63 Dart overheating issue

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Dicer said:
Yes, I have read that later in the tread, I guess I spoke too soon. Reading about the freeze plugs being "MIA" gets me to thinking. Crack block, cracked head, bad head gasket can all cause overheating problems. I wish you the best, you really did a nice job on this auto sir......
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I had been concerned about that as well at first but I found the originals in a box in the trunk and they were corroded out. That was why they were removed. I have replaced the head gasket and have had no signs of a cracked head or block. Have monitored for leaks and coolant in oil or exhaust. None in either.
 
With the temps you say and have some cool spots on radiator I think you're on the right track to pull radiator. possible major restriction or combustion gasses getting into cooling system. If you have an air compressor, I would disconnect the heater core and flush block and heater core separate with water and air to blast it out several times. let us know after you get the radiator back.
 
moparlvr166 said:
With the temps you say and have some cool spots on radiator I think you're on the right track to pull radiator. possible major restriction or combustion gasses getting into cooling system. If you have an air compressor, I would disconnect the heater core and flush block and heater core separate with water and air to blast it out several times. let us know after you get the radiator back.
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I agree. I think he stumbled upon the real issue. Only one way to know for sure now.
 
Heater core is brand new. Installed after full flush was done. Timing mark on balancer was confirmed.

Plan to pull the rad tomorrow if weather holds out and time allows
 
Mineallmine said:
I have a new rad cap for the car as well, but not installed yet. I doubt that will change anything as the temperature goes up to almost hot before the pressure pushes past the cap.
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Lets start with this. The inability to hold pressure anywhere in the system will allow the temperature to rise once vapor begins to form in the system.
See if you can get your hands on a tester. They usually have adapters to check caps as well as the system.
Looks like this
1689169063504.png

Side note: A radiator without a recovery tank will be full cold about an inch below the cap.


Mineallmine said:
Let me correct that. I am actually at 7.5 btdc. I forgot I adjusted it. I tried 2.5 and 5 but it didn't like it. Starts and runs much better at 7.5. maybe I'll back it off again to see if it changes anything
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Mineallmine said:
I think my mechanical is fine. I know when I rev it when I was setting it with vacuum disconnected it changed with rpms. I'll check the vacuum. The hose is connected to the correct port on the side of the carb.
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Mineallmine said:
Stock pulleys.
Adjusted timing to 2.5 BTDC and adjusted carb to run well with timing setting - no change.
Temp hits about 250-260 and is boiling over.
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With Regards to timing:
A. Its seems close enough that should not be the cause of overheating.
B. RPM RPM RPM
The RPM of the measurement is important. Centrifical advance adds to the intial above 600 or 650 rpm.
So 2.5* BTDC at fast idle is retarded.
2.5*BTDC should be at slow idle specification. I'll guess around 600 rpm is the spec. Could even be 550 rpm "with lights on" (so the alternator is adding load).


Mineallmine said:
Oh, and one thing I forgot to mention. I checked the vacuum at the carb. Basically none at idle but gets stronger as rpms increase. Don't have a vacuum guage so i can't tell you exact measurements. Also again I checked mechanical advance with the vacuum disconnected and as you increase the RPMs the timing changes as well so I'm confident that is all correct as well.
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No vacuum advance at idle is correct.
 
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Mattax said:
Lets start with this. The inability to hold pressure anywhere in the system will allow the temperature to rise once vapor begins to form in the system.
See if you can get your hands on a tester. They usually have adapters to check caps as well as the system.
Looks like this
View attachment 1716113661
Side note: A radiator without a recovery tank will be full cold about an inch below the cap.








With Regards to timing:
A. Its seems close enough that should not be the cause of overheating.
B. RPM RPM RPM
The RPM of the measurement is important. Centrifical advance adds to the intial above 600 or 650 rpm.
So 2.5* BTDC at fast idle is retarded.
2.5*BTDC should be at slow idle specification. I'll guess around 600 rpm is the spec. Could even be 550 rpm "with lights on" (so the alternator is adding load).




No vacuum advance at idle is correct.
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I think you misunderstood what I was saying, or I miswrote. Either way. It is holding good pressure. It only pukes out past the cap once it almost reaches hot on the gauge inside the car.

RPM was set close to 600RPM (nice slow idle). That is how the timing was set, with vacuum disconnected and plugged.

Fluid level was set to about 1 inch below cap as well (no overflow bottle...yet).

All great information. Most of this I am familiar with, some not as much.

I am pretty confident I have found the issue to be a plugged radiator. Reason I didn't go there immediately was the fact that it was redone by a reputable shop. Once I got it out and drained and got the scope inside it is clear there are a bunch of clogged tubes. Must have had a pocket of crap that didn't loosen up with the original air blow out or original flush. Thinking it had to come loose the first time the car got driving and heated up and bouncing around. I was just remembering that I am pretty sure the first few runs it only ever got up to the low end of the operating range, where I figured it should be. Either way, it is dropped off at the shop to be hot tanked and flushed and flow checked to be sure it's good to go.

I also forward and backward flushed the engine after the rad was pulled to try to get any residual dirt out. Hopefully I'll be good to go for some time to come.
 
Update:

Picked up the radiator from the shop today. Couldn't believe it was actually CHEAPER than the quote...by almost half. Gotta love when that happens. Anyway, put it back in with new cap and thermostat and fresh coolant and took it out for a drive.

