. UNLESS it IS a pusher fan from a vehicle. I have seen them blocked with no problems but I always do a loop myself, its possible you have an airpocket and cant get the system 'burped' But not knowing HOW hot you are talking so I wont suggest a lean condition, Nor will I suggest that, you are certain the gauge is correct....
 

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Older cars and trucks used to have shutoffs on the heater hose when you wanted the heater off for Max AC or the ones with comfort stream ventilation. I do remember seeing a new Ford truck with heater delete in the early 70's, came with rubber cap and hose clamps on the ports. You do have to have the thermostat bypass hose hooked up though. Wonder if the engine stand has the engine to level and should be tilted more?
 

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Discussion Starter · #7 ·
thanks for the feedback. I'll try a hose to jump the heater core ports together. Or, I might just remove the thermostat completely. Then I can start looking at some of the other suggestions like Lean condition and fan.
I tried to make sure all the air was out of the system by disconnecting the upper radiator hose at the T-stat housing and filling the radiator as much as I could before coolant filled the T-stat housing. I also made sure the radiator cap was the highest point of the system.
 

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thanks for the feedback. I'll try a hose to jump the heater core ports together. Or, I might just remove the thermostat completely. Then I can start looking at some of the other suggestions like Lean condition and fan.
I tried to make sure all the air was out of the system by disconnecting the upper radiator hose at the T-stat housing and filling the radiator as much as I could before coolant filled the T-stat housing. I also made sure the radiator cap was the highest point of the system.
taking the hose off the T/S did nothing , removing the t/s and housing would have . Or leaving the intake heater hose off while filling coolant system . do the later , very easy for a complete fill that way

thats just to make sure of C/system .
also your got the ing. timing correct ?
 

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Discussion Starter · #11 ·
tried no t-stat and 20 inch box fan, still have run-away water temp. Can try unblocking my heater core ports but seems like something is seriously wrong. Maybe the water pump I bought is bad. I can't imagine what could be wrong with the pump. I have a serpentine set up and the pump is rotating in the opposite direction of the crankshaft. During one of my start-ups I left the radiator cap off and watched for flow. I had the t-stat in at this time and once it warmed up enough, the flow increased significantly. I think I'm ok there but don't know now
 

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:confused:

This is a used engine you purchased correct? Did you listen to the engine run in a chassis before buying or was it already out? How long running before it overheats? It has the WP bypass hose, correct? Are you sure the system is completely filled? Loop the heater hose inlet/outlet.

Do you see any bubbles in the fill tank when running? Any indication of coolant in the engine oil?

I converted it from EFI to carb.
...hmm...

What intake gasket kit did you use?
 

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taking the hose off the T/S did nothing , removing the t/s and housing would have . Or leaving the intake heater hose off while filling coolant system . do the later , very easy for a complete fill that way

thats just to make sure of C/system .
also your got the ing. timing correct ?
Do this if you haven't already.
 

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tried no t-stat and 20 inch box fan, still have run-away water temp. Can try unblocking my heater core ports but seems like something is seriously wrong. Maybe the water pump I bought is bad. I can't imagine what could be wrong with the pump. I have a serpentine set up and the pump is rotating in the opposite direction of the crankshaft. During one of my start-ups I left the radiator cap off and watched for flow. I had the t-stat in at this time and once it warmed up enough, the flow increased significantly. I think I'm ok there but don't know now

Are you SURE the pump IS turning the correct way? Had that happen once on a motor swap, and the kid swapped to v-belt with a serpentine style pump...
 

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my first thought was the wrong pump . OP said just efi to intake/carb

op , doesnt know how to fill a coolant system . would also have problem over heating with efi

OP , hook up a vacuum gage , see if there is a low reading
 

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Put a fan on the ENGINE... You wont push enough air with an electric fan as you stated. UNLESS it IS a pusher fan from a vehicle. I have seen them blocked with no problems
THIS. You do NOT need to loop the heater core. It's fine. Just be sure to keep the little hose that goes between the water pump to the thermostat housing.

Engines get notoriously hot when they are revved at 2500+ rpm just sitting still for longer periods of time on an engine stand, or even in the car. You need PLENTY of air flow. A single 'pusher' fan isn't going to cut it.

Removing the thermostat will only delay the inevitable. That move will NOT cure a cooling problem. It will just make it take longer to warm up.

That being said, some of those 5.0's with the serpentine belts had REVERSE rotation water pumps. Make SURE you're not spinning the water pump in the opposite direction it was designed for, or it will never stay cool.

BTW, I like your engine run-in stand!

Good Luck!
 

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I have an 1987 5.0L I bought used. I converted it from EFI to carb.
KULTULZ Then Asked- said:
...hmm...

What intake gasket kit did you use?
The reason I ask is that the coolant ports are unique on the later 5.0L HO engines and an earlier style intake manifold may have trouble sealing to a later style head-
 

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He would have to modify heavily the stand he has fabricated to use a driven fan. It would also have to have a shroud for extended runs. The overheating seems to take place quickly and the air flow is not the problem (IMO) (as long as he has a strong electric fan mounted @ the front center of the radiator). There is a flow restriction somewhere as evidenced by the timing of the thermostat opening.

I would like to see him loop the heater hose connections just to see what will happen.

I would also like to see him modify the run-in stand with a MARK VII cooling module.
 

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Discussion Starter · #20 ·
Thanks for all the good feedback. I did not get a chance to hear this engine run before I bought it. That's why I made the stand. I did not want to take a running 6 cyl out of my '62 Falcon and replace it with this motor (plus a T5) without being sure it was going to run. I want to hear it run, do a compression test and leak down test.
Today, when cold, I checked for coolant in the oil there was none. I tried to unblock the heater core ports and crate a loop of heater hose. The temp still got hot. Then I checked the ignition timing and it was retarded. I advanced it and now the temp regulates at about 210 degrees. Still hot but now it regulates. Maybe the air flow through the radiator is not enough in comparison to at stock fan. The cooling system pressure did not become grater than the radiator cap rating (14lbs) as it did in the previous tests.
I started shopping for an electric fan which I could use on the stand and eventually in the Falcon. I attached a few photos of the Falcon and my other toys. Ford, Pontiac, Chevy, I don't discriminate as long as it throws you back in the seat and has a clutch pedal.:D
Thanks again for the help.
 

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