HUGE difference. Had it out for 40 minutes and it never even got to the lower line of the operating range. Even the hot start has improved (not gone but much better. makes sense that the engine is cooler, so is the fuel).

Think I'm going to bump the timing back up a little to 5 BTDC as it doesn't seem to like the 2.5 BTDC. I doesn't start as nice and it's boggy, along with not as good of an idle, even after adjusting the carb. Ran great at 7.5 BTDC so I will try 5 and see how it goes, now that I know the root cause of my issues.
 
When filling wait for the gauge to tick upwards to show the thermostat came open, and not installed backwards. Then top off. Your system wasn't originally designed for a overflow reservoir. You may need to go to a different pressure rated cap.

I am sure you have E10 in Canada. Ethanol will yellow and crack that filter. Go to a metal filter. Don't use one of those turd glass filters either.

I swapped an F body radiator into my Duster. It kept puking coolant. It was designed to have an overflow bottle with that radiator cap. I added one before going to the track.
 
I had the same problem with my 63 dart . I tried everything. As a last resort, I pull the water pump and compared it to the one I took off motor during rebuild.
The impeller on the new water pump was smaller than the old water pump. I reinstalled old water pump and problem solved
 
Mattax said:
Lets start with this. The inability to hold pressure anywhere in the system will allow the temperature to rise once vapor begins to form in the system.
See if you can get your hands on a tester. They usually have adapters to check caps as well as the system.
Looks like this
View attachment 1716113661
Side note: A radiator without a recovery tank will be full cold about an inch below the cap.








With Regards to timing:
A. Its seems close enough that should not be the cause of overheating.
B. RPM RPM RPM
The RPM of the measurement is important. Centrifical advance adds to the intial above 600 or 650 rpm.
So 2.5* BTDC at fast idle is retarded.
2.5*BTDC should be at slow idle specification. I'll guess around 600 rpm is the spec. Could even be 550 rpm "with lights on" (so the alternator is adding load).




No vacuum advance at idle is correct.
Click to expand...
GREAT starting point! Also another EASY thing to do.......remove the radiator cap and start the engine. Let it warm all the way up with thermostat OPEN. Now with the cap off, and YOU OUT OF THE WAY of the radiator fill neck, rev the engine and see what the coolant in the top tank does. If it comes OUT of the fill neck, the radiator is stopped up, because the coolant is being pumped into the top tank and has nowhere to go.
 
my63Dart said:
I had the same problem with my 63 dart . I tried everything. As a last resort, I pull the water pump and compared it to the one I took off motor during rebuild.
The impeller on the new water pump was smaller than the old water pump. I reinstalled old water pump and problem solved
Click to expand...
You didn't happen to snap pics of them did You?? Where did the pump come from, & what branding did it have?
 
Rug_Trucker said:
When filling wait for the gauge to tick upwards to show the thermostat came open, and not installed backwards. Then top off. Your system wasn't originally designed for a overflow reservoir. You may need to go to a different pressure rated cap.

I am sure you have E10 in Canada. Ethanol will yellow and crack that filter. Go to a metal filter. Don't use one of those turd glass filters either.

I swapped an F body radiator into my Duster. It kept puking coolant. It was designed to have an overflow bottle with that radiator cap. I added one before going to the track.
Click to expand...
None of these radiators are "designed" to be "With or W/O" overflow reservoirs. No reservoir= fill & leave an air gap in top of rad tank for expansion, reservoir= fill it to the tippy-top. A number of old-school rads had a strip of brass soldered in the tank that indicated where You should stop filling them.
I added a reservoir to My '72 Swinger A/C car, doing nothing else but filling it to the top. You should always run a higher pressure cap, regardless of the use of a recovery tank/reservoir.

You're 100% right on the fuel filters, those are great if you're dealing with an issue to monitor for excessive dirt & debris, and to check for adequate fuel flow. Once things are OK tho', pitch 'em & put a proper metal filter on!!!
 
Draining the radiator of the coolant mix, removing the lower hose, covering the outlet of the rad, refilling with water to the top, and quickly uncovering the outlet one can see how quickly or slowly all the water comes out. Backyard style diagnosis but you can get a good indication of whether it’s obstructed or not if you’ve done it enough times with new or unobstructed radiators and ones that are plugged up for whatever reason. Works on heater cores as well using a garden hose gauging by how much water comes out the other port as well as how much backs up and try’s to push the spray nozzle away from the hose end your shooting water in.
 
So, final update.

It appears the overheating problem is solved. It was definitely the rad. Once it was flushed it ran extremely cool. Now it doesn't really get to operating range without the thermostat. I am still getting some debris coming through so I have flushed it out a few more times. Water is finally almost clear after a run or two. One or two more times and I can pull the rad one final time for a good cleanout and reinstall with thermostat and fresh clean coolant and I'll be good to go.

Will be doing it soon as in a few more weeks temps will start to get closer to freezing than I would like running pure water. Only takes one cold snap to mess things up. Don't want to go there.

Super glad it was an easy resolution. Too bad my heat soak issue is still there. Not as bad but not gone.
 
Don’t know what to say. Ours is a slightly hot rodded 225 with a radiator from Bob at GlenRay. It run cool as a cucumber in Arizona heat.

F2776D64-3791-4177-A1B2-031F23ECAE69.jpeg
 
Mine runs really cool now that I got all the crap out of the engine. I am pretty confident the root cause was the radiator got plugged up after a deposit in the engine let go and went through the system. Now it doesn't even get up to the lower operating range line even on our hotter summer days.
 
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